Spring 2011 U.S. Climate Extremes
National Oceanic and Atmospheric Administration
National Climatic Data Center
- Introduction
- Tornadoes
- Flooding
- Drought and Wildfire
- Synopsis
- Full Report
Note: Data in this report are compiled from preliminary statistics
Introduction
The spring (March-May) of 2011, particularly April, brought extreme weather and climate events to many parts of the United States. Tornadoes, flooding, drought, and wildfires ravaged many parts of the country during the period, and each of these extremes broke long-standing records and have been compared to the 'worst such cases' in history. While similar extremes have occurred throughout modern American history, never before have they occurred in a single month. According to the Storm Prediction Center (SPC), there were 751 tornadoes during April alone, and the confirmed number of tornadoes surpassed the all-time monthly record of 542 tornadoes set in May 2003. Record rainfall along the Ohio River Valley, punctuated with snowmelt across the upper Midwest, caused record flooding along the mid and lower Mississippi River, with water levels surpassing the historic floods of 1927 and 1937. Above-normal precipitation and vegetative growth during 2010, followed by dry and windy conditions the first five months of 2011, created ideal wildfire conditions across the Southern Plains where millions of acres of land burned. According to the U.S. Drought Monitor (USDM), the same region experienced Extreme-to-Exceptional [D3-D4] drought following consecutive months that were record to near-record dry.April brought an active weather pattern across the contiguous U.S., with strong storms moving through the center of the country, tapping into moisture from the Gulf of Mexico as they matured across the mid-Mississippi Valley. These storms caused widespread severe weather across the Southeast and widespread heavy precipitation across the Ohio Valley. Both the number and magnitude of the severe weather events, as well as the amount of precipitation across the Ohio Valley, broke all-time records, according to preliminary data. Meanwhile, the storm track essentially blocked Gulf of Mexico moisture from entering the Southern Plains.
No comments:
Post a Comment