Environment

Early Snow Melt - Wyoming, USA

The spring snowmelt now comes more than two weeks earlier than it did in the 1970s in Wyoming's Wind River Range, a new study finds.

The trend is part of a larger snow shortfall across the Western United States documented by many researchers. Several independent studies have found the spring snowmelt starts up to 20 days earlier in the West than in the past because there's less snow falling each winter and warmer spring weather means the snow that does fall melts earlier.

The snow is melting 16 days earlier this century than it was in the period from 1972-1999, the study found. Stream flows have decreased, and are also peaking earlier. Weather records from the same time period show a warming trend, with rising spring and summer nighttime temperatures. Higher nighttime temperatures can cause more snow to melt the next day, the study researchers said.

Water resources in states, such as Wyoming, that rely on snowmelt are being adversely affected.