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

Roaring Fork basin snowpack boosted to 131% of median

Snowpack in the Roaring Fork basin now exceeds the basin-wide median seasonal snow-water equivalent peak of 17.1 inches, which typically occurs in mid-April, after this weekend’s storm. Snowpack in the basin reached an average of 18.5 inches of snow-water equivalent per site on March 12 or 131% of median according to NRCS. Snowpack gained between one and three inches at each station after this weekend’s snowfall.

SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 101.4% of average on March 12 with a “snow water equivalent” (SWE) of 14.5 inches, up from 13 inches on March 5 with most of the increase happening over the weekend. Last year on March 12, 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 22.9 inches on March 12, or 143.1% of average. That’s up from a SWE of 21.6 inches on March 5. Last year, on March 12, the station measured a snowpack holding 13.4 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 15.2 inches of SWE on March 12, or 115.2% of average.

Snowpack at Schofield Pass, which boasts some of the largest SWE accumulations in the basin, reached 37.7 inches on March 12, which represents 126.1% of average. Snowpack gained 3.3 inches over the weekend — the largest increase of SWE among these five Roaring Fork basin stations. Schofield Pass sits at an elevation of 10,700 feet between Marble and Crested Butte.

Snowpack at that site now exceeds the 35.1 inch median seasonal peak, which typically doesn’t come until mid April. McClure Pass, which as we reported last week is seeing especially high snowpack readings this winter like other mid elevations stations, topped its median seasonal peak of 16.6 inches of SWE on Feb. 14 this year.

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 hits new low

Lake Powell‘s storage is at its lowest level recorded since it began filling in the 1960s. On March 12, the reservoir was 21.74% full (with a total capacity based on a 1986 sedimentation survey) or 22.68% full (based on updated 2017-18 sedimentation data). That’s down from March 5, when the nation’s second-largest reservoir was at 21.82% of capacity (1986 data) or 22.76% (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 March 12, 2022, it was 24.44% full (based on 1986 data).

On March 12, Lake Powell’s elevation reached 3,520.5 feet, or 179.5 feet from full pool, down from 3,520.8 feet on March 5. The reservoir’s water level on March 12 was 4.5 feet below the target elevation of 3,525. In the last water year, Powell’s surface elevation peaked at 3,539.84 feet on July 3, after it dipped to what was then its lowest level since filling of 3,522.24 on April 22. Last year, on March 12, the reservoir reached 3,525.28 feet in elevation, or 174.72 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 on the rise

High air temperatures at the Aspen airport increased from 27°F on Feb. 28 to 45°F on March 6, which is about six degrees above normal, before dropping to 38°F on March 10. Meanwhile, low temperatures increased from 5°F on March 2 to 18°F on March 10, which is 1.5 degrees above normal.

One day of ‘moderate’ air quality reported last week in Aspen

The air quality in Aspen was “good” last week except for one day on March 6 when the AQI index was in the “moderate” range with 51 for ozone. For the remainder of the week, the AQI index for ozone ranged from 36 on March 10 to 47 on March 7.

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,...