Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.

Streamflows on the rise

Streamflows in the Roaring Fork basin are up from last week.

Aspen Journalism is also compiling real time streamflow data. You can find all the featured stations from the dashboard with their real-time streamflow on this webpage.

At Stillwater, located upstream of Aspen, the Fork ran at 54.8 cfs or 71.2% of average on April 30. That’s up from 40.1 cfs and 65.7% of average, on April 23.

The USGS sensor on the Roaring Fork river below Maroon Creek recorded the Fork running at 187 cfs on April 30, or 78.9% of average. That’s up from 138 cfs on April 23.

At Emma, below the confluence with the dam-controlled Fryingpan, the April 30 streamflow of 550 cfs represented about 102.2% of average. That’s up from 364 cfs, and 78.3% of average, on April 23.

The transbasin diversion that sends Roaring Fork basin headwaters to Front Range cities was flowing at 13.7 cfs on April 30.

Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 548 cfs, or 158.4% of average, on April 30. Last week, the river ran at 195 cfs, or 71.1% of average.

Snowpack goes down but still well above normal

Snowpack in the Roaring Fork basin is relatively unchanged from last week, reaching an average of 19.4 inches of snow-water equivalent per site on April 30, or 154% of median, according to NRCS.

SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 100.6% of median on April 30 with a “snow water equivalent” (SWE) of 16.1 inches, up from 17.3 inches and 112.3% of normal on April 23. Last year on April 30, the SNOTEL station up the pass (located at elevation 10,600 feet) recorded an SWE of 12 inches.

The monitoring station at McClure Pass, located at elevation 8,770 feet, recorded a SWE of 23.3 inches on April 30, or 274% of median. That’s down from a SWE of 26 inches on April 23, but up from 217% of median. Last year, on April 30, the station measured a snowpack holding 4.4 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 19.2 inches of SWE on April 30, or 119.3% of median.

Snowpack at North Lost Trail, which sits at an elevation of 9,219 feet, has reached 23.4 inches of SWE on April 30, or 249% of median, down from 24.1 inches last week.

Snowpack at Schofield Pass reached 52 inches on April 30, which represents 165.6% of median. 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 water level doesn’t change much

Lake Powell‘s water levels began their seasonal rise in mid-March as warming temperatures initiated snowmelt, after the reservoir in the winter dropped to its lowest level on record since filling. On April 30, the reservoir was 22.8% full (with a total capacity based on a 1986 sedimentation survey) or 23.78% full (based on updated 2017-18 sedimentation data). That’s down from April 23, when the nation’s second-largest reservoir was at 22.87% of capacity (1986 data) or 23.86% (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 April 30, 2022, it was 23.81% full (based on 1986 data).

On April 30, Lake Powell’s elevation reached 3,525 feet, or 175 feet from full pool, down from 3,525.3 feet on April 23. The reservoir’s water level on April 30 hit the target elevation of 3,525. Last year, on April 30, the reservoir reached 3,522.77 feet in elevation, or 177.23 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.

Air temperatures at ASE start to rise

High air temperatures at the Aspen airport increased from 32°F on April 20 to 38°F on April 22, or 16 degrees below normal. Meanwhile, low temperatures went from 8°F on April 20 to 24°F on April 22.

Better air quality last week

The air quality in Aspen was “moderate” for three days last week, on April 24, 28 and 30, when the AQI index for ozone reached up to 54. For the remainder of the week, the AQI index ranged from 44 on April 26 to 47 for ozone on April 29.

Laurine Lassalle is Aspen Journalism’s data desk editor, where she works to catalogue and analyze local public data. She also heads our our “Tracking the Curve” project, documenting COVID-19 in Pitkin,...