Harvey’s Mammoth Deluge Potential: Some Models Are Showing Storm Could Produce Five Feet of Rain

Media, Texas, and Gulf Coast residents take note: the thing to be most concerned about with regards to Harvey is not its admittedly life-threatening storm surge and strong winds, but what is shaping up to be a potentially historic rainfall event.

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The latest update from the National Hurricane Center shows that Harvey continues to strengthen and is now a category 4 storm. Packing 130 mph winds and a 941 mb minimum central pressure, the storm is certainly now very powerful. This new intensity is above the NHC’s previously expected peak strength for the storm just prior to landfall late tonight. The situation is thus becoming ever more dangerous.

But with Harvey, the serious concern we are facing is not just the usual and notably very dangerous high winds and storm surge flooding that go along with a category 4 storm. We are also looking at very severe and long lasting flooding rains that will have the potential to cause damage and disruption for not just months but for years to come.

A Devastating Rainfall Potential

(Southeast Texas has never seen 60 inches of rainfall from a tropical system. But that potential exists with Harvey.)

Consensus models now predict that peak rainfall totals will be around 35 inches in association with Harvey. This is due to the dual facts that Harvey is currently a very moisture-rich storm and that the storm is expected to stall for between 5 and 10 days following landfall. The storm is predicted to hover along the coastline, drawing in an unusually intense flow of moisture from a much warmer than normal Gulf, and to generate severe thunderstorms hour after hour, day after day. And this kind of rain event, if it emerges, could produce a disaster of historic proportions for Texas.

It’s worth noting that rainfall totals could also exceed the consensus forecast. Some models are now predicting upwards of 50 or 60 inches of rainfall by the time Harvey leaves the Texas area later next week (see top image above). The highest rainfall amounts ever produced by a tropical cyclone, in our records, for Texas is 48 inches. But there’s at least some possibility, with the perfect rainstorm that appears to be shaping up in Harvey, that these ultimate rainfall totals will be exceeded and a disaster of unprecedented proportions could emerge. But even if this worst-case doesn’t emerge, a 35 inch rainfall event would wreck untold destruction upon Texas’s southeastern cities.

Harvey strengthening as it moves toward shore

( Harvey rapidly strengthening to CAT 4 as it nears landfall. Image source: National Hurricane Center.)

Normally soft-spoken forecasters like Bob Henson and Eric Holthaus are not mincing words over the potential severity of the present situation. Last night, Bob Henson on twitter asked people: “Please don’t fixate on whether Harvey arrives as a Cat 2, 3, or 4. It’s the mammoth rainfall amounts (up to 35″) that will affect millions.” Meanwhile, Eric Holthaus warned: “This is scary. I have never seen a rainfall forecast like this in my entire career. Texas will be recovering from for years.”

Of course, we could dodge a bullet and rainfall totals could be lower for Harvey. It’s just that this event is currently trending toward a near worst case or worst case deluge-type storm that produces very heavy rains over the same region over nearly a week-long period.

Conditions in Context — This is Not Your Father’s Atmosphere

(The number of record rainfall events has increased dramatically during recent years. An observation attributed to human-forced climate change. Image source: Increased Record-Breaking Precipitation Events Under Global Warming.)

During recent years, a warmer than normal atmosphere has been producing more and more intense rain storms. The number of record daily rainfall instances around the world has been rising precipitously (see image above). This increasing severity is, in large part, due to the fact that human-forced warming amps up the hydrological cycle — producing more intense rain storms and more intense droughts. In other words, the climate dice are loaded for extreme rainfall and droughts in the present atmosphere. And it is in this atmosphere that Harvey has emerged. So we shouldn’t at all discount the fact that Harvey’s potential worst impacts from rainfall are now higher than they would have been even just a few decades ago. And this is one of the major reasons why we are seeing such a historic potential out of Harvey.

UPDATED (4)

UPDATE (5): As of 800 PM CDT the eye of Harvey crossed the coastline somewhere between Corpus Christi and Port O’Connor. Unfortunately, this storm is just getting started as a very severe one week long rain event is about to follow.

UPDATE (6): As of 1000 PM CDT and just following landfall, Harvey’s minimum central pressure had fallen to 938 mb. An indication that the storm was still strengthening as it began to cross the coastline. According to these reports (here and here), this is the 4th lowest barometric pressure recorded for a hurricane at landfall on the Texas coast since 1900. Maximum sustained winds remained at 130 mph with gusts to 160 mph.

Links:

National Hurricane Center

National Weather Service

Increased Record-Breaking Precipitation Events Under Global Warming

Greg Carbin

Eric Holthaus

Bob Henson

Hat tip to Greg

Hat tip to Titania

Hat tip to Wili

Hat tip to Andy in San Diego

Hat tip to Wharf Rat

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Climate Change May be Readying to Split the Heavens over the U.S. Southeast — So What Can We Do?

None of us are bystanders when it comes to climate change. Whether we’re aware of it or not, we’re all caught up in the most pressing trouble of our age. Our great burning of fossil fuels is steadily turning the Earth’s climate into something terrible. Once we realize this, the imperative for action becomes as clear and keen as a razor’s edge.

