Snowpack Decline in Rockies Has Rapidly Accelerated, Study Shows

A new study says snowpack decline in the northern Rocky Mountains over the last 30 years has been more severe than at any other time in nearly 1,000 years. In an analysis of 66 tree-ring records, researchers from the U.S. Geological Survey (USGS) found that the average spring snowpack in the northern Rockies in recent decades has been even lower — and experienced a more prolonged decline — than two other low-snowpack periods, one in the early 14th century and another in the 16th century. The report, published in the journal Science, says the increasing role of warming on snowpack variability may foreshadow “fundamental impacts on streamflow and water supplies across the western United States.” Snowmelt from the Rockies drains into the Colorado, Columbia, and Missouri river basins, which together provide 60 to 80 percent of the water for 70 million people. Meteorological data show that snowpack in the last 30 years has been the lowest since record-keeping began a century ago, but the USGS study demonstrates that the recent decline is unusual over a 1,000-year time scale.