Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.
Snowpack at McClure Pass gets below 4 inches of snow-water equivalent
Snowpack in the Roaring Fork basin is dropping as temperatures are going up. Snowpack went from 14.8 inches of snow-water equivalent per site on April 21 to 11.9 inches on April 28, or 91% of median, according to NRCS. Snowpack went as low as 10.9 inches on April 26-27 before going back up and gaining about two inches during this weekend’s snowstorm.
SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 87.2% of median on April 28 with a “snow water equivalent” (SWE) of 14.3 inches, down from 16.9 inches and from 108.3% of normal on April 21. Last year on April 28, the SNOTEL station up the pass (located at elevation 10,600 feet) recorded an SWE of 17.5 inches.
The monitoring station at McClure Pass, located at elevation 8,770 feet, recorded a SWE of 3.8 inches on April 28 or 39% of median. That’s down from last week’s SWE of 8.7 inches. Last year, on April 28, the station measured a snowpack holding 24.9 inches of water.
On the northeast side of the Roaring Fork Basin, snowpack at Ivanhoe, which sits at an elevation of 10,400 feet, reached 20.9 inches of SWE on April 28, or 129% of median.
Snowpack at North Lost Trail, which sits at an elevation of 9,219 feet, has reached 7.9 inches of SWE on April 28, which is down from 12.7 inches on April 21.
Snowpack at Schofield Pass reached 25.6 inches on April 28, which represents 83% of median. That’s down from 29.9 inches on April 21. Schofield Pass sits at an elevation of 10,700 feet between Marble and Crested Butte.
Snow water equivalent — the metric used to track snowpack — is the amount of water contained within the snowpack, which will become our future water supply running in local rivers and streams.
Streamflows are up from last week but have slowed down over the weekend
At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 62 cfs on April 28, or 88.6% of average, up from last week when the river ran at 42.6 cfs and 77.5% of average. The Fork reached 100 cfs at Stillwater on April 25.
Water through the tunnel that sends Roaring Fork flows east of the Continental Divide ran at 47.7 cfs on April 28, down from 76.3 on April 27 but up from 27.3 cfs on April 21.
The USGS sensor below Maroon Creek recorded the Fork running at 225 cfs on April 28, or 109.8% of average, up from 155 cfs but down from 116.5% of average, on April 21.
At Emma, below the confluence with the dam-controlled Fryingpan, the April 28 streamflow of 630 cfs represented about 127.3% of average. That’s up from 479 cfs on April 21 and from 109.9% of average.
Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 298 cfs or 96.1% of average after reaching 519 cfs on April 25. Last week, the river ran at 238 cfs, or 94.4% of average.
The Colorado River ran at 4,910 cfs at Glenwood Springs, or 141.5% of average, on April 28, up from 3,210 cfs last week, while the Colorado flowed at 8,140 cfs near the Colorado-Utah stateline, or 107.7% of average.
Lake Powell’s water levels are up
Lake Powell‘s water levels peaked in early July and are now decreasing. On April 28, the reservoir was 33.22% full (based on updated 2017-18 sedimentation data). That’s up from April 21 when the nation’s second-largest reservoir was at 32.93%.
On July 1, 2022, the Bureau of Reclamation revised its data on the amount of water stored in Lake Powell, with a new, lower tally taking into account a 4% drop in the reservoir’s total available capacity between 1986 and 2018 due to sedimentation. Aspen Journalism in July 2022 published a story explaining the that drop in storage due to sedimentation. We will be now using the 2017-18 sedimentation data only.
On April 28, 2023, the reservoir was 23.57% full.
On April 28, Lake Powell’s elevation reached 3,559.4 feet, or 140.6 feet from full pool, which is up from 3,558.5 feet on April 21. Last year, on April 28 the reservoir reached 3,524.1 feet in elevation, or 175.9 feet from full pool.
The “minimum power pool” for turbines generating hydropower at the Glen Canyon Dam is 3,490 feet, and 3,525 feet has been set as a buffer to ensure that the reservoir and the turbines can continue to function properly.