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Only a few weeks after severe rains inundated Louisiana, another powerful atmospheric bomb may be leveling its sights toward a broad region of Florida and the US Southeast. Rainfall amounts in excess of one foot are expected over portions of Florida as a tropical depression is expected to strengthen into a tropical storm as it churns in from a record-hot Gulf of Mexico. Coastal portions of Georgia, South Carolina and North Carolina may see 5-10 inches of rain over the coming few days. And long range forecasts indicate a possible tropical storm or weak hurricane threat to interests from the Outer Banks through New England by late this week.

The storm, fueled by unprecedented levels of ocean and atmospheric heat and moisture, has the potential to dump rains at rates capable of overwhelming local infrastructure. If this happens, vehicles and homes will once more be under the gun for severe and damaging flooding in a summer that has seen a seemingly endless litany of such events across the U.S. and around the world.

Florida Floods Inbound

(NOAA QPC forecast shows that parts of coastal Florida near Tampa could experience more than a foot of rainfall this week as a tropical depression moves in from the Gulf. Heavy rains are predicted to hammer most of Florida and the U.S. southeastern coastline. Such rainfall events are fueled by global warming which generates a heavier load of moisture held aloft in the Earth’s atmosphere, producing more extreme rainfall events.  Image source: NOAA.)

Behind the 8-Ball on Climate Change

Events like these increasingly drive home the point — whether we like it or not, we are now entering a new climate era. How dangerous and destructive that era will be still depends on our actions as individuals, communities, and nations.

Earlier this month, the IPCC issued two stark announcements. Though probably not a surprise to readers and researchers here, these statements will likely come as a shock to most of the climate-concerned world. The first statement indicated that the Paris 2 degrees Celsius target could not now be achieved without a rapid reduction of fossil-fuel burning to about zero combined with the application of a number of yet-to-be-developed negative carbon emissions technologies that would draw some of that massive, heat-trapping CO2 overburden out of the air. The second statement declared that given the likely difficulty of hitting the 2 C target, and considering the fact that 2016 will probably have already hit near 1.2 C above 1880s temperatures, the feasibility of keeping warming below Paris’ provisional 1.5 C target is now highly questionable.

In other words, even the fast-feedback biased Equilibrium Climate Sensitivity models show that the window for 1.5 C is probably closed and the 2 C window is slamming shut pretty fast. To this point, we should give a concerned nod to Hansen et al.’s shot-across-the-bow assessment of paleoclimate, where the 405 parts per million CO2 and 490 ppm CO2e currently in the Earth’s atmosphere hints that long-term warming from simply a maintained level of these greenhouse gasses is about 3-4 C (see How Sensitive is our Climate?).

Regardless of how climate sensitivity ultimately pans out, the world is in kind of a rough spot with some bad climate outcomes likely already locked in. Sadly, we are experiencing the first forays of these now, as the past week brings news of a freak lightning strike killing hundreds of Arctic-native reindeer in Norway, while three tropical cyclones formed simultaneously in the record-hot Atlantic. Tropical Depression 9 is expected to dump a foot or more of rainfall over parts of Florida just a couple of weeks after Louisiana experienced a flood disaster whose damages now rival that of Hurricane Andrew — resulting in a massive housing crisis with 86,000 people seeking federal aid.

Lake Mead New Record Lows

(Warming the Earth’s atmosphere increases both evaporation and precipitation intensity, resulting in more extreme floods and droughts. We see this in various record rain and drought events now ranging the world. At Lake Mead, Nevada — a key U.S. reservoir — water levels again hit new record lows this year, nearing the mandatory end-year rationing level of 1,075 feet. Image source: U.S. Lakes Online.)

At the same time, and on the other end of the hydrological scale from Louisiana (and possibly Florida), Lake Mead, Nevada, after suffering from a decades-long Colorado River drought, is edging closer to the mandatory rationing line where multiple states will see water supplies cut. Practically everywhere we look, from species migrating toward the poles, to ever-more-extreme weather, to the worst global coral-bleaching event on record, to the burning Amazon rainforest, to the thawing tundra, to diseases like Zika leaping out of the tropics, to algae blooms spreading dead zones into rivers, lakes, and oceans, we can see these climate impacts growing stronger and starker.

Meanwhile, near-future vulnerabilities are becoming clearer. In one example, the Department of Energy just issued a new report showing, as has been stated here on this blog many times, that our current centralized power infrastructure is very vulnerable to even relatively moderate levels of warming, related extreme weather, and sea level rise.

The trouble is getting locked in, but it becomes even worse if we continue to emit carbon, to burn fossil fuels. So given this harsh context — a context that should be a call to action for everyone living upon the warming Earth — there is now clear and present cause to both ask and answer the question, What can we do? How can we respond before climate chaos sets in and it becomes difficult or even impossible to act effectively?

Mobilization for Climate Action

Many years ago, I asked the same question of myself — what could I do?

