Dramatic temp plunge, snow clamp an icy grip on northern U.S.

Temperatures crashed by dozens of degrees in portions of the northern and central Plains as snow and wind whipped across the region at midweek — and forecasters say that dangerous conditions could develop as temperatures take a freefall across the Midwest into Friday night.

Marginally cold conditions have swooped in following storms in the Midwest so far this winter, but the current temperature plunge sweeping across the region has really sunk its teeth in.

Actual temperatures took a freefall to as low as 30 to 10 degrees below zero Fahrenheit in the Dakotas, northwestern Iowa, much of Minnesota and northwestern Wisconsin on Thursday morning.

Actual temperatures centered on the midwestern United States at 10 a.m. EST Thursday. Image by AccuWeather

By Thursday morning, temperatures in Minneapolis dropped 42 degrees, falling to minus 10 degrees.

In Des Moines, Iowa, actual temperatures plummeted from 35 above zero at 4 p.m. EST Wednesday to 10 below zero at 9 a.m. Thursday.

Many schools across Iowa, including Des Moines Public Schools, and Minnesota had two-hour delays due to frigid conditions on Thursday, and some even closed, such as Cedar Rapids Schools.

Minneapolis and St. Paul public schools did not delay Thursday due to their threshold for delaying schools being 35 below zero F, which was not met.

In Chicago, the morning rush hour began with temperatures near 32 F, but temperatures had plummeted into the mid-teens by the end of the morning rush Thursday.

The combination of the storm over the Midwest and Arctic air lunging southeastward helped to produce blizzard conditions over the northern Plains on Wednesday, closing portions of highways, including Interstate 29, across the region.

“Do not travel” advisories were issued by the North Dakota Department of Transportation across eastern portions of the state as the Grand Forks National Weather Service office said that travel conditions were “near impossible” for a time.

Places in North Dakota also experienced some of the most extreme temperature swings on Wednesday. In Grand Forks, temperatures dropped 81 degrees Fahrenheit within eight hours.

Some unique weather phenomena occurred amid the brutal cold, one of which is known as a sun halo. Residents in Grand Forks captured this rare occurrence on Thursday morning. The halos are created through the reflection and dispersion of light from ice particles found in cirrus or cirrostratus clouds cause by freezing weather. Sea smoke, another spectacle triggered by the painful cold, created an eerie start to the coldest morning of the season in Minnesota.

Although blizzard conditions and the most extreme cold are not anticipated for much of the Midwest, the Arctic blast advancing over the region is expected to produce the lowest temperatures of the season so far for many locations.

As snow plowed eastward, 2-6 inches accumulated from Chicago to Indianapolis and Columbus, Ohio. Snowy conditions and plunging temperatures have prompted 300 cancellations and nearly 1,000 delays of arriving and departing flights at Chicago’s O’Hare International Airport as of early afternoon on Thursday, according to FlightAware.

As the leading edge of Arctic air advances across the lower Great Lakes region and part of the Ohio Valley, temperatures will fall several degrees and even plummet 20 degrees or more during the day Thursday.