Upper Yellowstone snowpack is well above average (slideshow 2)
By Liz Kearney
With this winter’s La Niña weather pattern, snowpack around Montana — including the Upper Yellowstone River drainage — is breaking records.
The Upper Yellowstone snowpack measures 148 percent of normal, Lucas Zukiewicz, a Natural Resources Conservation Service water supply specialists, said Feb. 8.
In fact, some snow telemetry — SNOTEL sites — in the Boulder River drainage are way above normal for this time of year.
“Two sites — Monument Peak and Box Canyon — have already reached by Feb. 1 what we expect for peak snowpack in April or May,” he said.
And the Fisher Creek SNOTEL site north of Cooke City has the second deepest snowpack in 20 years of record for snow-depth measurements, with 104” of settled snowpack on the ground, Zukiewicz wrote in his monthly Water Supply Outlook Report.
“That’s DEEP!” he wrote.
And snowpack is above normal across the region.
“On the Upper Yellowstone, Cooke City and areas further east and into the Park, they are seeing the second-highest snowpack for Feb. 1 on record for a lot of the SNOTEL sites,” Zukiewicz said. “Last year was really good, but didn’t pick up until later. We’re well above where we were for Feb. 1 last year.”
The snowpack across the rest of Montana remains in good shape, with all basins at near to above normal for the date. In fact, Montana is the only state in the 12 western U.S. states where the USDA Natural Resources Conservation Service measures snowpack in which all basins in the state have at least normal snowpack conditions on Feb 1, according to NCRS news.
“La Niña weather patterns this year have favored the northern tier states across the western U.S. and so far Montana and Wyoming have been the big winners,” Zukiewicz said in the release.
Building on a strong early season snowpack, the month of January provided consistent moisture to the basins in the state, although storms from the West Coast came in with above normal temperatures. Many mountain locations were 3 to 7 degrees Fahrenheit above average for the month of January, which resulted in a mix of snow and rain through the month west of the Divide. Mid-month, the rain levels reached mid to high elevations, raining over an inch on the mountain snowpack in some locations.
“Even with the warmer than average weather, the mountain snowpack stood strong through the month with little to no discharge at water yielding elevations,” Zukiewicz said in the release. “The water was stored in the snowpack until runoff in the spring, thanks to a cold snowpack in place from the month of December.”
The snowfall for the overall water year, which begins Oct. 1, hasn’t been record-breaking in most locations, but has been above normal, according to NRCS data. Percentage-wise, other basins well above normal include the Upper Clark Fork at 140 percent of normal; Missouri Mainstem near Helena at 148 percent; and Gallatin River basins at 129 percent.
All of this amounts to great information to water users in the state, but a healthy dose of caution is still warranted, Zukiewicz said in the release.
“Getting complacent, or bragging about snowpack at the beginning of February would be like bragging about leading Daytona halfway through the race,” he said. “It doesn’t matter where you are halfway through it, it matters where you’re at when it wraps up.”
Snowpack typically peaks across the state during April or May. The coming months are critical for water supply, and in many basins east of the Divide the months of March, April and May typically provide significant precipitation.
“Should La Niña and associated weather patterns continue to favor the state with above normal snowfall, or even normal snowfall from this point, water supply could be more than adequate for irrigation and recreation this summer,” Zukiewicz said. “But if the pattern takes a turn, and the snow faucet shuts off, the prospects of our water supply would be diminished.”
Snowpack will continue to be closely monitored through the spring by the NRCS. The next snowpack and water supply update will be issued during the first week in March.
Monthly Water Supply Outlook Reports can be found at the website below after the fifth business day of the month: http://www.nrcs.usda.gov/wps/portal/nrcs/main/mt/snow/waterproducts/basin.