Natural Disasters: Severe Weather: Tornadoes, Snowstorms, etc.

Tornadoes devastated parts of the Midwest in Spring 2011.

Radar sequence of tornado supercell thunderstorms that tracked from western Mississippi into southwest North Carolina. (Brian Tang) National Center for Atmospheric Research. "Radar montage of the most impressive supercell from [Wednesday’s] massive tornado outbreak. This cell traveled about 450 miles and lasted over 8 hours! It also was responsible for the large, violent tornado that caused the destruction in Tuscaloosa, [the north] side of Birmingham, and a number of other cities.”

"The National Weather Service reported this morning that the tornado spawned by this supercell from Tuscaloosa to Birmingham was on the ground for 80 miles and reached high-end EF-4 intensity (winds to 190 mph)."

"Almost all of the radar echoes for this storm display the tell-tale hook shape, indicative of intense rotation and tornado production."

Image credit: Matt Daniel

EF4 (190 mph winds) tornado damage in Pleasant Grove, Alabama on April 27, 2011.

The Fujita scale (F-Scale), or Fujita-Pearson scale, was a scale for rating tornado intensity, based primarily on the damage tornadoes inflict on human-built structures and vegetation. It has been replaced by the Enhanced Fujita Scale (2007), a much more precise and robust way to assess tornado damage.

http://www.spc.noaa.gov/faq/tornado/ef-scale.html