Snow in the San Juans: La Niña Turns Fickle
by Peter Shelton
Jan 04, 2012 | 1720 views | 0 0 comments | 10 10 recommendations | email to a friend | print
<b>TOO MANY COVER INTRUSIONS</b> – The Ouray Town Hill rope tow opened “by the skin of our teeth” with a significant snowfall before Christmas, according to lift manager Dylan Baer. But now the city has decided to close the free, after-school hill until the next storm replenishes the thin cover. Ski areas around the state are dealing with the effects of a fickle La Niña weather pattern, resulting in base depths around 60 percent of average for this time of year. (Photo by Brett Schreckengost)
TOO MANY COVER INTRUSIONS – The Ouray Town Hill rope tow opened “by the skin of our teeth” with a significant snowfall before Christmas, according to lift manager Dylan Baer. But now the city has decided to close the free, after-school hill until the next storm replenishes the thin cover. Ski areas around the state are dealing with the effects of a fickle La Niña weather pattern, resulting in base depths around 60 percent of average for this time of year. (Photo by Brett Schreckengost)
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Ski resorts in the eastern U.S. got a nice surprise storm over New Year’s weekend. Colder temperatures and 5-8 inches of snow from West Virginia up to Vermont helped remind New Englanders what winter is supposed to be like. Prior to the storm, flowers were popping up, and temps were too warm in many places to make snow.

Colorado is not the only part of ski country that is hurting right now. California’s usually snowy Sierra is limping along with snow totals in the teens. The Midwest is white in places, but not much to write home about. Vail is reporting 18 inches. Winter Park and Steamboat are in the low 20s. Telluride and Purgatory, with 30-inch bases, look on paper to be among the favored. But the snow cover is thin and getting thinner, and the National Weather Service forecast for the period immediately ahead isn’t promising.

NWS is predicting sunny days for western Colorado with highs in the 40s and 50s through the end of the weekend. “We may see a quick shortwave energy pass through the dominant ridge of high pressure, mostly north and with little to no precipitation. The ridge rebuilds Monday heralding more dry sunny conditions with mild temps.” Only Washington State in the far northwest has benefited, so far, from the La Niña regime controlling our weather.

La Niña is a fickle child. Last year’s ENSO (El Niño Southern Oscillation) – in which scientists also measured cooler than average water temps in the eastern equatorial Pacific (La Niña is cool; El Niño is warm) – resulted in an average snowpack for the San Juans bookended by wetter than normal early and late seasons.

This year, she’s not following the same pattern. “What I’m seeing,” said long-time weather observer and avalanche forecaster Jerry Roberts, “is unusual for a La Niña. La Niña storms usually favor the northern mountains. This year the storm track is splitting and going north and south of us.” Way north and way south.

In a typical La Niña, one would expect to see slightly cooler temps and a little less snow across the southern tier of the U.S. This year we’re seeing warmer than average temps and below average snowfall. Snowpack numbers this week are dipping to near 60 percent of the 30-year average statewide.

National Weather Service meteorologist Joe Ramey, from Grand Junction, answered a query on Tuesday with this somewhat downbeat interpretation: “I wasn't too worried through December, with the big ridge off the west coast the storms were diving due south through the inter-mountain west producing only light snow here in western Colorado. By Christmas we could see that pattern breaking down to a . . . more progressive pattern with the storms tracking across the northern tier of states, which is typical of La Niña. Also, January has a strong snowy climate signal under La Niña conditions. This held out hope for increased snowfall, at least favoring the northern mountains. But that pattern devolved into this moderately amplified pattern with the ridge in the eastern Pacific again blocking us from the storm path. Now I am getting worried, with this pattern prognosticated to persist for the next 10 days at least.

“Current Snotel sites are running roughly 60-70 percent of average for this date. (Upper Rio Grande and Arkansas [river basins] are higher from the upslope events in December.) And of course these percentages will be dropping significantly over the next week or more.

“The official 6-10 and 8-14 day forecasts reflect this pattern with increased probabilities of below-normal precipitation.

“The longer Jan-Feb-Mar seasonal outlook still holds on to the La Niña pattern of increased snowfall across the north.

“Crossing all my appendages with hopes for a pattern change!”

In Ridgway, Roberts still holds out hope: “We get one of those big San Juans storms, and we’re back up to 80 percent.” But, he said, “snow-depth totals always seem to drop quickly and rise slowly.

“It’s just one of those years,” he said.

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