Northwest Wyoming has had a recent bout of precipitation, causing rivers to surge and mountaintops to be covered with another layer of spring snow. The rainfall is filling reservoirs and experts say it is looking like the summer will have plenty of water to keep Big Horn Lake near full pool.
An official observer at the Western Sugar factory in Lovell has recorded 2.09 inches of rainfall during the month of June in Lovell. The NWS said the reported rainfall is much more than the 0.99 inches of rain expected in Lovell for the entire month of June.
An official observer in Powell reported 1.49 inches of precipitation as of Tuesday for the month of June, according to the NWS. The normal total for the Powell reporting station for the entire month of June is 1.32 inches.
As the rain fell and made its way to rivers and streams, reservoirs began to rise and outflows were increased to keep water levels from rising too fast.
As of Tuesday at 8 p.m., Boysen Reservoir had outflows set at 3,230 cubic feet per second, contributing along with rainfall and side stream flows to 5,170 cfs of water moving through Big Horn Lake at Kane near the causeway, according to U.S. Bureau of Reclamation data. Another main tributary to the lake, Buffalo Bill Reservoir, was releasing 6,000 cfs Tuesday evening.
With inflows to Big Horn Lake around 11,000 cfs Tuesday, Bureau of Reclamation Montana Area Manager Dan Jewell said releases from Big Horn Lake have been stepped up over the past days to about 7,600 cfs as of 4 p.m. Tuesday.
He said the outflows were increased because the lake was rising by more than a foot a day. With less than 10 feet to full pool, he said a major event such as another large rainstorm could have put the reservoir over full pool. He said during the springtime, management is a day-to-day process.
“I don’t anticipate much higher outflows (from Big Horn Lake), but it depends on what happens at Boysen, Buffalo Bill and with the remaining runoff,” Jewell said.
At the current rate, Jewell said he expects Big Horn Lake to reach full pool of 3,640 in two or three weeks. FOBHL member Bob Croft agreed and said full pool should be reached just in time for the Big Horn Lake Celebration on June 20. As of Tuesday, the lake was at an elevation of 3,632.8 feet.
Big Horn County Emergency Management Coordinator John Hyde said the increased volume of water can be dangerous and he cautioned boaters to wear life jackets and exercise caution when taking to the water. He said low branches, logs and trees hanging over the high water can unexpectedly sweep boaters into the water.
During the wet weather Saturday and Sunday, there was plenty of cold air for significant snowfall of 5 to 10 inches across the northwest and northern mountains including Yellowstone National Park and the Big Horn Mountains, according to the NWS.
There was enough cold air for the lower elevations of the Big Horn Basin to receive snow. Snow was recorded in Greybull and Worland, but the bulk of the snow in the Big Horn Basin fell in the Cody foothills and extreme northern Big Horn County where one to three inches fell. 

The June 1 forecast of the spring snowmelt runoff indicates below average April through July snowmelt runoff can be expected at all forecast locations within the Big Horn Basin in Wyoming except the Shoshone River inflow to Buffalo Bill Reservoir, according to the Wyoming Area Office of the Bureau of Reclamation in Mills.
The Shoshone River portion of the Big Horn River Basin forecasted inflow to Buffalo Bill Reservoir during the April through July period is 720,000 acre-feet (AF) (111 percent of average). Approximately 298,000 AF of the forecasted amount flowed into Buffalo Bill Reservoir in April and May, leaving 422,000 AF of inflow forecasted for June through July.
In the Wind River portion of the Big Horn River Basin, the April through July snowmelt runoff into Bull Lake Reservoir from Bull Lake Creek is expected to be 130,000 AF (94 percent of average), of which 34,000 AF was received in April and May; and the snowmelt runoff into the Wind River above Bull Lake Creek is expected to be 350,000 AF (88 percent of average), of which 128,000 AF was received in April and May.
The forecasted inflow to Boysen Reservoir for the April through July period is 480,000 AF (89 percent of average), of which 183,000 AF was received in April and May, leaving 297,000 AF of runoff forecasted for June through July.