JACKSON, Wyo. (AP) - Runoff from melting mountain snow has surged in recent days and may peak earlier than normal because of unusually warm weather for this time of year, a water manager says.

The runoff is "a whole month earlier than the averages," said Mike Beus, Bureau of Reclamation water operations manager for the Snake River.

A warming trend accelerated Monday when the overnight temperature dipped only to 36 degrees, and on Wednesday the overnight low settled at 41 degrees.

In that same period, Snake River flows measured above Palisades Reservoir jumped 62 percent, increasing from 3,200 to 5,200 cubic feet per second.

While warm temperatures caused the recent surge in flows, other factors decide when the runoff peaks. Although the Snake River basin has received 78 percent of average precipitation since Oct. 1, the water content of the snowpack sits at only 45 percent of average.

"It's not that we're incredibly dry, but that we're seeing the snowmelt runoff incredibly early," Beus said. "This may well be the peak coming up in the next few days."

AP-WS-05-06-04 1331EDT