The National Weather Service surveyed storm damage in Brookfield on Wednesday and determined it was caused by a macroburst.
The macroburst had maximum wind speeds of 100 to 110 miles per hour, according to a statement from the weather service. It impacted an area of land two and a half miles wide and five miles long.
A macroburst can cause more damage than tornadoes because of the "size and scope of the macroburst," according to National Weather Service experts.
The hardest hit area in Brookfield is the Candlewood Shores area where a number of trees were uprooted.