(Des Moines) State Climatologist Dr. Justin Glisan says forecasters are examining various reasons for the exceptionally severe weather pattern this past spring and summer. He says they are examining different things in the Pacific Ocean, such as blobs of oceanic temperatures north of the El Nino region along the tropical Pacific. Dr. Glisan says there were 523 severe wind reports and 238 hail reports. Of those reports, 31 were two inches or above, and 23 reports of wind gusts 75 miles per hour or greater. In 2004, Iowa experienced 100 tornadoes. According to Glisan, the preliminary data shows that Iowa has had 129 tornadoes so far this year, and this number may change as the tornadoes are confirmed.
The peak of tornado activity occurred in May, followed by another increase in June and July. Three of the 129 tornadoes have been classified as EF2 or higher. The highest was the EF4 tornado in Greenfield, with “Doppler on Wheels” measuring wind speeds of 318 miles per hour, about 160 feet up.Dr. Glisan says this is the second-strongest tornado in observational history for the United States and the globe. This massive destructive tornado swept through Villisca, Nodaway, Brooks, Corning, and Greenfield, killing five people and injuring 35 others.
On the bright side, Dr. Glisan doesn’t see this past severe weather season as a trend.
Glisan says the transition from the strong El Nino over the winter months gave us the second warmest winter to potentially a weak La Nina in September and October. The ENSO neutral between those two phases this past spring historically caused a wetter weather pattern driven by thunderstorms, which is what occurred.
