May Drought Update: Snowpack, Streamflow and Water Storage at Low Levels and Expected to Decrease

According to researchers at the Colorado Climate Center at Colorado State University, the state’s snowpack, streamflow and reservoir storage continue to decrease while the statewide fire danger is increasing.

"Colorado’s 2000-01 low winter snowfall and precipitation, combined with abundant sunny skies which promoted snowmelt, sent the state’s snowpack percentages into a downward spiral and will result in decreases in expected streamflow," said state climatologist and professor of atmospheric sciences Roger Pielke Sr. "Lower levels of water in reservoirs this year only add to supply concerns."

The Colorado Division of Water Resources reports that in early May the state’s snowpack was only 19 percent of average. As a result of the dry conditions, by mid month more than 440 fires had burned approximately 23,000 acres in Colorado this year according to the Rocky Mountain Coordinating Center of the National Interagency Fire Center.

April marked the eighth consecutive month of below-average snowfall and precipitation for Colorado leaving the statewide snowpack on May 1 at a record low. The lowest snowpack percentages continue to be measured across southern Colorado, with the Rio Grande and combined San Juan, Animas, Dolores and San Miguel basins reporting only 6 percent of average. The North Platte basin at 44 percent of average has the highest snowpack in the state. Snowpack melt across Colorado has been progressing six to eight weeks earlier than normal, however, the state’s recent cooler weather has slowed the melting to some extent.

According to the Colorado Drought Task Force, statewide streamflow forecasts include much below average (50 percent to 70 percent of normal) for a small portion of the South Platte and Colorado river basins, and extremely below average (25 percent to 50 percent of normal) for the remainder of the South Platte and Colorado basins as well as the Yampa river basin. In southern Colorado, forecasts include a combination of extremely below average and exceptionally below average streamflow (0 to 25 percent of normal) for the Gunnison, Dolores, Rio Grande and Arkansas basins.

The state’s Colorado Drought Watch newsletter reports that reservoir storage across Colorado was 86 percent of average at the beginning of May. With increased summertime water demands, along with low inflows, reservoir storage is expected to be severely reduced throughout the upcoming months.

Livestock forage and irrigation water may be further threatened if current dry conditions continue. For more information about drought-related agricultural information, visit the Web at

The Colorado Drought Task Force, of which Pielke is a member, will meet again on May 23 in Denver to discuss the state’s drought situation. The task force is charged with overseeing Colorado’s drought plan and will discuss current water availability status, short and long term forecasts, current and anticipated drought impacts as well as preparedness activities.

The Colorado Climate Center, housed in Colorado State University’s Department of Atmospheric Science, provides information and expertise on weather and climate patterns for the state of Colorado. Pielke and research associate Nolan Doesken issue mid-month Colorado drought advisories throughout the spring and summer in conjunction with the center’s new Web site at that provides access to current drought data.

The site includes a special drought section with links to monthly Colorado Drought Watch newsletters, Colorado Drought Task Force reports and meeting minutes, water conservation and drought planning information, daily updated snowpack data, water supply and precipitation reports, and streamflow forecasts. The site additionally offers a variety of information regarding all aspects of Colorado’s climate and weather.