Posted: Thursday, April 20, 2006 12:00 am
CHEYENNE (AP) - Recent warm weather is melting snowpack across Wyoming faster than normal, state and federal officials say.
The Natural Resources Conservation Service reports that snowpack statewide dropped from 95 percent of average to 83 percent of average between April 10 and Monday.
"We're right at the time when the snowpack would peak, the middle of April, so it's not unusual that snowpack would be dropping this time of year," said Ed Kouma with the U.S. Bureau of Reclamation's Water Management Branch in Wyoming.
Harry LaBonde, deputy Wyoming state engineer, said Wednesday that weather in the last couple of weeks had been warmer than average, which has resulted in melting snowpack.
But, LaBonde said, "Whether that trend will continue or not, I'll defer to the weathermen."
LaBonde said there have been a number of reports in the last 10 years or so stating that peak runoff is occurring earlier in the springtime as a result of global warming.
On the Upper North Platte River, snowpack dropped from 107 percent to 98 percent of the historical average from April 10 to April 17. Snowpack on the Powder/Tongue River drainage dropped from 77 percent to 61 percent in the same period.
Only the upper Yellowstone River drainage increased its snowpack in the week, from 104 percent of average to 105 percent.
Whether the earlier runoff might affect farmers and ranchers this summer depends on where they are in a river system, LaBonde said.
On the North Platte, for example, LaBonde said agricultural users downstream of large federal reservoirs should be in good shape because the state is still predicting an above-average runoff year. But for upstream users, who rely on taking water directly from the natural flow of the river, supplies could be reduced later in the year if warm weather continues.
However, LaBonde cautioned against making long-term generalizations based on the weather patterns over the last few weeks. "I really wouldn't comment what it means later in August," he said. He said this year has still been a much better water year for Wyoming than the previous few years.