Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly by mid-day Tuesday.
Soil moisture showing signs of improvement
The Aspen Global Change Institute maintains a network of monitoring stations throughout the Roaring Fork watershed that track soil-moisture levels. The station in Glenwood Springs measures soil moisture at a 2-inch and an 8-inch depth. While the 8-in depth measurement captures changes in soil moisture across seasons, drying events and moderate or heavy rains, the 2-inch depth data also reflects air temperature.
In early 2022, the soil at the Glenwood Springs station was moister than the 2016-2020 average at the start of the year for both depths. On Jan. 4, 2022, the Glenwood Springs station recorded an average of 0.24 m3/m3 of water for the day at 2-inch depth, compared to 0.17 m3/m3 on average between 2016 and 2020. On that same day, the station measured an average of 0.28 m3/m3 of water at 8-inch depth, higher than the 2016-2020 average of 0.21 m3/m3.
In contrast, 2021 started the year drier than the average for both depths.
Throughout February, the soil became drier than the average, but moisture increased exceeded the four-year average in March.
While the monitoring station at Sky Mountain Park recorded a similar pattern at the start of the year, the soil was drier than the average for a longer period of time, from February to April for both depths.
Last year, conditions were particularly dry in mid-April and May for most stations. This year, the soil moisture at the Glenwood Springs station was closer to the average.
On May 24, 2022, the soil contained 0.13 m3/m3 of water at 2-inch depth at the Glenwood Springs station, up from last year’s 0.11 m3/m3, but lower than the 2016-2020 average of 0.18 m3/m3. At 8-inch depth, the Glenwood Springs station recorded 0.24 m3/m3 of water, compared to about 0.25 on average between 2016 and 2020. That’s up from last year’s 0.17.
Local streamflow swinging as temperature varies
The USGS gauge on the Roaring Fork River near Aspen at Stillwater, located upstream of town, measured streamflow at 198 cfs on Monday, May 30, which is 60.7% of average. The Fork ran as high as 229 cfs on May 28 before dropping to 198 cfs on May 30 due to the cooler temperatures of the holiday weekend. On May 30, 2021, the river ran at 197 cfs.
The Crystal River above Avalanche Creek, near Redstone, flowed at 1,050 cfs, or about 91.3% of average, on May 30. The Crystal reached up to 1,370 cfs on May 28. The Crystal River at the CPW Fish Hatchery bridge flow dropped to 702 cfs on May 25 before jumping to 1,620 cfs on May 28, and then going down to 1,330 cfs on May 30.
Seasonal peak flows on most local rivers may have occurred around May 19, when the Fork at Stillwater ran at 319 cfs and the Crystal near Redstone ran at 2,030.
Snowpack sees a small bump over Memorial Day weekend
Snowpack in the Roaring Fork Basin was at 26% of average on May 30, according to NOAA. It’s slightly up from May 29’s 22% of average due to recent cooler temperatures. 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 12.1% of average on May 30, with a “snow water equivalent” (SWE) of 0.31 inches. The size of the snowpack relative to the 30-year average is up from last week’s 5.6%. Last year on May 30, the SNOTEL station up the pass (located at elevation 10,600 feet) recorded an SWE of 0 inches.
The monitoring station at McClure Pass recorded a SWE of 0.2 inches, or 28.1% of average, on May 30. A week before, the station reported 0.2 inches of water contained in the snowpack, or 10.9% of average. Last year, on May 30, the station measured a snowpack holding 0 inches of water.
On the northeast side of the Roaring Fork Basin, snowpack at Ivanhoe now contains lower water levels than the 1991-2020 average, with 0.39 inches on May 30, which is 9.2% of the average of 4.3 inches. It dropped to 0 inches of SWE on May 29 before going back up to 0.39 on May 30 due to cooler temperatures of the Memorial Day weekend. It’s up from last year’s 0 inches of SWE.
Snowpack at Schofield Pass reached 5.79 inches on May 30, which represents 32.7% of average. Schofield Pass’ snowpack has been below average for about a month. 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 three feet since last week
Lake Powell‘s storage remains at one of its lowest levels recorded since it began filling in the 1960s. However, the amount of water stored in the reservoir increased over the past month, as the annual runoff boosted river flows.
On May 30, the reservoir was 26% full. Last week, on May 22, it was 25.2% full. The reservoir’s capacity has fallen since last year, when on May 30, 2021, the reservoir was 34.34% of full.
The surface elevation of Lake Powell exceeded the target elevation of 3,525 feet on May 16, after dipping below it on March 15. On May 30, Lake Powell’s elevation reached 3,531.3 feet or 168.7 feet from full pool, up from 3,528.3 feet on May 22. Last year, on May 30, the reservoir reached 3,560.39 feet, or 139.61 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.
Aspen reported a temperature drop of about 20 degrees
Temperatures dropped on May 19. Maximum air temperature went from 73°F on May 19 to 48°F on May 21 before getting up to 55°F on May 24, which is about 10 degrees below normal, according to temperatures recorded at the Aspen/Pitkin County Airport. The minimum ranged from 30°F on May 20 and 21, which is about five degrees below normal, to 41°F on May 17, about six degrees above normal.
Air quality was ‘good’ in Aspen last week
The air quality in Aspen was “good” this past week besides May 23 when air quality was moderate and the AQI index for ozone reached 51. This decline in air quality was probably caused by wildfires burning in New Mexico and Arizona and prescribed burns across Colorado. Jannette Whitcomb, Aspen senior environmental health specialist, wrote in an email that it is commonplace to see moderate AQI for ozone in Aspen in the spring.
For the remainder of the week, the AQI index for ozone ranged from 36 on May 30 to 48 on May 24 and 25.