Back in 2011, after having kept a close watch on the emerging threat that was climate change and after having read James Hansen’s seminal book, Storms of My Grandchildren, I decided that something had to be done. 350.org was holding a ‘stop the pipeline’ rally that November and I signed up to participate. I wanted to get arrested along with climate leader Bill McKibben, but I let myself be swayed by family concerns. So braver and more noble souls than I stood on that thin line. Nonetheless, I did my own small part. More importantly, I returned from the rally even more resolved and, in a few short months, I started this blog. My climate activism has continued ever since.

Stop the Pipeline

(350.org and NRDC’s spearhead effort to stop the Keystone XL Pipeline was ultimately successful due to broad and ardent climate activism. However, in order to prevent the worst effects of climate change, a great number of other pipelines, wells, and coal mines will have to be blocked or halted. It’s a simple fact, really, that we need to choose between a livable future and continuing to burn dangerous fuels. And that’s the reason why political participation and activism is so very important at this time. Image source: On Earth.)

Another person I respect, my father-in-law, is a long-standing member of the Sierra Club. If you’re not familiar, the Sierra Club is a 126-year-old environmental organization that supports an active transition away from fossil fuels and is currently involved in various anti-fracking and coal plant shutdown actions. This summer, my father-in-law participated in county meetings in King George, Virginia in an effort to get fracking banned in that region. For some reason, fossil-fuel interests are keen to frack King George. Apparently, there’s a decent amount of tight oil in this part of Virginia. In any case, my father-in-law helped to get strong anti-fracking regulations put in place for the county — so strong that the fracking interests are now, like TransCanada, threatening to sue.

We Can Do This Together

My good friend Colorado Bob used to be an oil worker. He, like so many of us, was part of a system that generated the harms that are now coming. Bob is now one of the most outspoken advocates for climate awareness and action that I know. For years, he’s written and linked to internet articles on the subject of climate change. He’s an active voice on some of the most prominent climate forums, like Weather Underground and ClimateProgress to name just a couple. Bob’s out there every day doing something to raise awareness, to educate people, to get us all moving in the right direction. Many of the concerned people who frequent this blog like Greg, Wili, Cate, DT Lange, ThereAreSoManyThings, TheSecularJurist, Kevin, June, Mulga, Redsky, Leland Palmer, Spike, Bill h, mlparrish and so many more have done something similar.

NASA Modified poster

(Houston, we have a problem… NASA recently modified this World War II-era poster to illustrate the need for a global mobilization to prevent harm due to human-caused climate change. Join NASA and become a part of that necessary action today. Image source: NASA.)

There’s an active debate ongoing as to whether or not climate scientists should become political advocates for climate action. Underlying this debate is a notion that climate change is somehow an issue with sides — that there’s some kind of legit, moral, non-biased middle ground a scientifically informed person can take. The truth is that climate change simply will continue to happen and worsen if we keep burning fossil fuels, and that non-bias in this case can swiftly tip into immorality. Once it is realized that climate change will result in mass migration, mass destruction of wealth and property, and a high risk of mass loss of human and animal life, it becomes abundantly clear that something must be done. These facts render the issue of climate neutrality in the sciences a moot point. Even those intending to remain non-biased will inevitably draw fire, as simply reporting facts on the issue, as Michael Mann found during the 2000s, has made scientists a target of fossil-fuel monetary and political interests seeking to obscure these facts from the public eye — a simple truth that scientists like James Hansen realized long ago. In his case, activism was not just morally courageous, it was practical and scientific. Something terrible was happening, would continue to happen if we didn’t do something about it. Hansen’s point on this was amazingly clear:

Only in the last few years did the science crystallize, revealing the urgency – our planet really is in peril. If we do not change course soon, we will hand our children a situation that is out of their control… [emphasis added]

As out-of-control as that future threatens to become, the bravery and resolve of some of this nation’s children in the face of that threat is, quite frankly, astonishing. If you think you’re too young to act, just take a look at Our Children’s Trust. In this case, a group of preteens and teenagers are taking on the federal government over climate change. They’re claiming that the government isn’t living up to its sacred pledge to protect their health and welfare. If these kids have the intestinal fortitude to go at the Feds with all legal guns blazing, to set aside huge chunks of their lives to take on an issue that is so important to everyone, then there’s no excuse for us adults.

Every Life Matters

Back when I was writing about Hurricane Sandy slamming into the U.S. northeast, my wife was involved in the sheltering of animals displaced by the disaster, as part of the response effort in the region. She and many others spent days housed in the gymnasium at a local community college, taking cold showers and eating rations provided by local disaster agencies, putting themselves at risk walking dogs as a powerful ice storm followed the devastating coastal low. Their compassion for the voiceless, the innocent and the helpless are a part of what we will need to effectively deal with climate change. Part of our challenge will be to help the living creatures and forests of our world survive the rapid warming and the climate disruptions that result. We must open our hearts to the plight of the innocent, the poor, and the voiceless, and not turn our eyes away in callous denial of harm done.

Fish Lizard Island

(When it comes to facing climate change, every life matters. From fish, to coral reefs, to forests, to polar bears, to companion animals, to human beings, confronting climate change is ultimately an effort to save lives. Great Barrier Reef image source: The Guardian.)

