The snow pack in the Rocky Mountains provides far more than excellent skiing. Melted snow from the Rocky Mountains supplies drinking water for about 70 million Americans, but a study by the U.S. Geological Survey warns that warmer springs have reduced snow cover in the mountains by 20 percent since 1980.
The decline in snow cover was most extreme in the north. Snow cover was also significantly reduced in the low and middle latitudes.
Reductions in snow cover and changes in the timing of the annual melt also threaten electricity production from hydroelectric dams as well as irrigation water. The changes may also alter the risks of fire and flood in the American West.
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"Each year we looked at temperature and precipitation variations and the amount of water contained within the snow pack as of April," said lead author and USGS scientist Greg Pederson in a press release. "From 1980 on, warmer spring temperatures melted snow pack throughout the Rockies early, regardless of winter precipitation. The model in turn shows temperature as the major driving factor in snow pack declines over the past thirty years."