On Sunday night into Monday morning, a cluster of strong to severe thunderstorms moved across north central Upper Michigan. These storms became particularly intense near and over parts of Ishpeming, where many trees were uprooted or snapped. A storm survey was conducted by the National Weather Service to determine impacts and wind speeds from the storm. It was determined that some isolated areas saw 60-70 mph winds, while most other areas of Marquette County were hit with 45-60 mph winds.
Below are radar images taken from our radar in Negaunee Township. You can see that the storms were stronger when looking at the image on the left, which is reflectivity, and comparing that with the image on the right of doppler winds (green is air moving toward the radar, or the black down in the middle of the image, and red is air moving away from the radar). The heavy rain in the thunderstorms helped force some of that faster moving air aloft to the ground, which caused widespread strong winds and isolated pockets of severe winds across Marquette County.
One of the harder hit areas was around the Wawonowin Golf Course 5 miles west of Ishpeming and just south of M28. At the golf course, 43 trees were uprooted or snapped, some of which were healthy softwood trees around 2 feet in diameter. This is the primary area surveyed that had 60-70 mph winds and where the most tree damage was observed. Just up the road from the golf course was a mobile home park along M28 that saw slightly weaker winds but still saw a few trees fall, some on houses and vehicles. Below are pictures from these areas:
The final location surveyed today was south southwest of Ishpeming in the area of South Angaline, Salisbury and Terrace Streets, where a few trees and tree branches were uprooted or snapped. At this location, a tree branch fell on a car, causing damage to the rear of the vehicle. Winds are thought to have been 50-60 mph at this location. See pictures below:
We at the National Weather Service wish to thank those who provided us with critical information during and after the storm.