Have my father-in-law, Colorado Bob, McKibben, Hansen, Mann, Our Children’s Trust, my wife and tens of thousands of other advocates, scientists, and everyday people won the war on climate change? Heck no. We see the results of our present failings with increasing extremity each and every day. But the point is that our actions have mattered and, more importantly, have become a part of a potential for heroism on a mass scale, a global effort to shift energy and climate policy and to help those that suffer due to the changes. All of us have the opportunity now to become a part of what will probably be the biggest life-saving effort ever undertaken by our race.

A Call to Act

Big or small, all our actions have an impact and we can all do something through the simple impetus of deciding to do the right thing. We can join 350.org and the Sierra Club, we can vote for candidates who promise strong action on climate change, we can speak out in support of the science, we can cut the lion’s share of meat out of our diets, we can install solar panels on homes and businesses, we can ride bikes, and support electric vehicles. We can raise awareness among our families, friends and neighbors. We can plant gardens and help to rejuvenate the carbon-capturing soil. We can join community, state, national and international aid and response networks to help people and animals harmed or displaced by climate change. We can defend the IPCC and other scientific agencies from politically-motivated attacks by fossil-fuel special interests. We can all become part of the action supporting positive responses and blocking the use of destructive fuels like oil, gas and coal.

What we ultimately choose to do first is not as important as the simple decision to begin to do something. The important thing is to act, to act now, and to resolve to do more each day. To become a part of a necessary growing effort. To stand up and make the moral decision to become a soldier in a global mobilization, not only to fight for the lives of our children and grandchildren, but for all the poor and innocent creatures of this Earth — human or otherwise — who are now so vulnerable to a rising disaster of fossil-fuel burning’s making.

So please join with me in lifting our voices in this call to act, swiftly, with purpose, and now.

Links:

IPCC — Two degree climate target not possible without ‘negative emissions’

IPCC Special Report to Scruitinize Feasibility of 1.5 C Climate Goal

How Sensitive is Our Climate?

Climate Sensitivity, Sea Level Rise, and Atmospheric CO2

Lightning Kills 323 Reindeer in Norway

NOAA

350.org

Sierra Club

The Guardian

Our Children’s Trust

The Hockey Stick and the Climate Wars

NASA

Weather Underground

ClimateProgress

King George Moves to Protect Water Supply From Fracking

On Earth

Storms of My Grandchildren

Our Grid is Incredibly Vulnerable to Climate Change

Bill McKibben

NRDC

Hat tip to Greg

Hat tip to DT Lange

Hat tip to Colorado Bob

Ellicott City Flood — 1,000 Year Event Looks a Lot Like One of the Rain Bombs of Climate Change

We live in a strange new world, one in which the familiar is all mixed up with the radically altered. Such was the case this weekend when a weather pattern that was pretty normal for summer spawned a single thunderstorm that produced a once-in-a-thousand-years flood event in Ellicott City.

Normal Weekend, Typical Weather Pattern, Abnormal Conditions

On Saturday, my wife and I readied to trek out to Shenandoah National Park for a happily-anticipated summer camping trip. As we headed out the door, the weather pattern looked mostly normal for summer, if a little stormy. A high-pressure system out over the ocean was pulling in moisture off its waters and drawing warm air up from the south. A low over western Pennsylvania and a warm frontal boundary over Maryland created instability in a big zone of convection from Northern Virginia on through to Connecticut. Overall, it was a pretty typical pattern that would probably have produced some moderate-to-strong late-afternoon thunderstorms back in the 20th century. Back then, it was far less likely that a similar pattern would have produced a 1,000 year flood event.

Extreme Ocean Heat 2

(Extremely warm sea surface temperatures on the weekend of July 30-31 helped to fuel the record rainfall event over Elicott City, Maryland. Sea surface temperature anomaly map provided by: Earth Nullschool.)

However, conditions were not normal, not the same as they were back during a time when human fossil-fuel emissions hadn’t forced the world to warm by 1.2 degrees Celsius above 1880s levels. In the new world in 2016, the ocean high-pressure system was circulating over record warm sea surfaces that were 3-5 C hotter than late 20th-century averages. And because of this, the ocean was bleeding off a whole hell of a lot more moisture than it typically would. Any storms that fired in that very wet air mass would, as a result, tend to pump out a lot more rain than is typical.

A Wet Atmosphere Crackling with Unusual Energy

As my wife and I made our way toward the Blue Ridge Mountains and down Interstate 66 and Route 211, large, energetic cumulus clouds sprouted all around us. Wafted in the hot, unstable air, many tops punched up through the troposphere, spreading out into the characteristic anvil shapes of thunderstorms.

Light streamed down between these big, wet beasts. For a while, as we made our way up to the campground, set up our gear, and took a hike along a local rock scramble, we were fortunate — able to enjoy our day despite the loud rumbles and roars of thunder echoing up from the valleys or off the nearby mountainsides in the steamy, moisture-choked air.

