“I can hear your whisper and distant mutter. I can smell your damp on the breeze and in the sky I see the halo of your violence. Storm I know you are coming.”
The atmospheric ingredients right now are ripe for some serious trouble. Globally, the world is just starting to back away from the hottest temperatures ever recorded. This never-before-seen heat plume, driven on by a fossil-fuel abetted warming not seen in at least 115,000 years and an extreme El Nino combined, has loaded an unprecedented amount of moisture into the Earth’s atmosphere. As El Nino shifts toward La Nina and the Earth marginally cools, a portion of this massive excess of water vapor is bound to fall out as rain — manifesting as terrible extreme precipitation episodes that can result in serious trouble. A seemingly endless procession of freak events that challenge the record books time and time again.
Across the world, we’re starting to see such episodes now. Over the past week, Iran, Yemen, Qatar Saudi Arabia and Afghanistan have experienced flash floods resulting in loss of life. Severe floods spurred a major emergency response effort in Central and Northern Russia this weekend. And in Santiago Chile, streets turned into rivers as a sudden and extraordinary deluge both polluted the water supplies of 1 million people and transformed the world’s largest copper mine into a lake.
(Severe flooding around the world this week includes the Houston area — sections of which have essentially been crippled by 12-18 inches of rainfall over the past 24 hours. In total, more than 1,200 water rescues have been reported throughout the region. Many residents, like the gentleman above, appear to have been shocked and surprised by the flooding’s severity. Video source: Houston ABC News.)
Sudden, Extreme Flooding in Houston Area
In the US, the City of Houston and the region of southeastern Texas experienced its own extreme deluge. There, a stubborn and unyielding high pressure system over the US East Coast, an omega block in the Jet Stream, a cut off upper level low, and a nearly unprecedented amount of moisture streaming in from the Gulf of Mexico and regions to the Equatorial South all conspired to aim a train of powerful storms in the form of an eye-popping mesoscale convective system (MCS) at the Houston region. Since early this morning, between 12-18 inches of rainfall fell over the city’s western suburbs with 6-8 inches inundating the city center. In some places, rates of rainfall accumulation hit a crippling rate of nearly 4 inches per hour.
According to Bob Henson at Weather Underground:
… the Houston area was socked on Monday morning by a huge mesoscale convective system (MCS) that drifted southeast across the area, dumping eye-popping amounts of rain: 6” – 8” over central Houston, with 12” – 18” common over the far western suburbs… While individual thunderstorms often weaken after dark, the large mass of thunderstorms that makes up an MCS will often persist overnight and into the next morning, as the MCS cloud tops radiate heat to space and instability is enhanced.
The record single day rainfall total for Houston before today was 11.25 inches. It appears likely that 11.75 inches recorded at Houston International Airport today will mark a new daily high mark for a city that grew up out of fossil fuel burning but now appears to be drowning in the heat-intensified effluent. More to the point, most of Houston’s western suburbs experienced what amounts to an entire typical season’s worth of rainfall in just one 24 hour period.
Drainage systems, not designed to handle anywhere near so much water over so short a period, were rapidly overwhelmed. By midday, more than 70 subdivisions in the Houston region were reported flooded, more than 1,200 vehicle water rescue operations had been conducted along the inundated region’s streets and highways, and more than 1,000 homes were inundated. Seven hospitals were shut down, airport operations were crippled, and more than 100,000 people were reported to be without power. The Weather Channel’s Jim Cantore, not known for understatement, may have hit a bit below the mark when he noted that “this is a mind boggling situation” earlier this afternoon. CNN, in its summation report of this, most recent, disaster declared that the entire city had been basically shut down.
(River of moisture flows up from the Equator and Gulf of Mexico and into the Houston region on Monday — spurring extreme rains that cripple the city. A pair of doggedly persistent weather systems — a blocking high to the east and an upper level low to the north contributed to the extreme weather over Houston. Climate change related features like record atmospheric moisture loading, and persistent ridge and trough generation due to Jet Stream changes likely linked to record low Arctic sea ice levels also likely influenced today’s severe storms. Image source: LANCE MODIS.)
As of early this evening, a series of somewhat less intense storms still trailed through the Houston region as heavier rains marched off toward the east over Louisiana and Arkansas. A strong moisture flow is expected to persist over Eastern Texas and the southern Mississippi River Valley region through to at least Thursday as both the upper level low and blocking high complicit in Monday’s extreme flooding in Houston appear reluctant to budge from their current positions. As a result, NOAA is predicting another 4-5 inches of rainfall for areas near and just to the North and East of Houston over the next seven days. To this point, it’s worth noting that NOAA’s precipitation models had ‘only’ predicted about 4 inches of rainfall for the past 24 hour period in the near Houston area — a period that produced about five times that total for some locations. So it appears that weather models may be having a little bit of trouble managing the new and extremely dynamic atmospheric conditions now coming into play.
But One Extreme Event of Many in the Past Five Months
Houston’s likely record rainfall for this time of year comes on the back of hailstorms generating up to a billion dollars worth of damage over Northeastern Texas last week and follows a record March inundation of the Mississippi River region just to the North and East. An event that also followed a freak December flooding of Missouri and Illinois which likewise re-organized the record books. Overall, this represents an extreme spate of severe weather for one localized region.
Consistent trough generation in the Jet Stream over the area (likely influenced by record low Arctic sea ice coverage), consistent above average sea surface temperatures in the Gulf of Mexico, a strong moisture flow from a record El Nino, and record global temperatures contributing to high atmospheric moisture loadings all influenced severe storm formation over this area during recent months. Sadly, it’s a spate of severe weather that is likely to continue at least until the end of Spring.
Hat Tip to Colorado Bob
Hat Tip to Greg
Hat Tip to DT Lange
Hat Tip to Daniel Hatem