Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.
Flows are well below average
At Stillwater, located upstream of Aspen, the Roaring Fork River ran at 50.2 cfs on May 12, or 36.4% of average, down from last week when the river ran at 73.8 cfs and from 71.7% of average.
Water through the tunnel that sends Roaring Fork flows east of the Continental Divide ran at 29.2 cfs on May 12, down from 37.7 on May 5.
The USGS sensor below Maroon Creek recorded the Fork running at 192 cfs on May 12, or 66% of average, down from 229 cfs and from 85.8% of average, on May 5.
At Emma, below the confluence with the dam-controlled Fryingpan, the May 12 streamflow of 474 cfs represented about 67.4% of average. That’s down from 554 cfs on May 5 and from 94.06% of average.
Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 206 cfs or 33.6% of average. Last week, the river ran at 311 cfs, or 67.2% of average.
The Colorado River ran at 3,910 cfs at Glenwood Springs, or 69.8% of average, on May 12, down from 4,720 cfs last week, while the Colorado flowed at 5,720 cfs near the Colorado-Utah stateline, or 47.3% of average.
Snowpack is slightly up form last week
Snowpack in the Roaring Fork basin is dropping as temperatures are going up. Snowpack went from 10 inches of snow-water equivalent per site on May 5 to 10.4 inches on May 12, or 117% of median, according to NRCS.
SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 94% of median on May 9 with a “snow water equivalent” (SWE) of 12.4 inches, down from 12.5 inches and from 86.8% of normal on May 5. Data for this station was unavailable for May 12, 2024.
The monitoring station at McClure Pass, located at elevation 8,770 feet, recorded a SWE of 0.5 inches on May 12 or 36% of median. That’s up from last week’s SWE of 0.3 inches. Last year, on May 12, the station measured a snowpack holding 12 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 21.7 inches of SWE on May 12, or 159.6% of median.
Snowpack at North Lost Trail, which sits at an elevation of 9,219 feet, has reached 4.6 inches of SWE on May 12, which is up from 4.1 inches on May 5.
Snowpack at Schofield Pass reached 26.4 inches on May 12, which represents 91% of median. That’s up from 24.8 inches on May 5. 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.
Lake Powell’s elevation has gained one foot of water since last week
Lake Powell‘s water levels are up. On May 12, the reservoir was 33.99% full (based on updated 2017-18 sedimentation data). That’s up from May 5 when the nation’s second-largest reservoir was at 33.69%.
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 May 12, 2023, the reservoir was 26.6% full.
On May 12, Lake Powell’s elevation reached 3,561.9 feet, or 138.1 feet from full pool, which is up from 3,560.9 feet on May 5. Last year, on May 12 the reservoir reached 3,536.04 feet in elevation, or 163.96 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.
Swinging air temperatures at ASE
High air temperatures at the Aspen airport went from 58°F on May 1 to 52°F on May 2 before going back up to 64°F on May 5. High air temperatures dropped to 39°F on May 8 before reaching 48°F on May 9, or 14 degrees below normal. Meanwhile, low temperatures ranged from 19°F on May 8 to 42°F on May 5.