Lake Powell, which straddles Utah and Arizona, is expected to get 47 percent of its average inflow because of scant snow in the mountains that feed the Colorado River, said Greg Smith, a hydrologist with the Colorado Basin River Forecast Center, part of the National Oceanic and Atmospheric Administration.
It was the seventh-worst forecast for Lake Powell in 54 years.
Powell, along with Lake Mead on the Nevada-Arizona border, helps ensure the Colorado River system has enough water to get through dry years.
Normal allotment threatened Lackluster runoff into Lake Powell this spring is not likely to have an immediate impact on water users because most reservoirs upriver from Powell filled up after last winter’s healthy snowfall, said Marlon Duke, a spokesman for the U.S. Bureau of Reclamation, which manages Powell, Mead and other reservoirs.
Along the Green River, a Colorado River tributary in Wyoming, the snowpack is 110 percent of average.
Along the San Juan River in southwestern Colorado and northwestern New Mexico, it’s 32 percent of average.
One reason is a strong winter weather pattern steering big storms away from the Southwestern United States and sending them north, said Russ Schumacher, Colorado’s state climatologist and an associate professor of atmospheric science at Colorado State University.
Another reason is exceptionally warm temperatures across much of the Southwest, he said.
Lake Powell, the second-largest, is at 56 percent.
Some climate scientists say global warming is already shrinking the river.