“Tornadoes need warm, moist air interacting with faster, cooler air,” explains Kevin Trenberth of the National Center for Atmospheric Research. “That much scientists know for sure. There’s a lot we understand about tornadoes. They’re tied to thunderstorms, and also require something that will cause rotation to occur, a wind shear.”
Years from now, we may look back and remember April 2011 as the month climate change took hold on the public’s mind. It was very difficult not to hear about, or read about, the weather last month. None of us knew it would build to a crescendo that would be impossible to ignore by the end of the month.
Flooding across the Midwest began in early March across Illinois, Indiana, and Ohio. Copious amounts of snow melt, coupled with the bare beginnings of what was forecast to be a cool, wet spring, had the easily anticipated results.
Tributaries of the larger rivers filled up first. The danger to life and limb is caused, in these situations, not just by raging flood waters, but by the accompanying winds and resultant downed trees.
While the Upper Midwest began sandbagging in February in places like Minnesota and North Dakota, the storm track has followed a more southerly route this year. By late March, FEMA had posted the following message on its website: If you haven’t taken steps to get prepared for a flood, visit Ready.gov today.
Water, water everywhere
The question is, Where the heck is all this water coming from?
In order to answer that, we need to talk about SST’s. That’s Sea Surface Temperatures, for all you landlubbers. Specifically, we need to talk about SST’s in the Gulf of Mexico. The sea surface temperature of the Gulf these days is 1-2.5 degrees Celsius (that’s 2-5 degrees Fahrenheit) warmer than its average temperature.
The atmosphere is warmer, too.
What all this adds up to is warm water being absorbed, in the form of water vapor, by the warmer-than-usual air above it, and transported by the prevailing winds over land. (Be mindful, as you read this article, that water vapor is itself a greenhouse gas.) The four percent increase in atmospheric moisture comes down on us in the form of additional rainfall. It also makes up half the recipe (see introductory quotation) for “how to make a tornado.”
While the jet stream provides the necessary wind shear — the other half of the recipe — most of the time, there is a growing body of evidence that points to La Nina years as being more tornadically “robust” than average.
Previous historic La Nina tornado years have included 1974, 1999, and 2008. The mechanism is not yet well understood, but the historical trend continued with April’s outbreak. The current La Nina, which began last summer, caused havoc over the winter of 2010-2011. Temperatures were extremely cold, and snow and ice were widespread.
To what degree the melting Arctic ice and snow of summer 2010 provided moisture for this weather is unknown.
Couple this with the 200 mph winds of an EF-5 tornado, like the one that touched down in Tuscaloosa in April, and the outcome is astonishing.
All of us have seen footage of tornado damage in television reports. This time, however, there was a difference. The always-sad spectacle of people’s possessions strewn about for block after block was compounded by the distinct impression that all the rubble appeared to have been put through a food processor. All that was left was little bits and pieces, like the shards found at an archaeological dig. Where on earth will they put all that debris? The ready solution, of course, would be to burn it all …
When all else fails: Local resilience
Where the money will come from to help people recover from disaster after disaster is food for unhappy thought.
Governor Perry of Texas, ironically a small-government advocate, is angry that the current administration in Washington has not been forthcoming with offers of help for his beleaguered state, currently at the mercy of fires which have been burning for months.
Insolvent state and national governments are in no position to help citizens struggling with an increasingly unpredictable Mother Nature. It turns out warmer and wetter is a bad combination. As things stand now, we cannot honestly expect our climate to become less violent, and that places us in a real economic bind.
The folks in Washington work very hard at not seeing the handwriting on the wall. Even if they saw it, they no longer have the money to do anything about it.
That’s why it has become even more important for each of us to do what’s necessary, in order to prepare for the next natural disaster. A good place to start would be visiting the FEMA website. If you belong to a Transition effort, the book Are You Ready?, published by FEMA, might be an excellent starting point for some very useful discussions.
Resilience and self-reliance go hand-in-hand, and you can help each other take some big strides in the direction of surviving whatever comes next.
Think about Tuscaloosa, then start planning.
–Vicki Lipski, Transition Voice
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