Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated at least weekly by mid-day Tuesday.

Lake Powell has gained more than three inches since last week

Lake Powell‘s storage remains at one of its lowest levels recorded since it began filling in the 1960s and ’70s. However, for the first time since last spring, the amount of water stored in the reservoir increased over the past week, as the annual runoff boosted river flows.

On May 1, the reservoir was 23.79% full. Last week, on April 24, it was 23.72% full. The reservoir’s capacity has fallen since last year, when on May 1, 2021, the reservoir was 34.93% of full.

The surface elevation of Lake Powell dipped below the target elevation of 3,525 feet on March 15, but it gained 3.6 inches between April 24 and May 1. On May 1, Lake Powell’s elevation reached 3,522.7 feet, or 177.3 feet from full pool, up from 3,522.4 feet on April 24. Last year, on May 1, the reservoir reached 3,562.26 feet, or 137.74 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 Crystal River is flowing above average

“Streams were flowing below average until last week, when warm temperatures produced the highest flows of the season,” the Roaring Fork Conservancy noted in its snowpack and river report of April 27. “This was followed by last weekend’s cool temperatures and precipitation, which slowed down the snow melt and dropped stream flows again.”

The USGS gauge on the Roaring Fork River near Aspen at Stillwater, located upstream of town, measured streamflow at 58.9 cfs on May 1, which represents 71% of average. That’s down from last week, when the river was flowing at 64.6 cfs. On May 1, 2021, the river ran at 81.9 cfs.

The Crystal River above Avalanche Creek, near Redstone, flowed at 495 cfs, or about 134.5% of average, on May 1. The warmer temperatures of last week increased the streamflow of the river as the Crystal jumped from 294 cfs on April 26. The Crystal River at the CPW Fish Hatchery bridge ran at 604 cfs on May 1, up from 348 cfs on April 26.

Snowpack at McClure contains about three inches of water, down from eight inches last week

Snowpack in the Roaring Fork Basin was at 84% of average, according to NOAA on May 1. It’s been below average since April 20, reaching that designation for the first time this season, the Roaring Fork Conservancy wrote on April 21.

SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 73.9% of average on May 1, with a “snow water equivalent” (SWE) of 11.3 inches. The size of the snowpack relative to the 30-year average is up from last week’s 73.7%. Snowpack dropped from over 12 inches on April 30 to about 11 inches on May 1 due to warmer temperatures. Last year on May 1, the SNOTEL station up the pass recorded an SWE of 9.49 inches.

The monitoring station at the lower-elevation McClure Pass recorded a SWE of 3.11 inches, or 31.4% of average, on May 1. A week before, the station reported 7.9 inches of water contained in the snowpack, or 63.8% of average. Last year, on May 1, the station measured a snowpack holding 0.12 inches of water, or 1.2% of average.

On the northeast side of the Roaring Fork Basin, snowpack at Ivanhoe contains higher water levels than the 1991-2020 average, with 17.01 inches on May 1, which is 105.6% of the average of 16.1 inches. It dropped from 17.1 inches of SWE on April 24. It’s up from last year’s 15.59 inches of SWE.

Snowpack at Schofield Pass reached 32.2 inches on April 24, which represents 95% of average. For the first time this year, Schofield Pass’ snowpack is below 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.

‘Moderate’ air quality reported in Aspen last week as wildfires reported to the south

The air quality in Aspen was “moderate” this past week. The AQI index for ozone ranged from 51 on April 27 to 84 on April 26. Declining air quality last week coincided with drought-fueled early season wildfires burning in northern New Mexico.

Maximum air temperature dropped 30 degrees within one day

Temperatures dropped dramatically around April 23-24. Maximum air temperature went from 68°F on April 22 to 33°F on April 23, which is 21.5 degrees below normal, before going back to 62 on April 26, according to temperatures recorded at the Aspen/Pitkin County Airport. The minimum was closer to normal. It ranged from 27°F on April 26, which is about three degrees below normal, to 36°F on April 27, about six degrees above normal.

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,...