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U.S. Northeast Battered by Second ‘Once in a Generation’ Storm This Year

A major nor’easter is lashing the Eastern U.S. today. Reports of moderate to severe tidal flooding are racking up as hurricane force gusts are pushing mounds of water inland and raking the coastline with tremendously powerful waves.

This storm blew up to extreme intensity over the night-time and early morning hours on Friday as two low pressure cells converged off the U.S. coast. By afternoon, the storm had bombed out to 970 mb and was still intensifying.

A broad region across the northeast from D.C. to Maine are now experiencing wind gusts of 50 to 80 mph or more with local power outages and downed lines reported over a broad region. The gusts are so strong and widespread that diverse locations all throughout the Northeast are seeing instances of toppled trees, damage to structures and falling limbs. In Chambersburg, PA, the raging gusts tipped over a school bus.

On the coast, extremely strong winds for a nor’easter and conditions more akin to a hurricane are driving directly in to shore from Chatham and Nantucket northward. As a result, weather authorities are predicting a historic coastal flood event for metropolitan areas like Boston. There, record high tides may be exceeded as winds there are now blowing at a vicious 80 mph.

(A broadening storm is lashing most of the Northeastern U.S. with gale and hurricane force winds even as a places like Boston face massive waves and record storm surge flooding. Image source: Earth Nullschool.)

But what is, perhaps, more concerning is the fact that this storm is still gathering strength. And due to a blocking high over Greenland, the storm — dubbed Riley — is likely to only slowly move off-shore. So its impacts will tend to persist for multiple high tide cycles even as its circulation broadens and it generates an east-to-west fetch of gale to hurricane force winds stretching over a 400 to 600 mile region of ocean and driving directly toward the Northeast and East Coasts.

This will enable a long-lasting storm surge that will generate serious flooding for hundreds of miles of coastline. And on top of that surge, towering waves will relentlessly batter the coast throughout Friday and Saturday. Already the flooding has become quite severe for a number of locations. But the situation is likely to get worse before it gets better. With the worst impacts expected at high tide late tonight.

Scenes like these bring back recollections of Sandy. And like Sandy, the present cyclone has been influenced in a number of ways by human-caused climate change.

The storm’s historic intensity was first fed by a large plume of moisture issuing off a much warmer than normal Gulf of Mexico. Instability, driven by a deep diving trough, formed a low sweeping over the north-central U.S. that then tapped this high volume of moisture. The latent heat in the moisture enabled stronger than normal convection which helped to spike the storm’s early intensity.

(Extremely warm sea surface temperatures both in the Gulf of Mexico and off the U.S. East Coast are helping to fuel the present storm’s record intensity. This is just one of the climate change associated factors contributing to the present storm. Image source: Earth Nullschool.)

Off shore, the Gulf Stream waters are also far warmer than normal. Ranging as high as 9 degrees Celsius above average, this abnormal heat helped to fuel a second plume of moisture and instability. And as these two areas of storminess merged, they rapidly bombed out to high intensity even as their area of storm wind circulation broadened.

To the north, a recent (climate change driven) polar warming event has generated a kind of train wreck in the upper level winds that typically hurry storm systems along. As a result of this train wreck, a blocking high over Greenland is preventing this heat-amplified storm from tracking eastward. Over the next 48 hours, this block will allow a massive pile of water and towering waves to relentlessly hammer the Northeastern and Eastern Coasts of the U.S.

(Large waves and long fetch which is predicted to be generated by this storm on Saturday could produce serious and wide-ranging impacts all up and down the Eastern Seaboard from Hatteras to Portland and points northward. Image source: Earth Nullschool.)

Presently, this storm is expected to produce the second 1 in 100 year flood event that the Boston area has seen in the past year. Under typical climate variability, the likelihood of seeing back-to-back events of this kind would be 1 in 10,000. However, due to the influences of human-caused climate change, the potential for extreme weather events like the one we are presently enduring are greatly enhanced.

(UPDATES TO FOLLOW)

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Climate Change — Seas Are Now So High it Only Takes a King Tide to Flood the US East Coast

“It gets higher every year. I imagine it will be worse next year.” Guido Pena, Miami marina employee commenting on water levels during king tides.

