Updraft® - Minnesota Weather News

Seeds of devastating Chicago derecho started Monday in Minnesota

Chicago National Weather Service office surveying 29 damage swaths

Derecho approaching Chicago
Derecho approaching Chicago Monday evening
National Oceanic and Atmospheric Administration

A powerful derecho ripped across Iowa and through the Chicago area Monday into Monday night.

The system produced a swath of wind damage. Winds as high as 97 mph were recorded in eastern Iowa as the storms tore through.

Tuesday the Chicago National Weather Service office sent out six survey teams to assess as many as 29 damage swaths in the Chicago area.

Chicago tornado
Damage paths in Chicago Monday night
Chicago National Weather Service office

The storm clusters produced severe weather Monday morning in central and southern Minnesota.

Wind damage occurred in central Minnesota where a semitrailer was flipped by high winds.

The frontal system slid south into Iowa Monday afternoon. That’s where new storms exploded and congealed into a massive derecho that produced wind damage in Iowa before racing east toward Chicago.

The infrared loop is astounding.

Multiple squall line (quasi-linear convective system) rotation tracks swept through the Chicago area last night. I’ve never seen anything quite like this one:

Early survey results by the Chicago National Weather Service office have already found multiple tornado damage paths in the Chicago area:

This looks like a truly historic storm for eastern Iowa through the Chicago area. And the seeds of this derecho started in Minnesota Monday morning.