Winter Storm Valerie Dumps 40+ Inches of Snow in Colorado; Cheyenne, Wyoming's Heaviest Late-Spring Storm in 74 Years

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The top amount from Valerie so far was 42 inches near Allenspark, Colorado, followed closely by 41.7 inches of mid-May snow near Ward.

Estes Park, Colorado, reported anywhere from 25 to 36 inches of accumulation.

Snow amounts in the Denver metro area ranged from just a trace officially at Denver International Airport to roughly 1 to 3 slushy inches in Thornton, Aurora and Ken Caryl inside 470, to nearly 5 inches with some minor tree damage in Arvada and Broomfield. 

Several thousand Xcel Energy customers in Boulder and Jefferson County, Colorado, had lost power as of late on the 18th.

The snow forced at least a partial closure of much of the 350-mile stretch of Interstate 80 in southern Wyoming from west of Cheyenne to Evanston, according to the Wyoming DOT. 

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Here are a few selected snowfall totals from Valerie.

• Colorado: 42 inches near Allenspark; 26.2 inches at Breckenridge; 7.5 inches south of Ft. Collins with tree limbs damaged
• Idaho: 11.0 inches near Pierce; 9.0 inches near the Red River Hot Springs
• Montana: 31 inches near Nye; 6 inches in Bozeman; 4.5 inches in east Missoula
• Nebraska: 2.0 inches near Harrison
• South Dakota: 4.4 inches near Lead; 0.6 inches in downtown Rapid City
• Utah: 7.2 inches at Alta; 5.0 inches near Smithfield; 0.3 inches in downtown Salt Lake City
• Wyoming: 32.2 inches estimated about 21 miles west of Cheyenne; 20.0 inches near Lander; 17.0 inches at Teton Pass (8,200 feet); 8 inches in Laramie; 14.0 inches south of Casper

How Unusual Was This So Late in Spring?

May, even June snowfall in the highest elevations of the Rockies is not unusual.

However, for some lower elevation cities on the High Plains, this was quite an event this late in the season.

Cheyenne, Wyoming, picked up 11 inches of snow on May 18th alone. 

While Wyoming's capital city has picked up several less-heavy snow events as late as mid-June, this was the heaviest calendar-day snow so late in the spring on record, there.

In fact, the only other snowstorm of record with at least 11 inches of snow this late in spring occurred 74 years ago, during World War II.

Accumulating snowfall beyond the middle of May in the Mile-High City, is rare, but not unprecedented.

The National Weather Service issued a winter storm warning for the city of Denver during Valerie, only the 4th time a winter alert had been issued for Denver in May since 2006.

Denver has seen accumulating snow as late as June 5 (1953) and a trace of snow as late as June 12 (1947).

Salt Lake City recorded their first measurable May snowfall in seven years, despite being only 0.1 inch. 

Logan, Utah, picked up more than 4 inches of snow by May 17, only the second time in history dating to 1893 they've had such a heavy snowfall so late in the spring.

The weight of wet snow triggered power outages and downed trees in the city of Missoula on May 17. Missoula received 2.7 inches of snow.

Portions of I-90 in the Homestake Pass east of Butte, Montana were blocked for a few hours in both directions during the afternoon of May 17 due to jackknifed semis. Conditions were reportedly snowy and icy at the time of the crashes. 

An estimated 9 inches of snow in Bear Canyon near Bozeman, Montana, snapped numerous tree limbs and triggered power outages late on the night of May 17, according to the National Weather Service.

Jonathan Erdman is a senior meteorologist at weather.com and has been an incurable weather geek since a tornado narrowly missed his childhood home in Wisconsin at age 7. Follow him on Facebook and Twitter.

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