Available Rainfall Saturday

(A massive amount of atmospheric moisture fueled powerful thunderstorms on Saturday, July 30 from the Appalachians of northwestern Virginia to the Baltimore City region. One of these storms dumped more than 4.5 inches of rain on Ellicott City, Maryland Saturday in just one hour. Image source: Terp Weather.)

At about 3,000 feet in elevation, these conditions were a bit odd for Shenandoah National Park which typically experiences milder weather. Temperatures were around 80 degrees Fahrenheit (about 5-6 F hotter than average), and the level of atmospheric moisture was amazing. Great, steamy clouds kept rolling up the mountainsides. They made the air heavy and full of shapes dancing with light and shadow, seeming to give it the character of some alive thing sprouting a thousand wet heads and arms.

The big thermals and thunderstorms were supported by hotter temperatures into the 90s (F) down in the valleys. And the storms were taller, bearing more moisture, engorged by a hot atmosphere whose temperatures and water vapor levels are now probably unlike anything seen in at least the past 115,000 years — conditions that would have devastating effect just a couple of hours later and about 100 miles to the east in Ellicott City.

Returning to camp, as we prepared for a hearty dinner of tempeh and veggie pasta, thunder from the southwest grew ever closer and a rolling wave of cloud seemed to spill in through the trees, spreading mist and heavy rain over everything nearby. In just a few minutes, we were scrambling into our vehicle and watching as torrents of rain streamed down, transforming the mountaintop campground into a world of rushing water.

Thunderstorm Dumps More Rain on Ellicott City than Any of the Past Deluges or Hurricanes in its History

At about the same time that my wife and I were scrambling for cover, another massive thunderstorm was bearing down on Ellicott City, Maryland. The storm hit one of the densest pockets of atmospheric moisture in that big bleed off the record-hot Atlantic Ocean and just exploded. Packed with all that unusual and heat-fueled moisture, the storm then began to dump its amazing and unprecedented torrents on this historic town of 65,000 just 20 miles to the west of Baltimore. In only 60 minutes this massive thunderstorm managed to unload 4.5 inches of rainfall. Two-hour rainfall totals approached six inches.

(Restaurant-goers in Ellicott City watch in shock as the street below floods and sends vehicles hurtling past. Video source: Ellicott City Flash Flood.)

Streets were rapidly flooded as the Patapsco River rose to a record 14 feet and leaped over its banks. The main road running through the center of town became a four-to-six-foot-deep torrent that hurtled vehicles along its path or into buildings. First responders scrambled to rescue more than a hundred motorists who were suddenly stranded in the flash flood. Tragically, two people lost their lives.

The force of the flood was so energetic that not only were many of the historic buildings in town damaged, but some had their very foundations torqued off-center, twisted by the great energy of the sudden flood waters churning through town. The Maryland government has declared a state of emergency, but it is uncertain how long it will take to make repairs or how much that is irreplaceable has been lost in the flood.

Two 100+ Year Flood Events For Ellicott City in the Past Five Years

The Washington Post’s Capital Weather Gang appropriately notes that Ellicott City is a pretty vulnerable place for floods:

It’s a highly vulnerable spot, an urbanized strip along the bottom of a deep valley through which the Patapsco River flows. This place, historic Ellicott City, Md., has seen plenty of serious floods: 1868, 1923, 1952. More recently, the remnants of Hurricane Agnes (1972) left an extreme high-water mark, measured in many feet. The Great Mid-Atlantic Flood of June 2006, once again drowned parts of the town.

And another big flood back in 2011 pushed the Patapsco River to 11 feet, prompting a local art gallery to build a 20-inch-high flood barrier. But the unforeseen flood that roared into Ellicott this past Saturday was the worst among all of these. As a result, most protections and flood barriers previously erected were quickly overwhelmed.

Phoenix Macroburst 2

(Dramatic microburst over Phoenix, Arizona on July 21, 2016. Each degree Celsius of warming increases the atmosphere’s water vapor content by about seven percent. This increase, along with other factors such as intensified convection and rising cloud tops, escalates the frequency of extreme rainfall events like the July 30, 2016 Ellicott City flood. Image source: GGferg.)

Two-inch-per-hour rainfall amounts are usually enough to completely overwhelm most drainage infrastructure, overtop banks, and turn streets into rivers. Ellicott City saw nearly six inches of rainfall in two hours and 4.56 inches of rainfall in just one. Such events are typically seen as quite rare (100-year events or more) and building codes do not often account for them. Managing so much water is a major engineering challenge and requires a great deal of investment. Spending so much money on flood defense systems for a storm that might happen in 100 years or 1,000 years can sometimes seem like a waste at the time.

However, in a world warmed by climate change, such floods are happening with greater frequency. A 100 to 1,000 year flood may happen every five years or so in some locations (as has been the case with Ellicott for 2011 and 2016). The atmosphere is loaded more and more with both heat and moisture. The troposphere is taller due to the heat. The oceans are warmer and bleed more moisture. All these factors combine to make even pop-up storms more intense and to generate the 100 and 1,000 year events with a higher frequency in the present day. And as the world continues to warm, such severe storms will become ever more common.

