Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.
Early Roaring Fork Basin snowpack is above average and up from last year
After last week’s snowfall, snowpack in the Roaring Fork basin reached 185% of average for Nov. 6 with 2.6 inches of snow-water equivalent, according to NOAA.
SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 115.9% of average on Nov. 6, with a “snow water equivalent” (SWE) of 2.09 inches. Last year on Nov. 6, the SNOTEL station up the pass (located at elevation 10,600 feet) recorded an SWE of 1.61 inches or 87.7% of average.
The monitoring station at McClure Pass recorded a SWE of 2.99 inches on Nov. 6, or three times the average after recent snowfall and dropping temperatures. Last year, on Nov. 6, the station also measured a snowpack holding 0.39 inches of water.
On the northeast side of the Roaring Fork Basin, snowpack at Ivanhoe reached 2.8 inches on Nov. 6, or 164.4% of average.
Snowpack at Schofield Pass reached 3.9 inches on Nov. 6, which represents 134.4% of average. 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 Lake Tunnel diversion still on
The Roaring Fork River below Maroon Creek flowed at 118 cfs on Nov. 6, or 97.5% of average, according to the USGS gauge. That’s down from Oct. 30, when the river was flowing at 122 cfs, but up from 96.8% of average.
At Stillwater, located upstream of Aspen, the Fork on Nov. 6 ran at 18.8 cfs or 55.3% of average, up from 18.3 cfs and from 50.8% of average on Oct. 30. That put the river below the decreed minimum instream flow for the stretch of 35 cfs. The river’s streamflow dropped from 36.2 cfs on Oct. 18 to 17.8 cfs on Oct. 20, and has remained near that level ever since.
The Fork’s flow was impacted by the Independence Pass transbasin diversion system that sends Roaring Fork headwaters to Front Range cities. The diversion, which was curtailed for much of September to benefit senior downstream water rights, started back up around Oct. 20 as water was running at 26 cfs through the tunnel after it stopped around Oct. 14. Water flowing through the tunnel under the Continental Divide was running at at 23.6 cfs on Nov. 5.
The Roaring Fork at Emma, below the confluence with the dam-controlled Fryingpan, saw and Nov. 6 streamflow of 302 cfs, or about 93.5% of average. That’s down from 346 cfs, or 104.8% of average, on Oct. 30.
Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 83 cfs, or 107.8% of average, on Nov. 6. Last week, the river ran at 85 cfs, or 101.4% of average.
Lake Powell’s storage remains around 24% full
Lake Powell‘s storage remains at one of its lowest levels recorded since it began filling in the 1960s. On Nov. 6, the reservoir was 23.93% full (with a total capacity based on a 1986 sedimentation survey) or 24.96% full (based on updated 2017-18 sedimentation data). That’s down from Oct. 30, when the nation’s second-largest reservoir was at 23.98% of capacity (1986 data) or 25.01% (based on 2017-18 data).
On July 1, 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 published a story explaining the that drop in storage due to sedimentation.
The reservoir’s capacity has fallen since last year, when on Nov. 6, 2021, it was 29.43% full (based on 1986 data).
On Nov. 6, Lake Powell’s elevation reached 3,529.7 feet, or 170.3 feet from full pool, down from 3,529.9 feet on Oct. 30. The reservoir’s water level on Nov. 6 was about 4.7 feet above the target elevation of 3,525. Powell’s surface elevation this year peaked at 3,539.84 feet on July 3, after it dipped to its lowest level since filling of 3,522.24 on April 22. Last year, on Nov. 6, the reservoir reached 3,543.91 feet in elevation, or 156.09 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.
The air quality in Aspen was "good" last week with an AQI index for ozone ranging from 27 on Nov. 5 to 44 on Oct. 31.
- Colorado's Division of Water Resources
- Bureau of Reclamation
- Aspen Consolidated Sanitation District
- Aspen Global Change Institute