Wisconsin saw more severe thunderstorm, tornado and flash flood warnings in the first three weeks of April than in any other month in the last four decades of available data, more than a month before the usual peak of the severe weather season.
Wisconsin had 289 warnings as of the morning of April 22, according to National Weather Service data shared by the Wisconsin State Climatology Office. That compares to 264 in June 2005, 262 in July 2006, 258 in June 1998 and 253 in June 2008. June and July usually have the most severe weather each year, said Amanda Latham, climate outreach specialist with the climatology office.
“So far this month, we have packed about 70% of our annual average severe weather activity just into this month,” she said. “It’s just been a wild month, and it also hasn’t been confined to one area of the state. The entire state of Wisconsin has been seeing some sort of severe weather impact.”
Last week was the state’s Severe Weather Awareness Week. While state climatologist Steve Vavrus said the awareness campaign is scheduled to precede severe weather season, this year Wisconsin saw powerful thunderstorms, tornadoes, large hail, flash flooding and damaging winds across the state during the week.
A record-setting start to the severe weather season doesn’t necessarily mean the next few months will see more severe weather than normal, Latham said, but the records for April are still alarming. Wisconsin has averaged about 23 tornadoes per year. Last year, there were 39. This month, there have been at least 25, she said.
There’s some randomness and bad luck behind the recent storms, Vavrus said, but climate change could also be playing a role here: Wisconsin is experiencing more of the warm and humid air that can lead to severe weather, extending the normal season back into April and as late as September or October.
The United Nations Intergovernmental Panel on Climate Change’s Sixth Assessment Report in 2021 noted that the human-caused rise in greenhouse gases increased the frequency and intensity of extreme weather events worldwide.
“I do think that there is certainly a suggestion that climate change is playing a role. We saw that in an extreme way a couple of years ago when we had the first ever documented tornadoes during the month of February in Wisconsin,” Vavrus said.
Latham said she looks at trends and data over time because it’s hard to attribute one specific event to climate change.
“We’re seeing severe weather season spread into spring and also into fall, and a lot of that has to do with how warm our springs and falls have become,” Latham said. “As we start to get warmer earlier in the spring, that means we’re adding more energy into the atmosphere, more energy that can fuel stronger storms.”
As severe weather begins earlier and becomes more damaging, cities and counties are starting to incorporate data from the climatology office when they make their five- or 10-year plans, Latham said. Places are now considering the effects of flooding or wind damage in ways they didn’t before. Municipalities might dig different culverts or construct buildings in new ways to make them more storm-resistant.
Vavrus has been struck by how long the storms lasted and how widespread they were. Often, he said, severe storm outbreaks are concentrated within a single day or evening. But recent storms kept hitting over the course of several days and reached all across the state.
Vavrus said that the fact that the storms were so widespread and affected so many people may mean that more residents will take future warnings seriously.
“This event may be a bit different than some severe weather outbreaks where it was very localized and short-lived,” Vavrus said.
Latham encouraged Wisconsinites who escaped the effects of recent storms to try to put themselves in the shoes of others who are dealing with home or car damage, or worse, when thinking about how they would react to future warnings of severe weather.
“Unfortunately for some of those people, it won’t hit home for them until it really hits home for them,” she said.
By Jonah Beleckis for the Wisconsin Independent.
Broadcast version by Judith Ruiz-Branch for Wisconsin News Connection reporting for the Wisconsin Independent-Public News Service Collaboration
