Snowpack/runoff news: Dust on snow lacking this year due to spring weather patterns

Westwide SNOTEL snow water equivalent as a percent of normal April 8, 2015 via the NRCS
Westwide SNOTEL snow water equivalent as a percent of normal April 8, 2015 via the NRCS

From The Grand Junction Daily Sentinel (Dave Buchanan):

A quick look around the Elk Mountains last Friday from the top of Snowmass Ski Resort revealed something not seen in nearly a decade: Mountain peaks coated in white snow.

That might not seem worth reporting, except for its rarity. This, according to the Center for Snow and Avalanche Studies, is the first spring in the past 10 when dust, blown in from elsewhere on the Colorado Plateau, hasn’t discolored the snowfields covering Colorado’s high country…

In recent years, though, spring dust-laden storms similar to the one that hit the Grand Valley on Friday have carried what the Center for Snow and Avalanche Studies is calling an “increasing amount” of cinnamon-colored dust onto Colorado’s alpine peaks, creating dark, dirty-looking snow that absorbs more sunlight and melts more quickly…

This year’s lack of dust-covered snow wasn’t because of a shortage of dust, said Landry, but rather the lack of the right weather patterns.

“Earlier in March the dust wasn’t available (for transport because) the Greater Colorado Plateau received snow and rain during that time,” he said. “A couple of large storm systems cut the availability of dust” even though those storms were windy enough to bring dust to the mountains.

“And then the weather missed the plateau for the rest of March,” Landry said.

He said Friday’s storm was a non-event in regard to high-altitude dust deposition since most of the disturbance was at low elevations.

Landry’s studies, in conjunction with those from the U.S. Geological Survey, say the vast majority of the dust covering the mountains comes from the Greater Colorado Plateau.

“We don’t even talk about other sources,” said Landry, discounting theories blaming deserts in China as a major source of Colorado’s wind-blown dust.

“Such a strong relationship has been established” through analysis of the dust chemistry with parts of the Greater Colorado Plateau, Landry said.

“There are any number of locales within the plateau that can be contributing a lot of (dust) depending on the particulate size, wind, soil conditions and things like that.”

He also said local sources of dust can be major factors.

“The parking lot at A-Basin (ski resort) is pretty intense,” he said with a laugh.

The drought is one reason there is more dust being carried by the wind, but what produces the dust in the first place?

Landry said “anthropogenic causes” such as motor vehicles, livestock grazing, fires and private and commercial development are “clearly recognized to make dust available.”

“But then the drought can also be a factor in that disturbed soils have more difficult time recovering and vegetation may not recover at all,” he said.

And simply receiving more rain might not be the answer.

“In a real ironic twist, in the fall of 2013, there were major rains in the mountains and on the plateau and then there was the corresponding flash flooding,” Landry recalled. “All that streamflow mobilized a whole bunch of new silt, which subsequently dried up and became a new crop of dust available for the next spring.”

“So massively wetting the Colorado Plateau actually made it worse, we speculate,” he said.

April can be one of western Colorado’s windiest and snowiest months and Landry expects to see more dust-on-snow events.

“The only way we’ll get more snow pack is to get some very large spring weather systems, which are increasingly likely to mobilize dust,” he said laughing. “So, it’s a Catch-22.

“But I think everyone would prefer having the water.”

More information about dust-on-snow and the Center for Snow and Avalanche Studies is available at http://www.snowstudies.org.

From the Summit Daily News (Ali Langely):

Snowpack in Summit County’s Blue River Basin hovered slightly above average for the last few months and, after several stretches of close to record-breaking warm weather, dropped to average in late March and below average in early April.

The USDA’s Natural Resources Conservation Service SNOTEL sites recorded local snowpack on Wednesday, April 8, at 92 percent of the seasonal average for the date. Summit’s snowpack also measured 89 percent of the average seasonal total.

Snowsports enthusiasts, water supply managers and those in the recreation industry in Summit consider this spring’s snowpack to be better than those in 2012 and 2013, when they were recorded on April 8 at about 45 percent and 73 percent of average, respectively, but not as good as 2011 and 2014, which both saw close to 140 percent.

“It’s hard to compare,” Wade said. In 2014, “we had such a banner year.”

