Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.
Single-digit snowpack for McClure Pass
Snowpack in the Roaring Fork basin is dropping as temperatures are going up. Snowpack went from 16.4 inches of snow-water equivalent per site on April 14 to 14.8 inches on April 21, or 103% of median, according to NRCS.
SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 108.3% of median on April 21 with a “snow water equivalent” (SWE) of 16.9 inches, down from 17.5 inches and slightly up from 108% of normal on April 14. Last year on April 21, the SNOTEL station up the pass (located at elevation 10,600 feet) recorded an SWE of 16.6 inches.
The monitoring station at McClure Pass, located at elevation 8,770 feet, recorded a SWE of 8.7 inches on April 21 or 70% of median. That’s down from last week’s SWE of 12 inches. Last year, on April 21, the station measured a snowpack holding 25.7 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 20.8 inches of SWE on April 21, or 125.3% of median.
Snowpack at North Lost Trail, which sits at an elevation of 9,219 feet, has reached 12.7 inches of SWE on April 21, which is down from 15.7 inches on April 14.
Snowpack at Schofield Pass reached 29.9 inches on April 21, which represents 95% of median. That’s down from 31.5 inches on April 14. 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.
Twin Lakes diversion started last week
At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 42.6 cfs on April 21, or 77.5% of average, down from last week when the river ran at 46.3 cfs and 107.7% of average.
Water through the tunnel that sends Roaring Fork flows east of the Continental Divide ran at 27.2 cfs on April 21, up from 4.2 cfs on April 14.
The USGS sensor below Maroon Creek recorded the Fork running at 155 cfs on April 21, or 116.5% of average, up from 149 cfs but down from 130.7% of average, on April 14.
At Emma, below the confluence with the dam-controlled Fryingpan, the April 21 streamflow of 479 cfs represented about 109.9% of average. That’s up from 476 cfs on April 14 but down from 123.6% of average.
Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 238 cfs or 94.4% of average. Last week, the river ran at 258 cfs, or 144.1% of average.
The Colorado River ran at 3,210 cfs at Glenwood Springs, or 109.6% of average, on April 21, up from 2,800 cfs last week, while the Colorado flowed at 5,330 cfs near the Colorado-Utah stateline, or 81.7% of average.
Lake Powell’s water levels begin to increase
Lake Powell‘s water levels peaked in early July and are now decreasing. On April 21, the reservoir was 32.93% full (based on updated 2017-18 sedimentation data). That’s up from April 14 when the nation’s second-largest reservoir was at 32.87%.
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 21, 2023, the reservoir was 23.55% full.
On April 21, Lake Powell’s elevation reached 3,558.5 feet, or 141.5 feet from full pool, which is up from 3,558.3 feet on April 14. Last year, on April 21 the reservoir reached 3,524.07 feet in elevation, or 175.93 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.