CODY, Wyo. — Portions of northern Wyoming are holding their own this winter when it comes to precipitation, even as other regions of the state and Yellowstone Park fall behind in snowpack.
The Shoshone and Clarks Fork river basins, along with the Powder and Tongue river systems east of the Bighorn Mountains, remain among the wettest in the state, reporting precipitation levels just above average.
But the Upper Yellowstone, Bighorn Basin and Wind River systems continue to lag, showing average to below-average precipitation totals this winter.
For James Fahey, a hydrologist with the National Weather Service in Riverton, it could be described as a tale of two winters.
“The winter of 2012 is already starting out quite differently than how the winter of 2011 started, especially in terms of snowpack across Wyoming,” Fahey said. “Snow production in the mountains has been low this December across the state.”
By the end of 2011, basins across Wyoming had received near normal to above-normal snowfall. Fahey said it’s far less than the totals measured at the same point in 2010.
Many basins across the state have already lost a month or more of snowpack production, he said. The short-term forecast shows little in the way of big snowmakers.
“This year has been nothing like last year,” Fahey said. “But it’s still early all around Wyoming. You get a couple storms, a couple of whoppers, and you’re back in business.”
By this time last year, precipitation levels in the Bighorn Basin were 106 percent of average, while the Shoshone and Clarks Fork systems were 112 percent of average. The Upper Yellowstone system was well ahead, at 127 percent.
By winter’s end, the region was sitting on a record snowpack that lingered deep into the spring thanks to cooler temperatures. April and May saw more wet snow fall during the peak runoff, priming area watersheds for heavy flows in June and early July.
What resulted went down in the record books. The Bighorn River near Basin achieved its highest flow ever recorded, while the South Fork of the Shoshone River near Valley reached its second-highest flow since 1957.
In Yellowstone Park, the Lamar River at Tower Junction achieved its fifth-highest flow since 1923, while Yellowstone Lake peaked six inches short of its 1997 record.
This week, snow telemetry readings at Blackwater above the North Fork of the Shoshone River showed 50 inches, while the station at Beartooth Lake on the Montana border read 47 inches.
In the Bighorn Mountains, the station at Bald Mountain read 40 inches, while the Shell Creek station read 37 inches.
But the snow-depth readings in Yellowstone tell a different story. The station at Canyon measured 29 inches Wednesday, compared with 36 inches on the same day last year.
Thumb Divide read 30 inches — 16 fewer inches than in 2011 — while Sylvan Lake showed a snow depth of just 39 inches; last Jan. 4, it read 45 inches.
“Watersheds east of the Continental Divide receive most of their snowpack in the spring,” Fahey said. “A lot can happen between now and May.”