Aspen Journalism is compiling a data dashboard highlighting metrics of local public interest, updated weekly.
The Roaring Fork’s upvalley streamflow has doubled since 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 Roaring Fork River ran at 276 cfs, or 113.1% of average on May 21. That’s up from 137 cfs and 86.7% of average on May 14.
The USGS sensor below Maroon Creek recorded the Fork running at 816 cfs on May 21, or 163.5% of average. That’s up from 409 cfs on May 14.
At Emma, below the confluence with the dam-controlled Fryingpan, the May 21 streamflow of 1,390 cfs represented about 125.2% of average. That’s up from 968 cfs, but down from 129.9% of average, on May 14.
The transbasin diversion that sends Roaring Fork basin headwaters to Front Range cities and farms was flowing at 336 cfs on May 21, up from 111 cfs on May 14.
Meanwhile, the Crystal River above Avalanche Creek, which is not impacted by dams or transbasin diversions, flowed at 1,490 cfs, or 156.7% of average, on May 21. Last week, the river ran at 963 cfs, or 147.2% of average.
The Colorado River ran at 11,300 cfs at Glenwood Springs, or 137.3% of average on May 21, up from 2,600 cfs last week, while the Colorado flowed at 32,900 cfs near the Colorado-Utah stateline, or 209.6% of average.
Some SNOTEL stations see big declines
Snowpack in the Roaring Fork basin has dropped from last week but remains well above normal for most sites, reaching an average of 8.3 inches of snow-water equivalent per site on May 21, or 160% of median, according to NRCS.
SNOTEL sites that monitor snowfall throughout the winter measured the snowpack at Independence Pass at 55.8% of median on May 21 with a “snow water equivalent” (SWE) of 2.9 inches, down from 9.7 inches and 95.1% of normal on May 14. Last year on May 21, the SNOTEL station up the pass (located at elevation 10,600 feet) recorded an SWE of 0.6 inches.
The monitoring station at McClure Pass, located at elevation 8,770 feet, recorded a SWE of 2.1 inches on May 21 compared to the median at zero inches. That’s down from a SWE of 10.2 inches on May 14. Last year, on May 21, the station measured a snowpack holding 0.5 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 7.3 inches of SWE on May 21, or 93.6% of median.
Snowpack at North Lost Trail, which sits at an elevation of 9,219 feet, has reached 5.8 inches of SWE on May 21, down from 11.6 inches last week.
Snowpack at Schofield Pass reached 36.7 inches on May 21, which represents 162.4% of median. That’s down from 44.2 inches on May 14. 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 rises nearly 10 feet in a week
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 May 21, the reservoir was 28.49% full (with a total capacity based on a 1986 sedimentation survey) or 29.72% full (based on updated 2017-18 sedimentation data). That’s up from May 14, when the nation’s second-largest reservoir was at 26.02% of capacity (1986 data) or 27.15% (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 May 21, 2022, it was 25.06% full (based on 1986 data).
On May 21, Lake Powell’s elevation reached 3,547.4 feet, or 152.6 feet from full pool, up from 3,538.1 feet on May 14. The reservoir’s water level on May 21 was 22 feet above the target elevation of 3,525. Last year, on May 21, the reservoir reached 3,527.73 feet in elevation, or 172.27 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.
High air temperatures remained in the mid-60s in mid-May
High air temperatures at the Aspen airport dropped from 68°F on May 10 to 47°F on May 11 before reaching 64°F on May 13, or about three degrees above normal. Meanwhile, low temperatures were around 35°F, which is close to normal.
Overall ‘good’ air quality in Aspen reported last week
The air quality in Aspen was “good” last week except on May 16 and 17 when the AQI index for ozone reached up to 51. For the remainder of the week, the AQI index ranged from 47 on May 18 to 50 for ozone on May 20.
