Saturday, October 31, 2015

Extreme Texas Flood, Storms Signs Of Things To Come?

Part of a trailer on the roof of a three-story
Holiday Inn Express in Texas after
an early morning tornado Friday.  
Friday was as horrible a day as you can imagine in much of Texas, especially in and near Austin, as tremendous amounts of rain caused immense flooding, and early morning tornadoes trashed parts of several communities.

Austin received nearly six inches of rain in just an hour, which is almost unheard of. A trailer, probably used to tow cars or ATVs or something, ended up on the roof of a three-story Holiday Inn Express, tossed there by a violent pre-dawn tornado.

At least two people are dead in the storms.

The worst of the flooding hit in some of the same areas slammed by deadly flooding in May. The Blanco River near San Marcos, Texas crested above 40 feet for only the second time since 1920. The other time it was above 40 feet was in May.

Flooding continued overnight and into Saturday as heavy rounds of thunderstorms continued across much of Texas. The threat spread east from central Texas.

Before dawn Saturday, the action shifted to the Houston metro area. Just like central Texas was being slammed by tornadoes and flash flood early Friday, there are reports of tornado damage and widespread flash flooding, evacuations and water rescues this morning in a broad area in and around Houston. 

Flash flood watches for the possibility of heavy rain have also spread east into Louisiana and Mississipi. Already this morning there has been at least one tornado warning in Louisiana this morning, and flash flood warnings are popping up there, too.

This storm in Texas was epic, in a year in which many parts of the nation and the world have been hit by some of the most extreme rainfall in modern times.

It's hard to pin one or two storms on any particular global phenomenon, but we can plausibly tie Friday's Texas storms, coming on the heels of another extreme downpour last week to two things going on. Or at least we can use Friday's storms as examples of what can happen under two big picture atmospheric trends.

The most immediate of these is El Nino. That's the periodic warming of the eastern Pacific Ocean we've been hearing so, SO much about. It's one of the strongest ones on record.

Floods sweep through houses near Austin, Texas Friday.
Photo by Kaitlan Ross via Twitter.  
The upshot is during the winter, El Ninos often really supercharge the jet stream along the southern tier of the United States from California to Florida.

Under this regime, that region of the country is particularly prone to strong storms, severe thunderstorms and flooding rains.

This Texas nightmare weather of late could well be the start of this winter stormy pattern in the South. We'll have to wait and see on that, but occasionally, we could well be hearing of nasty storms in the South all the way into March or possibly beyond.

Next, some of you will roll your eyes, but I have to say it. Global warming can take some bad storms and make them worse. The warmer atmosphere with a warmer planet can hold more moisture. Which means downpours can get heavier.

One of the main effects of global warming, say many scientists, would be an increase in extreme precipitation events. What would be a flooding downpour can on many occasions turn into a record or near record inundation.

Obviously, I can't say for sure whether global warming had anything to do with Friday's Texas floods, but we are seeing an uptick in extreme precipitation storms both in the United States and in many other parts of the world.

The trouble with these extreme downpours is they can happen almost anywhere, and they can cause extreme damage, as we saw in Texas yesterday.

I hope climatologists are wrong about the expected further increase in extreme storms in the coming years and decades, but I have no reason to believe they are wrong.

Here's a video taken by a guy in a car swept rapidly down a flooded creek in Texas yesterday. Extremely scary. Thankfully, he was later rescued from a tree:

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