Did you think last year’s weather was weird? Now it’s official. You were right!
Last December it was reported that the US had a dozen billion (yes, billion) dollar weather disasters in 2011. It was a record! Now, whoops, it has been announced that the government underestimated how bad the year really was. There were really 14 billion-dollar disasters. Wow!
Hot, miserable and expensive! The Southern Plains and Southwestern heat wave was the most expensive weather disaster of 2011. Source: NOAA
Why was the weather so record-breaking? Does it look like we will have the same problems with weather this year?
First, let’s look at what the disasters were. They were:
- The Groundhog Day blizzard had snow covered 49 of the fifty states.
- Six Midwest/Southeast tornado outbreaks—From April to June, the nation had 1,200 tornadoes that killed more than 500 people.
- The Southern Plains/Southwest drought and heat wave—This drought and heat wave was the nations’ single most expensive disaster, costing up to $10 billion.
- The Texas, New Mexico, Arizona wildfires—From spring to fall, the three states went up in flames.
- Flooding—Two huge floods, one along the Mississippi and the other along the Missouri and throughout the upper Midwest, swamped both the US and parts of Canada.
- Hurricane Irene and Tropical Storm Lee—The one-two punch of these storms created two billion dollar events that flooded the East.
- Rockies and Midwest “weather event”—Last week NOAA added a nasty swirl of July weather that poured off the Central Rockies onto the Plains to the list
What a year! 2011 had more billion-dollar disasters than any other year. 2005, with Katrina, was the most expensive year. Source: NOAA
So why was the weather so awful? There are a number of reasons, but the overriding cause was that there was an extreme contrast between the abnormally cold polar air mass and the steaming tropical air mass. The polar air surged unusually far south and hit the warm marine air from the Gulf and Atlantic. At the same time, the Atlantic was abnormally warm, heating the air flowing inland from these waters.
When the two extremely different air masses crashed into each other, it was like a car crash – messy and a lot of damage.
The good news is that the Atlantic/Gulf is somewhat cooler and the Arctic air patterns are pinned further north. Expect interesting weather, but not be as exciting or expensive as last year.
Did any of these events that affect you? Share your story and let’s gratefully say goodbye to 2011.
Evelyn Browning Garriss, historical climatologist, is a longtime writer for The Old Farmer's Almanac. She is also editor of The Browning World Climate Bulletin  and has advised farmers, businesses, and investors worldwide on upcoming climate events and their economic and social impact for the past 21 years.