Smoke plumes seen on radar loop from Duluth late afternoon on Monday May 12, 2025. Stationary, "streaming" echoes ( three to north and one to south of radar site) are particulates in smoke plumes from wildfires.
Radar loop courtesy of College of DuPage; data from NOAA/National Weather Service
A hot, dry air mass overspread Minnesota beginning on Saturday May 10th, with record high temperatures and an outbreak of wildfires in parts of the state.
A warm, sunny, and dry pattern had dominated Minnesota's weather since May 2nd or 3rd, but a much hotter and drier air mass moved in over the weekend of the 10th and 11th, as winds from the southwest increased along the gradient between low pressure in Montana and high pressure over the northeastern US.
Saturday May 10th was warm and sunny in most areas, but hot in the west and southwest, with temperatures reaching the upper 80s to near 90 degrees F.
The heat reached its greatest intensity on Sunday May 11th, as winds increased and relative humidity dropped into the 15-25% range. The highest temperatures exhibited an atypical, geographically inverted pattern, with far northern Minnesota coming in as the hottest part of the state. International Falls reached a maximum temperature of 96 F, which shattered the old daily record of 83 F, and became the highest temperature ever recorded so early in the season at that station. St. Cloud, the Twin Cities, and Duluth all set daily records, at 93, 90, and 87 F, respectively.
On Monday May 12th, the heat continued, at slightly lower intensity, though with even drier air in some areas. Relative humidity of 10-20% was common throughout Minnesota. International Falls and Duluth broke daily high temperature records, with 90 F and 86 F.
The excessively dry heat, combined with gusty winds and emergent or dormant vegetation, led to high risk for wildfires. One fire, named the Camp House Fire, damaged structures and forced evacuations near Brimson in St, Louis County on Sunday. By Monday another fire formed about 10 miles away near Jenkins Creek, and the Duluth radar showed the plumes of four separate fires--three in St. Louis County and one in eastern Pine County near the border with Wisconsin.
This story is ongoing.
May 12, 2025
KAB