Summer streamflows in Colorado are expected to peak lower than average after a warm, dry start to the water year
Eagle County had a stronger snowpack and a wetter winter than most of the rest of the state
Zoe Goldstein/Vail Daily
The 2025 water year has been warm and dry so far. The summer outlook forecasts more hot weather, below average streamflows, and the possibility of some precipitation.
Russ Schumacher, the Colorado state climatologist based out of Colorado State University in Fort Collins, reviewed the year in water so far at the Eagle River Valley’s State of the River on Thursday at Colorado Mountain College in Edwards.
“Given where the water situation is and the current drought situation, I think there are some pretty serious concerns, especially to the southwest of here,” Schumacher said.
‘Not exactly where you want to be:’ Warm, dry start to 2025 water year
The water year is the 12-month period beginning Oct. 1.
The 2025 water year began with the second warmest October of the last 130 years of temperature measurements in Colorado. Colorado’s 2025 water year start is tied for the 10th driest out of the last 130 years.
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The year has not been as dry as it has been warm — it has only been the 40th driest year out of the last 130 years, which indicates relatively average wetness.
However, when analyzed month by month, there has been a lot of fluctuation. November 2024 was the fifth wettest November out of the last 130 years, while December 2024 was the 12th driest December.
For Eagle County, it was the 19th warmest and 31st driest first seven months of the year since the late 1800s.
“Not up there with some of the really extreme drought years of 1934, 2012 and 2002,” Schumacher said. “But still not exactly where you want to be for this part of the water year.”
For May, Western Colorado has been “really dry thus far,” Schumacher said.
The western half of Eagle County is in the “severe drought” category on the U.S. Drought Monitor as of May 27, while conditions are “not as bad” into eastern Eagle County and Summit County, Schumacher said.
Snowpack in Eagle County is strong compared to the rest of the state
One of the best indicators of each year’s summer water outlook comes from spring snowpack measurements.
Snowpack typically peaks around April 10 at the SNOTEL stations. On April 10 this year, snowpack in Colorado’s northern mountains was close to average, while snowpack in the southern mountains was “pretty bleak,” at 50% to 70% of average, Schumacher said.
The average is taken from a 1991-2020 median.
The Vail Mountain SNOTEL station peaked at the 15th percentile, meaning 85% of years had more snow at peak than 2025.
The Fremont Pass station peaked at the 30th percentile. “That’s still not great,” Schumacher said.
Copper Mountain peaked at the 50th percentile — exactly average — and continues to hold snow as Vail Mountain melts out.
“Summit County into Eagle County was definitely the bright spot this winter in terms of snow, because if you go further southwest into the San Juans, it was very bad. Some places had their first or second lowest snowpacks,” Schumacher said.
Snowpack this winter was “not great in this part of the state, but not among the worst in the state, either,” Schumacher said.
As of May 18, following a dry, warm April and May in the mountains, the situation became more dramatic. “Everything got worse there, and that’s because the melt started happening early,” Schumacher said.
Snowpack in the Colorado headwaters area, which includes Eagle County, was at 58% of average, and even less snow remained in the southern mountains.
“Those southern basins didn’t have a great snowpack to begin with, and they started melting early, so those really dropped off fast. In the northern basins, the peak was not so bad but then the melt happened early, and so not so good there,” Schumacher said.
Low snowpack combined with early melt-off can be a recipe for a low water year. But the melt slowed over the last few weeks due to cooler weather.
While the average melt-out date is typically around mid-June, Schumacher predicted it will come “a little bit early this year, with that pattern.”
Eagle River flows expected to peak earlier, below average this year
Overall, snow is melting earlier than before due to climate change. When median water discharge in the Eagle River is compared between the periods of 1971 to 2000 and 2001 to 2024, the peak flow date moved up from June 11 to June 10. Overall, “everything is shifting earlier,” Schumacher said.
Colorado State University’s report on climate change predicts that runoff timing will be earlier “with high confidence,” now and into the future, Schumacher said.
This year, peak flow in the Eagle River “will be below average,” Schumacher said. “But we’ll see how much below.”
Total streamflow has declined by about 8.5% in a comparison of stream volume averages from 1971 to 2000 and 2001 to 2024. “But where the declines are really sharp is in the summer, summer into early fall,” Schumacher said.
Flows from July through September have declined by about 25% in the modern quarter century compared to the last quarter of the 20th century.
While climate modeling reports are “unsure” about how peak streamflow will change in volume, with some predicting wetter winters and some predicting drier, “every single one of them shows the streamflow shift from a peak in that mid-June period to earlier, and then very reduced flows in the summer and into the fall, because it’s warming, so the snow that falls, it melts out earlier and then you get the water in the rivers earlier,” Schumacher said.
The streamflow forecast anticipates that the Eagle River in the Gypsum area will reach 85% of average for April through July. “So below average but not terrible,” Schumacher said.
The further water travels from the headwaters, the worse the outlook gets: Lake Powell is predicted to be at 55% of average for the same period.
The weather outlook for June through August shows high confidence of a hot summer across the western United States.
“That has been the trend in summers and looks like it will continue this year,” Schumacher said.
“Precipitation is more mixed,” Schumacher said.
While the northwestern U.S. will be dry this summer, a monsoon may move in from the southwest.
“It’s not going to fix the water situation, but hopefully that is good news for keeping wildfire risk down,” Schumacher said.
