Snowpack below average for winter season

The snowpack is below average in the Big Horn Mountains, according to Jeff Coyle, Water Supply Specialist for the USDA Natural Resources Conservation Service (USDA-NRCS) Wyoming Snow Survey. 

“Right now, if you’re talking about the Big Horn Mountains, the snowpack is not doing very well. And a lot of it ranges from 60 to 80% (of median). But there’s a lot of near record lows,” Coyle said. 

The Big Horn Basin is at 77 percent of median for snow water equivalent, according to the February 26 USDA-NRCS snow report. The weighted state average for snowpack is 81 percent of the median. 

A snow dump was predicted to bring 7 to 12 inches of snow in the Big Horn Mountains this past weekend, but only resulted in precipitation ranging from one to two inches throughout the mountains, Coyle said. 

Certain sites are still reporting above average snowpack, with the Greybull sub-basin SNOTEL sites in the Timber Creek drainage and near Carter Mountain reporting snowpack above 150% of median, he said. The Owl Creek drainage and Wind River Basin snowpack are around 100%. 

The water year, which is a measure of annual precipitation, begins October 1 in Wyoming, Coyle said. While snowpack this water year is below average, precipitation for the current water year is near median for the Big Horn Mountains, due to early precipitation in October that is now in reservoir storage or soil moisture. 

Reservoirs near the Big Horn Basin area range from a bit below median to a bit above median, Coyle said. Measurements near Thermopolis are at a deficit, with precipitation at 80 to 90 percent of the median. Areas surrounding Greybull and Lovell, are a mixed bag ranging from 80 to 110 percent of the median precipitation. 

More specifically, the precipitation of the Big Horn Basin is at 98 percent of median, while the Tongue River drainage is at 101 percent of median, he said. 

Stream forecasts surrounding the Big Horn Basin are predicted to be near the median as a whole, Coyle said. However, Greybull is forecast to be above median. 

“Greybull (river) is going to do a lot better. Because right now they’re forecasted to have an excess amount of moisture, and that’s an important river, as far as they’re drawing from the major reservoirs for irrigation and things like that,” he said. 

Shell Creek is forecast to be below median while the Big Horn River is forecast to be around median, due to contributing stream flows from the Wind River Basin, Owl Creek drainage and Greybull River, Coyle said. 

Despite the low snowpack thus far, it is too early to determine what the overall water year will look like for the Big Horn Basin, he said. The winter is not over, and there could be more snowpack. 

“The forecasts become more accurate later in the year, usually around late March, April,” Coyle said. “We get so much snow in that time period that sometimes it makes or breaks us.”