Warmest on winter on record for Upper Midwest and Great Lakes

July 06, 2024

From the northern Plains to the Great Lakes, February is typically a time for winter revelry, set against a landscape of deep snow and iced-over waterways. But this year, snow is absent, ice is dangerously thin, and many cities are experiencing their warmest winter on record.

Across most of Minnesota and Wisconsin, average temperatures are 10 degrees or more above average for the season. Ice cover over the Great Lakes is at record lows. Wisconsin even observed its first February tornado on record, fueled in part by the warmth.

The “lost winter” is affecting commerce in the region: Ice fishing opportunities are limited, ski areas are struggling, and wintertime events dependent on snow can’t proceed.

Winter has a month or two left, but the forecast offers little promise for sustained cold. The exceptionally warm winter fits into a long-term trend toward milder winter weather, driven by human-caused climate change.

The warmest winter on record so far

Most of the Great Lakes region is enduring its warmest winter on record, including much of Minnesota, Wisconsin, Michigan and parts of surrounding states. Many additional locations in the Northeast and Mid-Atlantic are also experiencing one of their warmest winters. The warmth expands into central Canada. The temperature in Winnipeg has been at least 5 degrees Celsius (9 Fahrenheit) above normal for 24 straight days.

An examination of the Accumulated Winter Season Severity Index (AWSSI) from the Midwestern Regional Climate Center classifies the winter severity as “mild” — the tamest level on its five-point scale — from the northern Plains to the Mid-Atlantic. Fargo, N.D.; International Falls, Minn.; Minneapolis; Sault Ste. Marie, Mich.; Toledo; and Syracuse, N.Y., are among the cities experiencing a record mild winter.

Data logged by the Southeast Regional Climate Center shows just how abnormally warm it has been in certain cities:

Fargo — 13.8 degrees above normal
Minneapolis — 10.7 degrees above normal
Green Bay, Wis. — 9.5 degrees above normal
Alpena, Mich. — 8 degrees above normal
Binghamton, N.Y. — 7.8 degrees above normal
Caribou, Maine — 7.1 degrees above normal

“Milwaukee has been above freezing [for highs] the majority of the winter (67/75 days), and low temperatures in Milwaukee are nearly 10 degrees above normal,” Chris Vagasky, manager of Wisconet, a network of weather stations in Wisconsin, wrote in an email.

Minneapolis has seen a record 23 straight days with high temperatures above freezing; it’s so mild that there have been reports of ticks at a time when normal highs are in the mid-20s.

Meteorological winter — defined as December to February — has about “two weeks to go, but so far this month the state is running an astounding 20 F above normal (based on preliminary data),” Steve Vavrus, state climatologist of Wisconsin, said in an email Monday. “I would say it is likely that this winter will go down as Wisconsin’s warmest.”

Missing ice

Considering the mild weather, it’s no surprise that ice coverage across the Upper Midwest and Great Lakes basin is at historic lows. As of Tuesday, Great Lakes ice coverage was at less than 3 percent.

“For the date, it’s the lowest ice cover ever seen,” said Bryan Mroczka, a scientist with the Great Lakes Environmental Research Laboratory.

Modern ice records for the Great Lakes date to 1973, when monitoring from weather satellites began. Since then, ice cover has been on a downward trend.

“On average, there has been a 5 percent decrease in ice per decade. It is down 25 percent since the 1970s,” Mroczka said. “The Great Lakes have lost about 27 days of ice cover, almost a month.”

Although warmer winters can still feature Arctic outbreaks, human-caused climate change is reducing the frequency, duration and intensity of extreme cold spells. This year’s El Niño climate pattern is amplifying the warmth, but Mroczka said unusually low ice years have also occurred without El Niño.

Snow problems

Snow is also extremely lacking across most of the northern tier of the Lower 48. Large parts of the Upper Midwest, Great Lakes region and Northeast are running 20 inches or more below average.

“Nashville has received more snow this winter than Minneapolis,” Vavrus said. Indeed, snowfall in the Music City reached 7.6 inches in January, compared with 7.3 inches in Minneapolis thus far.

Minneapolis’s snow total to date is the lowest on record through Feb. 13 and more than two feet below average.

To the east in Marquette, Mich., the 72.6 inches of snow so far this season may sound like a lot, but the average to date is 127 inches.

There has been no snow on the ground in Burlington, Vt., for the first 13 days of February for the first time in records that date to 1895. The northern New England city has received 27.9 inches so far this winter, compared with the norm of 54.7 inches.

Why winter’s absence matters

The absence of snow and ice is taking its toll in regions that rely on them as a source of revenue, exercise and fun. It has forced the cancellation of numerous events around Minneapolis, including the final weekend of the U.S. Pond Hockey Championships, the Burnsville Polar Fest and the Ice Palace of Minnesota. In northern lower Michigan, the Black Lake winter sturgeon fishing season was canceled. The University of Wisconsin Union’s Winter Carnival was pared back because of the lack of ice and snow.

Agriculture is also being tested. As one example, grape vines are appearing like they normally do in March or April. This could make them more vulnerable to damaging freezes in the weeks ahead.

And in a region where winter sports are a way of life, thin ice poses a danger.

“Anybody doing activities on the ice needs to be extremely careful and always check the conditions before going,” Vagasky said.

Mroczka added that the lack of near-shore ice on the Great Lakes is a concern when late winter and spring storms strike because the ice acts as a buffer against coastal waves. Without ice, erosion increases, and so does the risk of damage to infrastructure and property.

Winter severity is waning, but don’t totally count it out

Midway into February, it’s premature to conclude that winter won’t attempt a comeback. Ice on the Great Lakes tends to peak in late February or early March, as does snow depth in the region. In some years, punishing cold and snow have struck as late as April and May.

The short-term forecast calls for a few cold days late this week before generally mild weather in the 10 days that follow. Beyond that, the forecast is uncertain.

But looking ahead to future seasons, the outlook isn’t promising for winter weather lovers. The season is dramatically shrinking in length, and average temperatures are rising.

Every winter won’t necessarily look like this one, as there can be large year-to-year variability. Just last winter, many parts of the Upper Midwest and Great Lakes observed above-average to record snowfall, for example. However, the trend toward milder and shorter winters means seasons like this one will probably become more common.

According to the Minnesota Department of Natural Resources, the winter season has warmed two to three times faster than summer.

“More and more frequently, Arctic outbreaks are shorter in duration,” Mroczka said. “These lakes are massive and need a long, sustained pattern of cold weather to get them to ice up.”

“Cold is still brutal at times every winter but just doesn’t last long,” he added.

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