Links:

Ellicott City Gets Rainfall Expected Only Once in a Millenium

Two Dead, 100 Rescued as Ellicott City Flood Causes Tremendous Devastation

Ellicott City Flash Flood

Earth Nullschool

How an Off-the-Charts Flood Ravaged Ellicott City

NASA GISS

Terp Weather

Hat tip to Colorado Bob

Hat tip to DT Lange

Hat tip to Greg

Hat tip to Griffin

Climate Change and a Mangled Jet Stream: Historic May Deluge for Bosnia and Serbia

Over the past week, a powerful heat dome high pressure system grew ever-more-entrenched over a region just north of the Caspian Sea. This sprawling high pushed an extreme amplitude ridge pattern north toward Arctic Russia, Scandinavia, and the Kara and Barents Seas. Behind this ridge, toward Central and Eastern Europe, a deep trough dipole pattern developed. A cold and unstable pit in the atmosphere hungry for storms and drawing in energy from the far-north Arctic near Svalbard.

By late Tuesday, the deep pit had fallen down into a cut-off and powerful low pressure system, wringing out the moisture spilling off the heat dome high. By today, that system had turned into a kind of inland hurricane as it dumped as much as four months worth of rainfall in less than 40 hours over broad sections of Bosnia and Serbia.

Serbia Floods May 15

(The very vision of a hydrological cycle amped-up by human-caused climate change — deluge over Bosnia and Serbia. Image source: LANCE-MODIS.)

The result was a staggering inundation of water that cut off entire towns, knocked out bridges, left thousands of people stranded and resulted in the loss of at least 5 souls. Flood waters surged through towns and villages, carrying away cars, capsizing homes, and turning streets into torrents. Hillsides collapsed into slurries of muck and the two main north-south rail lines through Serbia and Bosnia were cut off.

By today, officials were declaring the event the worst water disaster ever to occur in the region. Prime Minister Aleksandar Vucic made an embattled appeal for aid from neighboring countries saying:

“What we are facing is the biggest water catastrophe in Serbia’s history.”

According to reports from Serbia Independent News, rainfall rates were the highest ever measured in all of the 120 year record. Records in Bosnia also hit their highest levels since measurements began in 1894.

In Bosnia, Maglaj, a town some 60 miles north of Sarajevo was inundated by a massive water surge, forcing 6,000 to evacuate as others climbed onto rooftops to avoid the rushing water. Harried Maglai Mayor Mehmed Mustabasic noted:

“The situation is alarming. We have no electricity, the phones are not working. We are cut off from the rest of the world.”

(Euro-News assessment of the still-ongoing disaster)

Bosnian and Serbian military helicopters scoured the countryside for stranded persons, ultimately evacuating hundreds more. EU troops stationed in the Balkans joined in with trucks and more helicopters, but many roads remained impassable either due to flooding or to heavy snowfall blanketing higher elevations. Almost all schools across the widely impacted region were closed.

“We have engaged all our manpower,” said Predrag Maric, a Serbian emergency official, as strong winds and rain cut off a key road to Croatia. “Water is rising everywhere.”

Unfortunately, the cut-off low pressure system setting off this historic storm is now entrenched and will likely continue to bring severe weather to the region into early Saturday. So relief is not likely to come until the weekend.

UPDATE: As of late Sunday, the upper level low remained in place dumping heavy rainfall over the Balkans. The area of major impact expanded into Croatia as nearly fifty souls have now been taken by this extraordinarily extreme event. New update article to follow later today or tomorrow.

Links:

LANCE-MODIS

Daily Rainfall in Belgrade Hits Record

Five Dead in Worst Floods to Hit Bosnia in 120 Years

Record Rain Causes Flooding Across the Balkans, Hundreds Evacuated

Hat-tip to Colorado Bob

 

107.9 litres per square metre in Belgrade, 110 litres per square metre in Loznica and 108.2 litres per square metre in ValjevoRead More at inserbia.info/today/2014/05/daily-rainfall-in-belgrade-valjevo-and-loznica-hits-record/ © InSerbia News
107.9 litres per square metre in Belgrade, 110 litres per square metre in Loznica and 108.2 litres per square metre in Valjevo,Read More at inserbia.info/today/2014/05/daily-rainfall-in-belgrade-valjevo-and-loznica-hits-record/ © InSerbia News
107.9 litres per square metre in Belgrade, 110 litres per square metre in Loznica and 108.2 litres per square metre in Valjevo,Read More at inserbia.info/today/2014/05/daily-rainfall-in-belgrade-valjevo-and-loznica-hits-record/ © InSerbia News

 

The Neverending Deluge: Pacific Heat + Fixed Jet Stream Parks Anomalous January Cyclone Lingling Over Philippines For Two Weeks

The vulnerable island chain that is the Philippines already sits on the firing line of tropical storm devastation. During a typical year, about 20 tropical cyclones roar ashore, wrecking all sorts of havoc. In a typical year, this amazing parade of such cyclones begins in June.

