April 2011 Tornado Outbreak

From noaa.gov 312 tornadoes from 4/ EDT to 4/ EDT About 340 killed in this time period The Tuscaloosa-Birmingham tornado had a width up to 1.5 miles and a track 80 miles long. It killed 65 people.

From noaa.gov These are the most fatalities from a single tornado in the United States since May 25, 1955, when 80 people were killed in a tornado in southern Kansas with 75 of those deaths in Udall, Kansas. 2 EF-5’s 11 EF-4’s

From Birmingham NWS Track map: The Hackleburg tornado was an EF-5 “THE MAIN INDICATORS OF HACKLEBURG HAVING EF-5 DAMAGE IS THE TOSSING OF VEHICLES UPWARDS OF YARDS…”

From Birmingham NWS The Tuscaloosa-Birmingham tornado was a high end EF-4 “THIS TORNADO WAS PRODUCED BY A SUPERCELL THUNDERSTORM THAT BEGAN IN NEWTON COUNTY MISSISSIPPI AT 254 PM CDT...FINALLY DISSIPATING IN MACON COUNTY NORTH CAROLINA AT APPROXIMATELY 1018 PM CDT. SO...THIS SUPERCELL EXISTED FOR ABOUT 7 HOURS AND 24 MINUTES...TRAVELING APPROXIMATELY 380 MILES PRODUCING SEVERAL STRONG TO VIOLENT TORNADOES ALONG THE WAY. ”

From Birmingham NWS What is a supercell?

From Huntsville NWS Hackleburg EF-5 continued… “A 25 FOOT SECTION OF PAVEMENT WAS SUCKED UP AND SCATTERED. CHUNKS OF THE PAVEMENT WERE FOUND IN A HOME OVER 1/3 MILE DOWN THE ROAD. ”

From NOAA.gov 4_summary.html# 4_summary.html# The event WAS well-forecast. Days ahead in general Minutes ahead in specific

From NOAA.gov oes-climate-change-2011_n_ html oes-climate-change-2011_n_ html A summary and discussion of the possible impact of climate change No obvious connection Number of most violent tornadoes has NOT increased Increase in low-level hot, humid air ???