Colorado’s snow season is nearing its typical peak with above-average snowpack, and water officials are beginning to worry about flooding and gauging potential reservoir releases. But in some places, the snow just keeps coming.
Each year, April marks the point in the season when the snowpack starts to reach its peak as temperatures warm and spring runoff begins. It’s also an important point for water officials, water users and even emergency managers: How high the snow piles up is a key indicator of water supply for the next year, but how fast it melts can have big impacts on flooding and seasonal irrigation.
“We do anticipate high water,” said Sgt. Todd Wheeler, emergency management coordinator for Moffat County in northwestern Colorado. “Will it be higher than normal? That remains to be seen.”
In the Colorado River Basin, which supplies water to 40 million people spread across seven Western states and 30 Native American tribes, the snowpack was above average as it reached its seasonal peak.
In the Upper Colorado Region, which includes Colorado, New Mexico, Wyoming and Utah, the snowpack usually peaks around April 8, and on Thursday, it was about 160% of the median from 1991 to 2020, according to Natural Resources Conservation Service data. It was even nearing the highest snowpack recorded since 1986.
The Lower Colorado Region, which includes Arizona, California and Nevada, was at 446% of the historical median as of Thursday.
The above-average snow is welcome news for the parched basin, which is facing its worst drought in 1,200 years. However the basin’s two largest reservoirs, Lake Mead and Lake Powell, will need to see this kind of snowfall for multiple years to recover from the impacts of prolonged drought and overuse, experts say. The water levels at Lake Mead are even projected to fall further this year, according to the Bureau of Reclamation.
“While this year has been really good news in terms of above-average snowpack and above-average stream flows into Lake Powell over the summer, it’s not enough to totally refill those reservoirs or even get them back to normal,” said Peter Goble, a climatologist with the Colorado Climate Center at Colorado State University.
The seasonal peak refers to the snow-water equivalent — the amount of liquid water in snow — in the snowpack. The peaks vary regionally and year to year, and the data can be sparse for elevations higher than 11,000 feet and lower than 9,000 because of the distribution of data collection stations, called SNOTEL sites, Goble said.
In Colorado, the snowpack has already passed its historical peak in southern basins, including the Upper Rio Grande, Arkansas and the combined San Miguel-Dolores-Animas-San Juan basin. Northern basins, like the Yampa-White, Gunnison, Colorado main stem, North Platte and South Platte, will peak this weekend or later this month.
That means more winter storms might roll through — and help add to the water supply — but they will balance out with spring runoff as temperatures warm.
“That’s not to say that the moisture that falls after peak snowpack isn’t important,” Goble said. “In fact, it is really important, what happens in late April and May, in terms of the overall runoff that we get. But I think you’ll probably see our numbers peak quite soon here.”
Western Slope river basins, which feed the Colorado River, were all reporting above-average snowpack Wednesday. The snowpack in the Upper Rio Grande basin, which usually peaks April 2, was at 135% of the historical median, according to SNOTEL data Wednesday.
In southwestern Colorado, the combined San Miguel-Dolores-Animas-San Juan basin blasted past its historical median this season, reporting the highest snowpack in the state at about 180%. The basin typically peaks April 2 with a snow-water equivalent of 18.1 inches. This year, the basin reported 31.5 inches, which is half an inch lower than the maximum recorded between 1987 and 2022.
“In the modern SNOTEL observation era, we’re right on the doorstep of a record,” Goble said. “I’m not sure if we’re going to get there … but we’re going to get darn close to a new, modern era snowpack record in the San Juan combined basin.”
The region has been hit hard by the drought in recent years, and water officials, farmers, ranchers and other water users are enthusiastic about the deep snowpack.
For Ken Curtis, general manager of the Dolores Water Conservancy District, the plentiful snowpack means that the local reservoir will fill, and the district is even starting to plan a managed release for rafters and ecological purposes, he said.
Montezuma County emergency manager Jim Spratlen said the high snowpack could also mean flooding as rivers swell in May and June. Spratlen’s team was already updating emergency planning resources online and handing out sandbags to people in the towns of Dolores and Mancos in early April as a precautionary measure.
“Basically, we prepare for everything,” he said. “We prepare for the worst and hope for the best.”
As of Thursday, projections from the Colorado Basin River Forecast Center indicated that three areas of the Western Slope, in Moffatt, Routt and Gunnison counties, are already more than 50% likely to see flooding.
Higher, northern elevations are still seeing new snow, and spring runoff is weeks away; however, emergency managers in those areas are also preparing for the spring runoff.
They’re taking precautionary steps, like clearing ditches and culverts, holding planning meetings, running high-water public service announcements and monitoring flow-rates and areas prone to flooding. They’re also watching weather forecasts for signs of prolonged warming, higher nighttime temperatures and dust-on-snow events, all of which can speed melting.
☀️ READ MORE
The Gunnison County snowpack was well above average according to SNOTEL data, said Scott Morrill, the county’s emergency manager.
“What the Snotel data does not reflect is the mid and low elevation snow levels/water content,” he said in an email to The Colorado Sun. “As of a couple weeks ago, readings at all of the low/mid elevation sites were very high, with some of them at historic highs.”
The Gunnison and Yampa-White basins were at 161% and 146% of their historical medians, respectively, as of Wednesday. Both will pass their usual seasonal peaks this weekend. The Colorado main stem, which was 132% of its historical median Wednesday, usually peaks around April 14.
In Routt County, particularly north of Steamboat Springs, conditions are similar to 2011 which was a big flood year, said David DeMorat, emergency operations director.
“It all depends on how quickly it melts. That’ll be a key thing,” he said.
Before the spring runoff heightens in coming weeks, the key for community members is to contact their local emergency management offices and sign up for their alert systems, Spratlen said.
“To us, that is one of the biggest things that the public really needs to do, and then they will be notified if something’s going on,” he said. “They’re going to be very aware of it, whether it’s a law enforcement issue, a flood, a fire evacuation, or whatever.”