Blizzard warnings are in effect from northeastern Colorado and northwestern Kansas to South Dakota. Ice storm warnings cover eastern North Dakota, where warm neutral temperatures allow liquid rain to fall before freezing into thin sheets of ice.
“Travel may be very difficult,” the National Weather Service warned. “Widespread snow can significantly reduce visibility. Strong winds can bring down tree branches.”
Even after the snow ends, continued strong winds can lift freshly fallen powder and lead to blizzard conditions on the ground, which can be dangerous.
Interstate 90 in South Dakota was closed from Mitchell (Exit 332) to Wall (Exit 110) due to hazardous road conditions and low visibility, while Interstate 94 in North Dakota had slow travel between Hebron and west of Fargo.
Conditions will be dangerous in some places early Wednesday before improvement finally occurs.
The triggering storm system began its winter wall over the Four Corners region, delivering snow to the high terrain of New Mexico and Arizona before reorganizing in the lee of the Rockies. The moisture surrounding the counter-rotating low fell into the zone of cold air at low speeds. This leads to high concentrations in the Colorado mountains. The storm system then moved northeast.
Here's a roundup of some of the biggest totals so far:
- 14 inches in Mogolan, N.M
- 13 inches at Douglas Pass, Colo.
- 13 inches in Sunrise Park, Ariz.
- 12.8 inches in Glendavy, Colo.
- 11.4 inches on the Vaio, Lander.
- 10.5 inches in Aspen Springs, Colo.
- 10 inches at Wolf Creek Pass, Colo.
- 8.8 inches in Lawson, Colo.
- 8.5 inches Burwell, Neb.
- 8 inches McLean, Neb.
- 7 inches in Norfolk, Neb.
- 6.5 inches in Fort Bear, SD
- 6 inches in Tyndall, SD
- 4.1 inches in Cane Valley, ST
Overall, the snowfall accumulations in the Plains are far from blockbuster totals — and fairly typical for this time of year. So why the significant impact? Winds blow across the northern plains and front ranges, kicking up everything that falls. Sterling, Colo., along Interstate 76, had a gust of 61 mph, while Denver International Airport recorded 64. Sidney, Neb., also had gusts of 60 mph, and gusts of 45 to 55 mph across the northern plains. Rapid City, SD, sustained winds of 73 mph, 1 mile below the hurricane's threshold.
The parent low pressure system was centered over central Nebraska and, after a period of reorganization, slowly meandered southeastward. This means that precipitation will decrease in intensity; The low will reach Kansas City, Mo., by the evening and move toward Paducah, Ky., by Wednesday afternoon.
Winds gusting to 40 mph or higher should decrease, pushing into the high plains from the Nebraska Sandhills and eastern Colorado to the Texas and Oklahoma Panhandles by Tuesday night. Only a few scattered winds of 35 mph or higher are expected in the Nebraska Sand Hills on Wednesday. That's why blizzard warnings are allowed to expire.
In eastern North Dakota, a strand of moist, moderate air pulled north on the east side of the low has caused problems. That's because it “rolls over” or glides over the upper lip of the cold, dense and frosty air that hugs the ground. That means moisture falls as rain through moderate winds, but then freezes on contact with the ground, turning the landscape into a virtual ice ring.
By Christmas Eve, places like Rastadt, Wappeton, Moorhead and Muscota all had a quarter-inch of snow, while Fargo, ND, gained 0.4 inches. Half an inch of snow is enough to pull down power lines and cause outages, but so far, relatively few outages have been reported.
Aberdeen Regional Airport in SD had developed 0.25 inches of snow as of Tuesday morning.
