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Snowpack report: ‘Big’ winter not so big after all

The National Resources Conservation Service released its latest statewide snowpack report last week, and what seemed a particularly hard winter to many has actually been subpar for most.

As of April 1, the Arkansas and Rio Grande river basins showed well-above-average snowpacks, with totals of 109 and 115 percent, respectively. While the combined San Juan, Animas and Dolores basins were 101 percent of average, five major river basins to the north reported totals well below average. The combined Yampa and White basins showed the least, with a snowpack just 73 percent of average. Statewide, the early April snowpack was a gaunt 88 percent of average.

“Colorado continues to feel the brunt of a deeply entrenched El Niño weather pattern as the 2010 snowpack nears its normal seasonal maximum,” Mike Gillespie of the NRCS stated in his April 5 report. “The latest snow survey, conducted by the USDA-Natural Resources Conservation Service, indicates little to no significant improvement in snowpack percentages during the month of March.”

NRCS State Conservationist Allen Green added that Colorado’s snowpack percentages remained unchanged from March 1 to April 1, though this year’s snowpack has improved monthly, compared to that of last year. By the first of April, this year’s total stood at 92 percent of April 2009 — an improvement of 10 percent since the March 1 comparison a month earlier.

Gillespie explained that the continuation of this winter’s El Niño pattern has resulted in below-average snowfall and precipitation throughout the northern river basins, while storm tracks have graced the southern basins with near, or slightly above-average, moisture.

In his report, Gillespie added, “In a typical year, mountain snowpack totals reach their seasonal maximum totals during the month of April. This leaves only a few weeks remaining where improvements can be made. Given the current deficit across northern Colorado,” he continued, “the odds of reaching a near average snowpack remain at less than 10 percent at this time.”

As one would expect, with much of Colorado under a marginal snowpack, Gillespie believes the outlook for spring and summer water supplies will also fall short of normal expectations. That, because only portions of the southern basins will see near average runoff, while runoff in the northern basins will be below — to well below — average. Again, only the Arkansas and Rio Grande basins should see average or better runoff this season.

If Gillespie’s report contains a silver lining, it’s that reservoir storage remains at or near average across most of the state. Statewide, it stands at 106 percent of average, while northern basins with the lowest snowpack actually claim the highest percentages of average storage.

The Rio Grande basin is one of just two Colorado basins containing below-average storage. With storage at 90 percent of average, though, it also holds the state’s highest percentage of average snowpack at 115 percent.

If any basin in the state has cause for concern regarding late summer water supplies, it’s the combined San Juan, Animas and Dolores basins. With an almost average snowpack (101 percent) by April 1, its water storage was just 87 percent of normal for the date. Compared to April 2009, this year’s combined basin storage is just 81 percent of last year’s total.

As Gillespie said, it’s unlikely that Colorado will achieve an average snowpack by the end of April. To get there, in fact, El Niño would have to end immediately, thus allowing significant storms to track further north, while still bringing meaningful precipitation across southern regions.

Current weather models don’t seem favorable. Here in Pagosa Springs, for instance, we’ve seen 0.28 inches of precipitation so far this month, mostly in the form of two inches of snow. While we normally receive 1.36 inches of April moisture — including five-and-a-half inches of snow — recent storms have not materialized as predicted, and the forecast suggests a drying and warming trend, with brief unsettled disturbances amounting to minimal rain or snow.

With that in mind, however, today and over the weekend should bring sunny to partly cloudy skies, with daytime temperatures ranging in the 70s. While that kind of weather won’t likely ease concerns over late-season water supplies, it may go a long way in quelling community-wide complaints of constant gray skies and seemingly endless winter.

We’ll see.

chuck@pagosasun.com