#Snowpack/#Runoff news: Melt-out continues, unsettled weather statewide this week

From Grand Junction Daily Sentinel (Dennis Webb):

March and April failed to deliver their usual snowpack punch this year in Colorado, but most river basins have above-normal peak snowpack levels thanks to storms in earlier months.

The Natural Resources Conservation Service said in a news release last week that March and April, “typically the two wettest and most pivotal months of the year in the mountains of Colorado” for snowpack, produced 76 percent of their typical precipitation this year.

But snowfall that was nearly twice the average amount in December and January assured generally decent peak snowpack levels before melting began this year, with southern Colorado amounts ranging from 120 percent to 130 percent of usual peak, the service said.

It said that only the North Platte River Basin peaked below the normal amount, while the Upper Rio Grande Basin and combined San Miguel, Dolores, Animas and San Juan river basins reached their greatest peaks since 2008.

Poor snowfall combined with melting in March and April contributed to the state’s snowpack level falling to below average, at 95 percent of normal, as of the start of this month. That’s down from 108 percent as of April 1, 139 percent on March 1 and 156 percent on Feb. 1.

By Thursday, however, the state number had rebounded to 104 percent thanks to storms that rolled in last week.

As of Friday, the Upper Colorado River Basin snowpack stood at 103 percent of normal, and the Gunnison River Basin was at 114 percent, the highest of any basin in the state. The combined Yampa and White River basins had the lowest amount, at 90 percent of normal.

“In general, snowpack contribution to water supply should be near normal across the state,” the conservation service said.

It said the Yampa/White basins and parts of the South Platte Basin have potential for below-normal streamflows, but elsewhere streamflow forecasts are largely near normal, with the exception of the Gunnison, where a number of locations are predicted to flow at nearly 140 percent of average.

Reservoir storage continues to remain strong in Colorado, at 112 percent of average as of the start of the month. Overall storage in the Gunnison basin is 126 percent of average, while storage in the Colorado River basin is 113 percent of average.

The Natural Resources Conservation Service said storage levels in Colorado this year and last year have been some of the highest in more than a decade, and reservoirs are in a good position to provide water this summer.

Westwide SNOTEL basin-filled map May 7, 2017 via the NRCS.

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