Sunday Forecast: Western South Dakota in for a Frigid MLK day

BLACK HILLS REGION, S.D. – Many folks have a three day weekend in observance of Martin Luther King Jr. Day! And it will be a good day to stay inside and stay warm. The National Weather Service has issued an Extreme Cold Warning for portions of western South Dakota and northeast Wyoming. Wind chills are expected to be as low as -45° especially in the Northen Hills. Other offices have followed suit with Extreme cold Warnings covering most of the Northern Plains.

This extreme cold is unusual and potentially dangerous, with the National Weather Service forecasting “the coldest wind chill readings of this outbreak”. The Extreme Cold Warning for our region is in effect from 7pm this evening to 11am tomorrow, with a Cold Weather Advisory until 8am Tuesday.

Expect a high around 9°F in Rapid City with an overnight low of -14°F. Wind chills will bottom out around -30°F just after sunrise. The Deadwood area will see similar conditions, with an overnight low around -19°F and wind chills potentially plummeting to -45°F or even lower! Winds will be relatively calm tonight at 5 to 10 mph but will pick up to 10 to 20 mph with gusts up to 35 mph by tomorrow morning. This is why the wind chill will be coldest around sunrise rather than in the midnight hours.

There is still some slight flurries falling over northeastern Wyoming, which could lead to icy and partially snow-covered roads, but things will be clear by this evening. Clear skies at night typically help cool temperatures even further, because the surface of the Earth radiates off infrared radiation into space, which is a loss of energy and causes temperature to fall. With no sunshine to replenish that energy and no cloud cover to keep it from escaping, we’re going to cool off quite a bit.

It’s important to remember that frostbite can occur quickly in extreme cold, and with wind chills, it can happen even faster. According to University of Colorado Health, when the temperature is 5°F and the wind speed is 30 mph, frostbite can develop in just 30 minutes. At -5°F with the same wind speed, it may set in within 10 minutes. With wind chills expected to reach -45°F in some areas, frostbite can occur on exposed skin even sooner. Symptoms of frostbite usually begin with the affected parts feeling cold and painful. If exposure to the cold continues, you may feel pins and needles before the area becomes numb as the tissues freeze. If you think you or someone else may have frostbite, seek immediate medical attention.

We should see some relief on Tuesday with temperatures warming back up to the low 30s under partly to mostly cloudy skies. The next clipper type system will bring low chances for light snow Tuesday night through Wednesday night along with breezy to windy northwest winds.

Rapid City 7 Day

Per grew up in Sioux Falls and graduated from South Dakota Mines. He found his passion for weather reporting by the impact it has on the community, both in how people work and how it brings people together through severe weather preparation. He also has a passion for preventing health issues with Air Quality Index awareness. Per can be found enjoying outdoor activities in the Black Hills when the weather allows.