EF1 tornado in St. Louis County, Minnesota

A supercell thunderstorm formed halfway between Meadowlands and Canyon, MN, between 4:35 to 4:40 PM on Thursday, September 19, 2024. As the strong thunderstorm continued to show potential for producing a tornado, the National Weather Service office in Duluth, MN, issued a Severe Thunderstorm Warning at 4:44 PM for this storm. The strong storm moved eastward over unpopulated marshes immediately north of Lake Nichols Road about 4 miles north-northwest of Canyon, MN, by 5:00 PM. Meteorologists at the National Weather Service issued a Tornado Warning for this storm at 4:55 PM as early signs of tornadic development appeared on radar, and a short time later a tornado was confirmed by trained spotters and law enforcement. Visible tree damage from the tornado, estimated to have begun at 5:05 PM CDT, was first observed on the west side of US Highway 53 about 4.5 miles south of Cotton, MN, with pine trees snapped at the base. The tornado continued to move northeastward to uproot trees along Three Lakes Road about one-half mile east of the U.S. Highway 53 intersection. The storm began to move more north-northeastward so the tornado track shifted more northward with the most widespread surveyed damage seen along Bug Creek Road about 2.5 miles east-southeast of Cotton, MN. Over 50 pine trees and numerous clusters of aspen trees were observed to be snapped at the base and/or uprooted, estimated to have occurred at around 5:15 PM. A few still-standing pine trees had metal sheets lofted and wrapped around them. Minor to moderate structure damage was reported by two property owners along Bug Creek Road before the tornado passed northward over the Whiteface River. Towards 5:18 PM, the tornado began to weaken and finally lifted off the ground. The last uprooted trees, 4 aspen, were last observed at the intersection of Comstock Lake Road and Melrude Road, 2.7 miles east of Cotton, MN. In total, the tornado was on the ground for a total of 5.9 miles and for around 13 minutes. The damage rating from the NWS Duluth Storm Survey team resulted in an EF-1 rating with winds estimated at 105 mph. There were a total of two Tornado Warning in effect from 4:55 PM to 5:45 PM for this tornadic supercell thunderstorm.

A cold front moved through north-central Minnesota in the late afternoon hours on Thursday, September 19, 2024. Out ahead of the cold front in northeast Minnesota, discrete severe thunderstorms began to form in far northeast Minnesota along the US Hwy 53 corridor around 4 PM CT. The first Severe Thunderstorm Warning was issued at 4:15 PM for parts of far northeast St. Louis County and northwest Lake County as the severe storm moved northeastward around 30 mph. By 4:55 PM, conditions within a different severe supercell thunderstorm warranted the first Tornado Warning of the evening to be issued for central St. Louis County around the communities of Cotton and Canyon, MN. Between 5 and 5:30 PM that evening, multiple additional Severe Thunderstorm and Tornado Warnings were issued along and east of US Hwy 53 and along the I-35 corridor into east- central Minnesota. The cold front continued to move eastward through the early evening hours on the 19th, with storms beginning to enter Douglas and Burnett Counties in northwest Wisconsin towards 6 PM as low-level funnel clouds were reported by law enforcement and trained weather spotters. Hail up to 1.5 inches in diameter was reported from the strongest thunderstorms, but in very localized reports. As the air mass began to cool and stabilized in the mid-evening hours, the threat for additional tornadoes began to wane and the strongest thunderstorms were limited to the Twin Ports and across northwest Wisconsin. As the cold front entered northwest Wisconsin by late evening, activity subsided to only showers and general thunderstorms with no additional impacts reported overnight. In total, eight Tornado Warnings, nine Severe Thunderstorms Warnings and two Special Marine Warnings were issued for this severe weather event. The Cotton/Canyon Tornado is the only confirmed tornado from this severe weather event at this time. While funnel clouds were reported with several other storms, there is currently no evidence that any of the other storms produced a tornado that reached the ground and produced damage.