spring 2011 weather floods droughts tornadoes | The Old Farmer's Almanac

Spring 2011: Floods and Droughts

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Most springs bring April showers and May flowers. This year, springtime has brought floods, droughts and a record-breaking number of tornadoes. Oh, dear!

Click to expand. Concentrated rainfall. Source: HPRCC

The problem is that the same forces that gave us the snowy winter of 2010 – 2011 are still here shaping spring. This means that the US has shifted from a very extreme winter to a very extreme spring. The good news is that one of the forces will fade away by summer. Meanwhile, the US and Canada are struggling through a very tough springtime.

What is happening is a crash of two very different air masses. Like any crash, it’s ugly to be caught in the middle. To the west, we have the chilly La Niña – going, going, but unfortunately, not gone. It is encouraging drought in the Central and Eastern southern tier of states. It also encourages cooler air from the west, particularly the northwest.

To the east we have an unusually warm Atlantic Ocean, heating the air above it. This produces a warm wet air mass and when the cold air crashes into it – rainfall. The greater the contrast in the temperatures of the air masses, the stronger the precipitation. Unfortunately the two air masses have been colliding all year.

In winter, this helped to produce major blizzards. In spring, the La Niña is steering moisture away from the Gulf. Instead the air masses have been colliding both around the Midwest and in the Northeast. When this heavy storminess is added to the massive amounts of melting snow, the result is floods.

From one extreme to the other - storms and floods in the North and drought and wildfires in the Southern Plains SOURCE: NOAA

Think of it as concentrated rainfall. It’s as if all the rainfall that would normally fall throughout the Eastern and Central states has been concentrated in one soggy band of misery. The floods then roll down the Mississippi. Meanwhile other portions of the nation, like Texas and the Southern Plains have been left bone dry.

The crashing air masses are like a car wreck – messy and causing horrendous damage.

Is there any good news in this scenario? Only one – scientists expect La Niña to fade away by the end of June.

We actually might have a near normal summer. It would be a relief.