SNOWMELT

until at least June 2 because of heavy runo on the trail.

“ e amount of water coming down the trail in many spots is really impressive,” Leanne Veldhuis, EagleHoly Cross district ranger, said in a news release. “ ere is currently no good way around the water, so we have closed the trail until the runo lessens or our trail crew can mitigate it.”

CDOT is also working to repair a gaping sinkhole that appeared on Colorado 133 near Paonia. Rushing spring runo overwhelmed a culvert under the highway and caused enough erosion to collapse a section of the road that is roughly 20 to 30 feet wide — and certainly large enough to t a sedan, she said. A temporary bridge should be installed by early- to mid-June, and permanent repairs should begin this fall.

“Lots of monitoring going on, but so far, the only real major failure we’ve had has been on 133,” Constan said. “It’s a good thing that there’s only been one major failure and everything else pulled together OK.” is winter, Colorado saw storm after storm add snow to the growing snowpack in the mountains.

By early April, that buildup peaked. e amount of liquid water in the snow, called the snow-water equivalent, across the Western Slope was 130% to 140% of the median between 1991 and 2020, according to the Colorado Basin River Forecast Center. e estimate is based on SNOTEL data collected using a network of high-elevation instruments that measure snowpack. On the Front Range, the snow-water equivalent lagged below its median this winter.

In the Upper Colorado River Basin, which includes Colorado, New Mexico, Utah and Wyoming, the amount of water peaked in early April at about 150% to 170% of the historical norm. ese states are situated upstream of Lake Powell on the Utah-Arizona border, one of the basin’s largest water storage reservoirs. e reservoir’s dam, Glen Canyon Dam, sends water down to Lower Basin states — Arizona, California and Nevada — which also had an exceptionally wet year, said Cody Moser, senior hydrologist at the forecast center.

However in the Upper Basin above Lake Powell, most of the snowpack is still sitting at 150% to 170% of the norm, Moser said, according to SNOTEL data.

“Across the northern part of the Upper Colorado River Basin, there’s been alternating periods of sunny, warm weather that generates the snow melt and the higher ows,” he said. “And then we’ve seen those pe- riods alternating with cooler, cloudier weather that’s brought some additional moisture in both rain and snow. It’s helped the snowmelt rate decrease, so it’s been kind of up and down in April and May.” at thick layer is also frequently downstream of reservoirs which means, depending on the location, the water is going straight into streams and rivers. at has led to an extended period of high ows, especially in the WhiteYampa River Basin in northwestern Colorado and the Dolores River Basin, Moser said. And when rain falls onto snow, as it has in isolated patches across the state, the liquid water speeds up melting even further.

Southwestern Colorado has seen more continuous warm, sunny weather and thus more snowmelt than other parts of Colorado, like the northwestern region, he said.

Colorado also received higherthan-normal snowpack across elevations lower than 9,500 feet, where snow typically melts more quickly.

“We’ve entered into a period of showers and thunderstorms in the afternoons and evenings,” he said. “We’ve had some enhanced melt due to rain-on-snow with some of these storms.” ese sites target between 9,000 and 11,500 feet where most of the snow- pack typically accumulates. at’s why the snow-water equivalent percentages from SNOTEL data have not changed by much, he said. e Colorado Sun co-owns Colorado Community Media as a partner in the Colorado News Conservancy. It is a reader-supported news organization dedicated to covering the people, places and policies that matter in Colorado. Read more, sign up for free newsletters and subscribe at coloradosun.com.

SNOTEL sites are generally located above 9,000 feet so lower elevation runo isn’t re ected in basinwide snow-water equivalent percentages.

“ ere’s still a lot of high-elevation snow up there,” Moser said.