Many of the major river basins are at or above average, but surveyors are worried that drought conditions won’t improve
Snowstorms last month replenished snowpack in the Colorado mountains and improved drought conditions on the Front Range, as did rain that quenched the parched Eastern Plains. But smaller amounts of precipitation farther south and west have done less to dampen drought conditions.
Ultimately, researchers say that one big storm is not enough to break Colorado out of its long-term drought.
“What we’ll need are probably multiple years of above average snowfall to really get us out of this,” said Russ Schumacher, Director of the Colorado Climate Center.
Snowpack, the snow that accumulates in the mountains, provides Colorado with 50% to 80% of its usable water. As temperatures rise in April and through the spring, melting snow renews the rivers and fills reservoirs throughout the state. Last month’s snowstorm was a boon.
Data from the Natural Resources Conservation Service of Colorado shows some promising snowpack conditions. The snow-water-equivalent — the amount of liquid water held in snow — is at or above 90% of normal in the Yampa, White, Laramie and North Platte and South Platte river basins. In the Arkansas and Upper Rio Grande basins, it is 110% of normal. Conditions are not as good in the Upper Colorado Headwaters, Gunnison, and San Miguel, Dolores, Animas and San Juan basins, all under 90% of normal.
“We’re definitely in a better position now at the beginning of April than we were at the beginning of March,” said Russ Schumacher, director of the Colorado Climate Center at Colorado State University.
Brian Domonkos, snow survey supervisor at the Natural Resources Conservation Service of Colorado, measures snowpack to gather data on the important snow-to-water equivalent. In the past couple weeks, the statewide snow-water-equivalent jumped up to almost 15 inches, just under the median.
Two methods are used to determine the amount of water present in the snowpack. The more traditional way uses a federal sampler — a set of tubes stuck into the snow to produce a core that is measured and weighed. Snow telemetry, or SNOTEL, sites are an automated method for measuring the water in the snow, while also collecting data including depth, quality of snow, precipitation and air temperature.
However, heavy snowfall does not always mean snowpack will provide enough water for the state or reliant neighboring states. There are a number of other elements at play.
Warm, windy conditions can erode snowpack fairly quickly. In some instances, dust can blow in from the Southwest, blanket the snow and reduce its reflective abilities. If covered with dust, the snow absorbs more sunlight, making it melt faster than usual.
Soil moisture is crucial, but it is a factor Schumacher said researchers are still working to fully understand. Going into the winter with dry soils means it takes more water to rehydrate them first before water can flow into rivers. A warmer spring means snow might melt faster than expected.
“The dry conditions that we’ve seen over this past summer, and even the summer before that are one of the bigger drivers of the below-normal stream flows,” Domonkos said.
Climate change exacerbates this moisture challenge. Schumacher said it can bring about extreme heat and a rapid onset of drought in the summertime, reducing soil moisture.
“If that trend continues, and we continue going into each winter with very dry soils and drought-stressed vegetation, then it just raises the bar on the amount of extra snow that you have to get to make up those deficits,” Schumacher said.
Signs point to more drought conditions, but Domonkos said time will tell.
“For me I think the real proof is going to be in the actual runoff this spring and summer,” Domonkos said. “Unfortunately, that’s just the way that it goes.”