Colorado snowpack still building, expert says
Colorado is awash when it comes to runoff this spring.
According to the latest snowpack surveys from the National Resources Conservation Service, the state’s snowpack remains well above long-term average and is the highest since 1966.
And the recent string of spring storms has those numbers on the rise.
“Things have been pretty interesting in the last month or more,” said Mike Gillespie, chief of the state NRCS snow survey. “We aren’t seeing any snowmelt and, in fact, are continuing to build snowpack on a daily basis.”
In addition to monthly manual snowpack surveys, Gillespie daily checks snowpack and precipitation data gathered by the state’s 108 remote SNOTEL (snowpack telemetry) sites.
The next manual survey, and the last one for this snow year, is set for May 1.
“In those years when we continue to build snowpack beyond the normal peak accumulation day, we see a much later melt out,” Gillespie said.
Based on 30 years of data, April 14 is the peak accumulation day for the Colorado River Basin, he said.
However, there has been “a sharp increase in snowpack almost daily for the last week,” Gillespie said. “The Colorado River Basin (snowpack) has not peaked yet for spring.”
The danger in an ever-increasing snowpack is that when temperatures again start to climb, as they surely will, the melt off may occur all at once.
“Normally, we see an early and a mid-level runoff before the high elevation runoff,” Gillespie said. “But when we have a cold spring and lots of moisture and then we hit normal temperatures and highs in the 80s and 90s, we have snowmelt at low, mid- and high levels occurring all at once. That’s always a problem.”
His forecasts project a runoff of 134 percent of average in the Colorado Basin.
Other forecasts include: Gunnison River, 109 percent; Yampa River, 157 percent; and the White River, 128 percent.
“We’ll likely make some progress in filling Lake Powell this year,” Gillespie said.