Blizzard warnings remain in effect from northeast Colorado and northwest Kansas all the way to South Dakota. Ice storm warnings also blanket eastern North Dakota, where warmer mid-level temperatures are allowing liquid rain to fall before it freezes into a slick sheet of ice.
“Travel could be very difficult,” the National Weather Service warned. “Widespread blowing snow could significantly reduce visibility. Gusty winds could bring down tree branches.”
Even after the snow ends, continued strong winds could loft freshly fallen powder and lead to ground blizzard conditions, which are just as dangerous.
Interstate 90 in South Dakota remained closed between Mitchell (exit 332) to Wall (exit 110) because of hazardous road conditions and limited visibilities, while Interstate 94 in North Dakota featured slow-going travel between Hebron and west of Fargo.
Conditions will remain dangerous through early Wednesday in some spots before improvement finally ensues.
The instigating storm system began its wintry wallop over the Four Corners region, delivering snow to the high terrain of New Mexico and Arizona before reorganizing in the lee of the Rockies. Moisture wrapping around the counterclockwise-spinning low fell into a zone of cold air in the low’s wake. That lead to hefty accumulations in the mountains of Colorado. Then the storm system ejected northeast.
Here’s a roundup of some of the biggest totals thus far:
- 14 inches in Mogollan, N.M.
- 13 inches in Douglas Pass, Colo.
- 13 inches in Sunrise Park, Ariz.
- 12.8 inches in Glendevey, Colo.
- 11.4 inches in Lander, Wyo.
- 10.5 inches in Aspen Springs, Colo.
- 10 inches in Wolf Creek Pass, Colo.
- 8.8 inches in Lawson, Colo.
- 8.5 inches Burwell, Neb.
- 8 inches in McLean, Neb.
- 7 inches in Norfolk, Neb.
- 6.5 inches in Fort Pierre, S.D.
- 6 inches in Tyndall, S.D.
- 4.1 inches in Gann Valley, S.D.
Overall, it should be apparent that the snowfall accumulations over the Plains are far from blockbuster totals — and pretty typical for this time of year. So why the significant impact? Winds are raking the northern Plains and Front Range, kicking up whatever has fallen. Sterling, Colo., along Interstate 76, gusted to 61 mph, while the Denver International Airport recorded a gust to 64. Sidney, Neb., also gusted to 60 mph, and gusts of 45 to 55 mph were common across the northern Plains. Rapid City, S.D., even gusted to 73 mph, just 1 mph below the threshold for hurricane force.
The parent low pressure system was centered in central Nebraska, and, after a period of reorganization, was slowly meandering southeast. That means precipitation will ease in intensity; the low should reach Kansas City, Mo., by evening, and shift toward Paducah, Ky., by Wednesday afternoon.
The worst of the winds should slacken too, with gusts of 40 mph or greater relegated mainly to the High Plains from the Nebraska Sandhills and eastern Colorado to the Texas and Oklahoma panhandles by Tuesday night. Only a few sporadic gusts of 35 mph or greater are expected in the Nebraska Sandhills on Wednesday. That’s why blizzard warnings will be allowed to expire.
In eastern North Dakota, a filament of moisture-rich mild air drawn north on the eastern side of the low has posed problems. That’s because it’s been “overrunning,” or sliding up and over a shallow lip of cold, dense and subfreezing air that’s hugging the ground. That means the moisture falls through the mild air as rain, but then freezes on contact with the ground, transforming the landscape into a virtual ice rink.
By Christmas evening, places such as Rustad and Wahpeton in North Dakota, and Moorhead and Muskoda in Minnesota all had a quarter-inch of ice accretion. Meanwhile Fargo, N.D., had built up 0.4 inches. A half-inch of ice is enough to pull down power lines and cause outages, but so far, relatively few outages were reported.
The Aberdeen Regional Airport in South Dakota had built up 0.25 inches of ice accretion as of Tuesday morning.
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