In his 23 years in the county, Wade said he has never experienced such a long paddling season on the Blue River as he did last year.

Wade said even if the weather patterns continue, he remains optimistic about the 2015 season. Paddlers are already enjoying flows on the Upper Colorado River, he said, and stand-up paddleboarding on Dillon Reservoir is growing in popularity.

“If nothing happens, we still will have water, we still will have river flow, there will still be business,” he said.

THE COLORADO PICTURE

Statewide, a short-lived weather pattern in late February and early March resulted in snowpack gains, but the falling snow lasted only until March 6. Then the sky’s faucet shut off through the rest of March.

From March 6 through April 1, the state recorded the second-driest stretch for that time period dating to 1986; only 2012 was drier.

To compound the issue, warm early spring temperatures melted the snowpack, especially at lower and some mid-mountain elevations.

Seasonal snowpack decline this early in the spring is rare and occurs in one of every 10 years, according to a report produced by the Natural Resources Conservation Service (NRCS).

2012 was the extreme case in which snowpack melting began early and continued unabated through the spring due to above-normal temperatures.

“While late-season snowstorms large enough to provide the kind of moisture we need in the mountains of Colorado are possible, they are not probable at this point,” said Brian Domonkos, hydrologist with the NRCS Colorado Snow Survey Program. “Coloradans and other downstream water users should be prepared for below-average streamflows this spring and summer.”

Statewide snowpack recorded on Wednesday, April 8, was 65 percent of normal, down from 87 percent last month, according to SNOTEL and snow course observation sites. That means this year’s snowpack ranks third from the minimum year of 2002 in a 30-year period of record.

The persistent bright spot in the state, the report said, is the South Platte River Basin where snowpack was 110 percent of normal last month. Though the South Platte experienced a large decline in March, it recorded the most snowpack of the state’s river basins on April 8 at 85 percent of normal.

“That means they won’t take as much down in Denver” from Summit, Wade said, referring to water pulled through the Roberts Tunnel in Dillon Reservoir by Denver Water to supply Front Range residents.

The Colorado River Basin, which includes Summit County, recorded an overall snowpack of 70 percent of average.

Colorado mountain snowpack typically peaks on April 9, but the NRCS report projected this year’s peak will have occurred one month earlier, closer to March 9, if warm temperatures and below-normal precipitation continue.

Snowpack deficits will negatively impact reservoir storage, which remains better in the northern half of Colorado while the southern half has stayed below normal.

“March is the second most significant month for mountain precipitation in Colorado. April is the most important, so if this dry trend continues through April, it would be a real one-two punch to Colorado’s water supply,” Domonkos said.

AT LOCAL SKI RESORTS

Summit’s ski resort officials have said early-season snow helped conditions through much of the spring despite much lower than average total snowfall.

Arapahoe Basin Ski Area reported that 100 percent of its easy, intermediate and difficult skiable acres were open Wednesday, while 84 percent of its expert terrain was open.

At Breckenridge Ski Resort, 99 percent of the terrain was open. Copper Mountain Resort was 67 percent open, and Keystone Resort, which closes Sunday, was 48 percent open.

Nearby, Loveland Ski Area was 91 percent open, Vail Mountain was 79 percent open and Beaver Creek, which also closes Sunday, was 43 percent open.

According to snowfall data reported by Breckenridge Ski Resort and compiled by OnTheSnow.com, the ski area was blessed with heavy snow for a few days in a row in mid-November and again right before the Thanksgiving holiday.

In December, Breckenridge reported 29 inches in two days just before Christmas and more snow before New Year’s.

The rest of the season has been slow for powder hounds.

January’s snowiest day at Breckenridge was the 20th, with 7 inches, and the ski area reported five days of 4 inches or more that month.

As is typical, February was snowier than January, but this year it wasn’t by much. February’s snowiest days at Breckenridge were Feb. 5 and 21, when the ski area reported 9 inches. That month saw seven days of 4 inches or more reported.

Then in March, the ski area reported its snowiest day on the 4th, with a meager 6 inches, and the month saw five days of 4 inches or more.

So far in April, local ski areas have recorded one powder day, on Friday, April 3, and none will extend its season. Last year every local ski area pushed back its closing dates.

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