Iowa saw a massive outbreak of tornadoes, including at least eight confirmed tornadoes in north Iowa, during the mid-December derecho, which was very rare.
Weather experts continue to study that system as well as the series of over a dozen tornadoes that touched down in Iowa earlier this month that claimed seven lives and damaged or destroyed dozens of houses.
Meteorologist Dennis Todey, director of the U.S.D.A.’s Midwest Climate Hub in Ames, says the strength of the tornadoes on March 5th was very unusual, including a pair of EF-2s, an EF-3 and an EF-4.
Todey says small tornadoes in March are not too much of a surprise, but something of this nature and, that there were several of them, is really more than we want to see at this point. He adds he’s unsure if this is a signal of more frequent early-season severe weather just yet, but it is also an example of a typical spring kind of thing where you get some severe weather ahead of a big system and then cold air and snow behind it.
Temperatures in parts of Iowa March 5th were in the 60s and 70s, then the late afternoon storm brought tornadoes and hail, followed the next day by highs only in the 20s and 30s and several inches of snow. Todey says that clash of large masses of warm and cold air is textbook for tornadoes.