But now it appears that weather in the Philippines, which was already rather extreme, has gotten much worse. For so far, this island nation has been treated to a tropical storm season that hasn’t ended for at least 20 months. The storm season didn’t end in 2013, when January 1rst saw the formation of that year’s first tropical cyclone. And the season didn’t end with the winter of 2014 when the devastating rainmaker that was Tropical Storm Lingling formed on January 10th.

Lingling_2014_track

(Lingling Track. Image source: Commons)

Lingling developed to the east of the Philippines over a pool of abnormally hot and deep warm water. Temperature anomalies for this region ranged up to 2.5 C above average. Perhaps more importantly and more ominously, the depth of this abnormally warm water extended far below the surface.

In a Deepening Pool of Hot Water

Such strange and anomalous conditions are expected under a regime of intensifying human-caused warming. In the hottest regions of the ocean, evaporation is expected to intensify as warmth increases. Eventually, the surface water becomes saltier as it becomes hotter, causing it to sink. This mechanism transfers heat deeper and deeper into the world’s tropical oceans. This process is the start of a dangerous ocean turnover. One related to hypoxia, ocean current changes, and stratification. And it appears that just such a perilous heat transfer is beginning in a region of the Pacific east of the Philippines.

We won’t go too far into detail about the initial signs of tropical ocean warming and turnover or its other hazards and implications here. However, suffice it to say that a deepening hot water pool in this region of the world appears to, at this time, be having a profound impact on storm formation and strength. Namely, it has spawned the almost constant progression of storms mentioned above. A hurricane season without end for two years. It is also the mechanism that, according to NOAA fueled the extraordinarily powerful Typhoon Haiyan, one of the strongest storms on record, which devastated the Philippines in November of 2013.

Now the same zone has spawned the epic rainmaker that is Lingling to again harry the Philippines just two months later.

The Storm that Wouldn’t End Forces More Than a Million to Flee

Lingling formed over this anomalously deep, hot water then marched in through the southern reaches of the Philippines where it has been dumping copious amounts of rain over the islands ever since. You can note the almost zero movement of the cyclone from January 11 to January 23 in the MODIS image sequence below:

Lingling January 11

Lingling Janary 16

Lingling January 23

(Lingling January 11, 16 and 23. Image source: Lance-Modis)

By January 22nd, over the course of 11 days of near-biblical flooding, the storm had inundated some parts of the Philippines with an astonishing 52 inches of rainfall, more than the amount New York receives in an entire year. By today, the never-ending deluge had resulted in 1.14 million evacuated, 63 missing, and over 54 lost lives. Numerous bridges and dams were also destroyed by the flooding, along with hundreds of homes. This, just two months after the strongest tropical cyclone ever to make landfall struck the northern part of this vulnerable island chain.

And with the anomalous January formation of a devastatingly persistent Lingling, there is simply no respite.

Jet Stream Lag, Stalled Fronts, and Hot, Deep Water

Lingling’s persistence over the Philippines for so long can be attributed to numerous factors. First, the storm was caught up in a stalled frontal boundary whose tail end had snagged over the Philippines for about 15 days running. The front itself was caught up in a Jet Stream trough shoved south by a disrupted and collapsing polar vortex (one that currently appears to be in the process of getting ripped in half). So Lingling became indirectly linked with polar amplification related events further north.

The stalled frontal boundary and related Jet Stream lag also resulted in Lingling remaining parked over hot Pacific waters of great depth. Normally, the cyclonic action of the storm would pump cooler, deeper waters to the surface and result in the storm’s weakening. Unfortunately, the deeper waters were also quite warm, so Lingling maintained enough strength to continue dumping epic amounts of rain over the Philippines for two weeks straight.

Lingling front entagled 20 Jan

(Lingling, lower left, entangled in frontal system stretching all the way across the western Pacific on January 20, 2014. Front entanglement in a fixed Jet Stream pattern and related stalled frontal boundary helped result in Lingling’s 2 week persistence. Image source: Lance-Modis.)

This combination of conditions: hot, deep water, exceedingly early tropical storm formation (such that there is essentially no end to the Pacific cyclone season) and a lagging, persistent Jet Stream pattern resulting in an entirely abnormal storm event are unlikely to have occurred without the added weather forcing of human caused warming.

Unfortunately, the Philippines, at least for this year as in 2013, are likely to expect storm formation and impact to continue on throughout the year. Water conditions are certainly warm enough. So we will likely see the current 20 month storm season continue for another 11. A shift in winds, blowing the warmer waters east with an El Nino might bring some brief respite. But with human caused climate change pushing temperatures ever higher, we are likely to see the waters continue to warm, eventually over-riding such variability. In the end, the Philippines is indeed likely to see a never ending storm season.

Links:

Four Feet of Rain Floods the Philippines

More than a Million Forced From Their Homes by Lingling

NASA Lance-Modis

Commons

NOAA: Deep, Warm Water Fuels Haiyan Intensification

Through the Looking Glass of the Great Dying

190 mph Monster Cyclone Now the Strongest Hurricane Since 1980

Arctic ‘Heat Wave’ to Rip Polar Vortex in Half

Hat Tip to Colorado Bob

Mangled Jet Stream Brings Worst Storms in Five Decades to Sichuan China; Approach of Super Typhoon Soulik to Result in Hybrid Rain Superstorm?

