Enough snow and precipitation to double seasonal totals in some places!
After a warm winter that was largely devoid of significant snowfall, a powerful winter storm lashed Minnesota with heavy snow, slush, rain, a few thunderstorms, and strong winds from late Saturday March 23rd into Wednesday March 27th, 2024. This major storm produced multiple waves of precipitation, leading to by far the largest snowfall event of the 2023-24 winter, and a season's worth of precipitation in some areas.
A highly energized disturbance aloft with winds of over 150 mph helped produce a large surface low-pressure system over eastern Colorado, which is a common breeding ground for major winter storms in the Upper Midwest. Despite the strong winds aloft, the forces moving the system along were somewhat slower, and so rather than affecting the region for a total of about one day, as is the norm for "Colorado Lows," this storm spent about one full day approaching the area, one day passing through, and one day moving away. As a result, Minnesota had a much longer exposure to precipitation than is typical with winter storms.
Mostly light snow began on Saturday night in southwestern and southern Minnesota, but by Sunday morning, snow was intensifying in southern Minnesota along a warm front that extended from the low pressure in Colorado. That snow spread northward in waves throughout the day, with the heaviest starting near the Iowa border in the late afternoon, reaching the Twin Cities area between 8 PM and midnight, and continuing northward into Monday morning. Snowfall rates approached 2 inches per hour at times, and by morning, a large part of Minnesota had received anywhere from four to 12 inches of heavy, wet snow.
Warm air worked into Minnesota from the south as well, and rain quickly followed the heaviest snow bursts, leading to slushy conditions across southern and eastern parts of the state by Monday morning.
Through Monday, waves of scattered rain showers with isolated thunderstorms continued in southern and eastern Minnesota, while snow with mixed precipitation continued falling in northern and western areas. Monday represented a relative lull in the precipitation, sandwiched between the heavier and more continues snow from Sunday, and a batch of heavy rain, mixed precipitation, and snow that moved back into Minnesota Monday night and Tuesday as the low-pressure center passed from western Iowa into northern Wisconsin.
The final waves of precipitation Monday night and Tuesday were nearly as intense as what fell Sunday and Sunday night, but with much stronger winds out of the northwest, which caused temperatures to drop sharply. Rain turned to sleet, slush, and snow, with heavy snow with visibility 1/4 mile or less reported for the first time this winter at the Twin Cities airport. Winds gusting over 30 mph (over 40 mph in open areas) caused blowing, drifting and near-whiteout conditions, open areas. An additional 3-6 inches of snow fell during this time across the Twin Cities and nearby parts of central and eastern Minnesota. Over the northeastern quarter, the snow was heavier and longer-lasting, leading to an additional six to 14 inches of accumulation.
On Wednesday, cold air aloft moved into the region, providing enough instability to generate isolated snow squalls that affected parts of Minnesota, with generally light accumulations, though International Falls picked up an additional 4.7 inches of snow.
Storm Totals - Snow
This was by far the largest snowstorm of winter for Minnesota, and was comparable in many ways to the large, multi-day storms that affected the state during the stormy 2022-23 winter (December 13-16, 2022; January 2-5, 2023; February 21-23, 2023).
Over 60% of Minnesota received six inches of snow or more, with about a quarter of the state receiving at least a foot. Some of the highest totals were near Duluth and Brainerd, where observers with the National Weather Service and with the CoCoRaHS network reported over 20 inches of storm-total accumulation, including a report of 26.4 inches in the hills around Skyline Parkway on the west side of Duluth. The National Weather Service Cooperative observer northwest of Two Harbors reported 21.2 inches, with other observers in the area reporting over 18 inches of snow. The airport at Duluth received 17.7 inches, International Falls received 13.8 inches, and at the Twin Cities International Airport, the storm total was 12.1 inches, with a daily record 8.2 inches falling on the 24th. The snow from this system equaled -- or in cases like Brainerd -- exceeded snowfall totals from the entire snow season up to that point, which illustrates the unusual size of this storm given the season during which it occurred.
Precipitation
Heavy snow is always the big attention-getter during winter, but this system was equally significant for its total precipitation. The southeastern half of Minnesota received at least 1.5 inches of total precipitation, and the southeastern quarter of the state received over two inches, with some areas approaching three. This event, therefore, erased the precipitation deficits that had developed since early winter in some areas.
Rare Combination of Heavy Snow AND Heavy Rain
Areas in and near the Twin Cities, including the MSP airport, did something unusual: they received both a foot of snow or more and at least one inch of rain, from the same storm. It is difficult to track down historical occurrences of this type of pairing, but we know it is rare. It certainly has not occurred in the Twin Cities during the past 40+ years. During the infamous Halloween Blizzard of 1991, some communities in far southern Minnesota received well over an inch of rain, and then a foot of snow. Something similar occurred over a larger area during the great Armistice Day Blizzard on 1940. These were both historic, generational events. The storm of March 2024 is not on their level, but its meteorological feats were rare indeed!
March 28, 2024