The Week in Severe Weather: Where Have All the Tornadoes Gone?

The United States tornado season is getting off to an unusually slow start this spring, due to the lower-than-normal temperatures that have persisted across much of the country over the last few months.

According to Aon Benfield’s weekly natural disasters report on Friday, only 20 tornadoes measuring EF-1 or higher on the storm strength scale have been recorded so far this season, the lowest reading for that figure in at least 62 years of official record keeping. Usually, forecasters can expect to see at least 150 tornadoes by this point in the year. In all, no tornado-related fatalities have been reported so far this season – the longest stretch to start a year since 2002 – and it has been 158 days since an EF-3 tornado has touched down in the U.S., the fourth-longest streak on record for that measure.