A persistent south-north flow of the Jet Stream has dredged moisture up from the Indian Ocean, India and Bangladesh and deposited it in a deluge that has persisted over Sichuan, China for at least the past five days. Rainfall in many areas were the worst seen since weather records began in 1954. In one example, the city of Dujiangyan experienced 37 inches of rainfall over the course of 40 hours.

The floods forced nearly 100,000 people to evacuate and have impacted at least 2 million people across the region. Over 200 people are feared dead or missing. With some towns buried under as much as 20 feet of water, thousands of homes and buildings have been destroyed or damaged with transportation brought to a stand-still in many of the effected regions. In hard-hit Dujiangyan, a local resort was buried when a hillside collapsed, burying the area to tree-top level in mud and debris and spurring the evacuation of 352 tourists. Raging floodwaters also caused a nearby bridge collapse that sent at least six vehicles into raging flood waters.

In the video below, provided by KIDgrownup, we can see the raging floodwaters washing away buildings and heavy equipment as people flee the disaster site:

Changed Jet Stream Causes Dangerous, Persistent Weather Pattern as Super Typhoon Approaches

A dwindling, but still significant, number of media sources continue to claim that we cannot attribute single events such as the most recent Sichuan Floods to climate change. Unfortunately, this claim is simply untrue. Climate is a measure of weather over a given area during a long period of time. As climate changes so does the weather. In Europe, for example, major flood events are now twice as likely as they were forty years ago. This 100% increase in floods can be directly attributed to changes in Europe’s climate and, as such, fully 50% of each new major flood is, therefore attributable to climate change. And the fact that the most extreme floods are getting more extreme can also be attributed to climate change. In this case, saying a single record flood event, like the current Sichuan flood, cannot be attributed to climate change is at least 50% untrue. Would a flood like this have occurred, eventually, if climate hadn’t changed? Probably. But it likely would have happened 50, 100, 200 years or more later. Would it have happened this year, the way it did, without climate change? Absolutely not.

At the micro level, we can also look at weather patterns and clearly point out how they are not normal and how they’ve changed as a result of human-caused climate impacts. In the example of this week’s Sichuan Floods, the Jet Stream created conditions where heavy rains, so far, have stalled over Sichuan to inundate the region.

Sichuan Floods July 8

(Sichuan Floods, July 8. Image source: Lance-Modis)

In the above image we can see a thick blot of clouds hovering over Sichuan in Central China. This dense band of clouds is the result of a cut off upper air flow of the Jet Stream forming a strong, persistent upper level disturbance. To the south, we can see a broad band of clouds and moisture being drawn into the system from the Indian ocean and over India, Bangladesh, Thailand and Vietnam. To the east, a tropical system in the Korean Sea also contributes moisture to feed this large storm.

What is most unusual about this particular weather pattern is that it doesn’t move. And we can see this when we switch to today’s Lance-Modis shot. The below image is 4 days later than the July 8 shot. But the storm over Central China has hardly budged.

Sichuan Floods July 11

(Sichuan Floods July 11. Image source: Lance-Modis)

In this shot, the cut off upper level flow in the Jet Stream remains, the dense cloud pack over Central China remains, the strong upper level low remains, and the moisture flow from the Indian Ocean and related regions remain. Ominously, the only marked difference in this shot is the looming approach of super typhoon Soulik from the China Sea. This major typhoon packs winds in excess of 140 miles per hour and could cause severe damage to Taiwan. However, it’s the ability of this system to deliver moisture into an already moisture rich upper level air flow that may result in even worse conditions for Eastern and Central China over the next few days as the storm is projected to make landfall in Eastern China, then track as far as 200 miles west of Shanghai. At this point, some weather models, including the ECMWF ensemble, show Soulik getting absorbed by the cut-off upper level low now parked over China. Were this to happen, the resulting rain event could be far more substantial than even the record floods seen over the past few days.

The Climate Change Link To Extreme Weather

So how did climate change create the conditions in which this dangerous situation emerged?

  1. The upper level Jet Stream was caused to meander due to a climate change induced loss of sea ice and summer snow cover.
  2. These changes resulted in a slower progression of weather patterns and more cut-off upper level disturbances.
  3. The added atmospheric heat content added both moisture and instability, adding fuel for storms like this one.
  4. Increased ocean temperatures made moisture and heat delivery from ocean systems and tropical cyclones more likely.

Without these conditions, the Sichuan floods were unlikely to have happened with such force, violence and to have been so persistent and long-lasting. And now, a bad situation is made worse via the ocean delivery of a super typhoon, just one of many more frequent storms to plague this region over the last 40 years. An increased frequency a recent scientific study also attributes to climate change.

Hybrid rain superstorm to form over China? Hopefully, not. But, at this point, things aren’t looking too good.

Links:

Lance-Modis

Rainstorms Flood Sichuan China

China Floods Death Toll Rises

Taiwan Evacuates 2,000 Tourists as Super Typhoon Soulik Looms

ECMWF

 

 

 

 

 

 

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