Are La Nina and global warming behind the extreme tornado activity?
Tornadoes have been descending from angry skies with a frequency that may become unmatched in official records of April twisters. Cities, small towns, rural hamlets -- even international airports -- have suffered severe damage. The atmosphere has been behaving like an unruly teenager, with 275 tornadoes recorded so far this month.
Another contributor to the recent severe weather is an unusually warm Gulf of Mexico, where sea surface temperatures are running 1 to 2.5 degrees Celsius above average. The Gulf is the main moisture source for storm systems as they move east from the Rockies, and the additional moisture is helping to fuel thunderstorm development.