Snowpack heads south in some areas
With two months remaining in the official 2010-11 snow year, April surveys indicate the snowpack statewide is 113 percent of average, 28 percent greater than the snowpack one year ago.
However, snow totals vary widely from north to south.
According to the Natural Resources Conservation Service, snowpack readings in the northern and central mountains increased significantly during March but declined sharply across the southern mountains.
“It was a month where the rich got richer, and the poor just got poorer,” said Allen Green, NRCS state conservationist.
An indication of the abundant snow the northern half of the state has received in this winter of La Nina conditions in the southern Pacific Ocean, Steamboat Ski Resort on Monday announced a summit base measurement of 138 inches. That’s 11.5 feet, surpassing the previous record of 137 inches set during the 1996-97 season.
Snowpack surveyed on April 1 ranged from 135 percent of average in the North Platte Basin to 76 percent in the Rio Grande Basin.
The Gunnison Basin snowpack was 115 percent of average and 22 percent over last year, while the Colorado Basin was 130 percent of average and 72 percent above last year.
Green said it’s possible but “extremely remote” that snow conditions may improve in the southern basins, where the maximum snowpack normally is reached in early April.
Reservoir storage across the state on April 1 averaged 103 percent of long-term average but only 98 percent of last year’s storage on the same date.
Some of that lower reservoir capacity is to make room for whatever runoff comes this season, said Dan Crabtree, lead hydrologist with the U.S. Bureau of Reclamation in Grand Junction.
The bureau office in Grand Junction oversees operations of the three Aspinall Unit dams on the Gunnison River: the Blue Mesa, Morrow Point and Crystal dams.
“That’s typical of what happens when we have snow conditions like this year and anticipate a high runoff,” Crabtree said. “We increase our releases to make room for what we anticipate coming into Blue Mesa.”
The bureau recently announced flows into the Gunnison Gorge and the Black Canyon of the Gunnison River are at 1,400 cubic feet (or 10,470 gallons) per second, 2.5 times what they were last year at this time when flows were 530 cfs.
“The flows are significantly higher this year to make room for that anticipated runoff,” Crabtree said.
Recent runoff forecasts from the National Weather Service Colorado Basin River Forecast Center in Salt Lake City predict 800,000 acre-feet of unregulated runoff entering Blue Mesa. One acre-foot is about 326,000 gallons.
That’s substantially more than last year’s April 1 forecast, which called for 560,000 acre-feet entering Blue Mesa.