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King tide. It’s a new term for an old phenomena. One that few people noticed before human-forced climate change began to push the world’s oceans higher and higher.

During spring and fall, the sun lines up with the moon and other astronomical bodies to produce a stronger gravitational pull on the Earth. This pull, in its turn, affects the tides — generating higher and lower tides over certain regions of the world.

(Rising ocean levels due to human-forced climate change is resulting in worsening instances of tidal flooding at times of high tide. In this video, a simple seasonal high tide is enough to flood major roads in Fort Lauderdale on October 17.)

King Tides — Turned into Flooding Events by Climate Change

During past years, these events were called astronomical high and low tides. They weren’t typically a news item because such tides often did not produce flooding. Past construction had placed buildings and key infrastructure above the typical annual range of even the astronomical high tides.

However, during the past century and, ever more-so during recent years, seas have been rising more and more rapidly due to human-caused climate change. A warming of the Earth due to fossil fuel burning that has melted glacial ice — flooding the oceans and causing its waters to thermally expand. As a result, parts of the U.S. East Coast now see ocean levels that are 1.5 feet or more higher than they were at the start of the 20th Century.

This rise, though modest compared to what will happen if global temperatures and greenhouse gas levels remain at currently elevated levels or continue to ramp higher, is now enough to turn astronomical high tides into a notable flooding event. An event that we have begun to call a king tide.

miami-sea-level-trend

(In places like Miami along the US East Coast, sea levels are rising at a swifter and swifter rate due to human-caused climate change. Note the acceleration in the rate of water rise since 2008 indicated in the above graph. Image source: FSU.)

A Climate Change Enabled Tidal Flooding Event Impacting Most of the U.S. East Coast

And over the past few days, from Florida to Boston, the US East Coast has been feeling the effects of just such a climate change caused sea level rise. In Florida, a debate between climate change denier republican Marco Rubio and his democratic opponent Patrick Murphy was held at a site where the local street was flooding due to salt water incursion. Murphy, responding to his opponent’s doubts that seas were actually rising stated:

“Look out your window, right? There’s two or three inches of saltwater on the roads right now. They were not built underwater. Go down to the Florida Keys. The reefs are dying from acidification and bleaching.”

All across Florida, residents were posting pictures on twitter of the rising ocean waters and commenting on the intensification of coastal flooding due to sea level rise during recent years. “It gets higher every year,” said Guido Peña, a Miami Marina employee where the water was shin deep Monday morning, in a statement to the Miami Herald. “I imagine it will be worse next year.”

All up and down the coastline, communities reeling after a raking blow from Hurricane Matthew were again seeing waters rushing up and past the dune line or invading low-lying streets and neighborhoods. But this flooding was due to no hurricane, just the added rise of waters caused by a fossil-fueled warming of the Earth, a melting of her glaciers, and the thermal expansion of her seas.

(King tide flooding enhanced by climate change is now able to completely submerge Long Wharf in Boston.)

In Boston, residents took pictures of a completely submerged Long Wharf yesterday. Mentions of climate change came along with the observations of flooding waters. These included some ominous notes for a future in which scientists are projecting at least another 2 feet of sea level rise for the US East Coast by mid-century (and possibly quite a bit more).

High Vulnerability for U.S. East Coast

Overall, the US East Coast is particularly vulnerable to climate change induced sea level rise. Much of the southeast is subsiding due to crustal rebound following the last ice age which compounds any overall ocean rise. In addition, changes in North Atlantic Ocean currents and wind patterns due to climate change will tend to cause water previously pulled north by the Gulf Stream to rebound against the coastline. An effect that could also add another 1-3 feet of water rise to any baseline total provided by glacial melt and thermal expansion.

Larger news sources like The Weather Channel have provided little context with regards to the impact of climate change on current king tides — simply stating that climate change may affect king tides in the future. However, we should be very clear that without climate change we would not see the flooding from these tides that is now apparent today.

Links:

When the Ocean Rolls onto the Roads, King Tide Sends a Message

What’s a King Tide and Why is it Flooding Boston’s Waterfront?

Marco Rubio Denies Climate Change as King Tides Flood Miami Streets

FSU

Hat tip to Jack Ridley

Hat tip to Greg

Hat tip to DT Lange

Hat tip to Jean Nagy

Hat tip to Ben Kennedy

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