National Weather Service United States Department of Commerce


A strong area of low pressure brought heavy snowfall and very strong winds to much of the Northland starting on Wednesday the 23rd and lingering into Thursday the 24th. This storm was unique in that widespread blizzard conditions occurred across the upper Midwest, including areas from the Brainerd Lakes east towards the North Shore, Twin Ports, and Interstate 35 corridor with many observed wind gusts between 50 and 70 mph. Very strong frontogenesis occurred along a trowal axis that extended across much of northern Wisconsin west into Minnesota. Warm air advection caused temperatures across most of northwest Wisconsin and east-central Minnesota to rise above freezing and produce mixed precipitation for several hours during the day. As the cold front gradually moved east, temperatures very quickly dropped and caused treacherous road conditions as mixed precipitation changed over to snow. Narrow bands of heavy snow set up over the Brainerd Lakes northeast towards the Iron Range during the early morning and early afternoon, and then translated east towards the Twin Ports, North Shore, and Interstate 35 corridor. The heavy snow bands coincided with the strong mid-level frontogenesis, which also produced very strong northwest winds that caused the widespread blizzard conditions. A maximum gust of 70 mph was recorded at the Bay of Grand Marais during the height of the storm. Damage was reported to buildings and other infrastructure, in addition to some power outages and widespread whiteout conditions that made travel difficult if not impossible.

As the cold front swept rapidly eastward, bitterly cold air moved into the region and led to the development of a topographically-forced gravity wave during the night of the 23rd that dropped several more inches of snow from Two Harbors to Superior to Holyoke. The highest snowfall report was 13 inches of snow in Holyoke under this band. Further east, lake-effect snow continued into Thursday along the South Shore. Gile, Wisconsin, saw 18.5 inches of snow before lake-effect snow tapered off Thursday evening.

December 23-24, 2020, Snowfall Map
Snowfall Totals for the December 23-24, 2020 Storm
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