As the season came to a close, the snowpack for the Yampa/White/Little Snake River basin in the northwest corner of the state and the headwaters of the Colorado River mainstem both peaked around April 9 at 113% and 101% of normal, respectively. The Western Slope’s more southern basins — the Gunnison and San Juan/Dolores/Animas/San Miguel — topped out at 90% and 76% of normal.

And despite a snowy March that boosted precipitation to 117% of normal for the month, the snowpack in the southwest corner of the state peaked not only lower but also earlier than other areas on March 23. The Roaring Fork River Basin, stuck in the middle of the northern and southern mountain ranges, also peaked on March 23 at 91% of normal.

“The storms that we got this year just consistently weren’t driving far enough south to really give the San Juans as good of moisture as the northern Rockies,” said Peter Goble, assistant state climatologist at the Colorado Climate Center. “La Niña may be a factor there because we do see more often the storm track kind of shift northward during a La Niña year.”

This snow pit on McClure Pass shows a mild dust layer in a recent photo. According to the Center for Snow and Avalanche Studies, the first half of spring 2025 hasn’t seen many dust storms, which can cause the snowpack to melt out faster. Center for Snow and Avalanche Studies

SNOWPACK IMPACTS STREAMFLOWS

Most of the water used by the 40 million people dependent on the Colorado River basin comes from the melting annual snowpack, and water managers can use a snapshot of conditions at the end of the winter to help predict how much water will come from spring runoff.

According to the National Resources Conservation Service April 1 Water Supply Outlook Report, the streamflow forecasts for the Western Slope continue to follow the north/south snowpack trend: 95% of normal for the Yampa/White/Little Snake; 96% of normal for the Colorado headwaters; 86% of normal for the Gunnison and 56% of normal for the Upper San Juan.

Some recent data has shown a north/south split in streamflow declines, with rivers in the southern half of the upper Colorado River basin losing a larger percentage of flows in the first two decades of the 21st century than rivers in the northern part of the basin.

The streamflow forecast for the Roaring Fork River is about 82% of average, as measured at the confluence of the Roaring Fork and Colorado River. Ruedi Reservoir on the Fryingpan River is forecast to fill this year, according to U.S. Bureau of Reclamation hydrologist Tim Miller.

Other factors besides the volume of snow can influence how much of the snowpack makes its way into streams as water. In 2021, a near-normal snowpack translated to an abysmal 36% of average runoff into Lake Powell because of extremely dry soils that absorbed snowmelt before it reached rivers. But Karl Wetlaufer, a hydrologist with NRCS, said this year’s conditions don’t mirror 2021 because fall precipitation boosted soil moisture.

“It’s different from several years ago where we went into winter with very dry soils,” Wetlaufer said. “From a runoff efficiency standpoint, I wouldn’t be terribly as concerned as some of those previous years.”

Temperature and storms that drop dust on top of the snowpack can also affect the timing of runoff. Higher than normal temperatures and dry conditions on the Western Slope over the next 10 days could kick off snowmelt in earnest.

“What tends to matter more for the timing of runoff is spring temperatures and certainly right now with the above normal temperatures that we’re seeing, it does look like runoff is probably going to peak earlier this year,” Goble said. “I wouldn’t be surprised if we end up with our peak runoff occurring somewhere between one and three weeks ahead of the time of the year that we see it on average.”

Spring windstorms that drop dust on snow can also contribute to a faster melt. White snow reflects the sun’s rays, but when the snowpack is coated with a darker layer of dust, it absorbs solar radiation, causing earlier and faster-than-normal melt out. According to Jeff Derry, executive director of the Silverton-based Center for Snow and Avalanche Studies, there haven’t been many dust storms yet this year. Two areas that are typically hard-hit by dust — Wolf Creek and Red Mountain passes in the southwestern part of the state — aren’t bad this year.

“There’s a couple of mild dust layers, but overall it’s still pretty light dust,” Derry said. “But that could change with one event on any given day.”

The snowpack conditions and streamflow forecasts in the Upper Colorado River Basin have implications for the nation’s two largest reservoirs, Lake Powell and Lake Mead, which still flirt with record-low levels after more than two decades of drought and climate change. Studies have shown that Colorado River flows have declined nearly 20% from the 20th century average and that about one-third of that can be attributed to higher temperatures driven by climate change. Higher temperatures mean both a thirstier atmosphere and thirstier plants, which can suck up snowmelt before it makes it to rivers.

The snowpack across the entire Upper Colorado River Basin above Lake Powell topped out at 98% of average. And according to the U.S. Bureau of Reclamation’s latest report, spring runoff into Lake Powell is forecast to be just 67% of average. Lake Powell is currently about 32% full, at elevation 3,559 feet.

“It’s looking like another low inflow year into Lake Powell,” Goble said. “It’s this slow-moving combination of getting more than our fair share of drought in recent years, climate change, warmer temperatures, as well as water management issues.”