April streamflow forecasts show a decline in parts of every Western state and most basins, according to USDA’s Natural Resources Conservation Service water and climate experts.
NRCS hydrologists predict reduced spring and summer water supply for much of the West.
This month’s forecast is especially important because there probably won’t be significant snow accumulation after April 1, according to hydrologist Tom Perkins.
“April is usually the endgame. We’re not likely to make up this deficit. Snowpack is not good. Reservoir carryover is not good,” said Perkins.
Although other parts of the country got more snow, it didn’t have impact in the western mountains, he said.
“What fell in the West didn’t really amount to much,” Perkins said. “New Mexico, Nevada and Colorado are especially vulnerable because their reservoirs are at low levels due to sustained drought conditions.”
Water resource managers face difficult decisions due to this shortage, he said. Western states should prepare for potentially increased vulnerability to forest and rangeland fires and mandatory water restrictions. In addition, wildlife that depends on surface water is going to suffer.
There are a few exceptions to the dry forecasts. The North Cascades – including Washington and Western Oregon – and the headwaters of the Missouri and Columbia Rivers are near normal. “For the rest of the West,” Perkins said, “there is no silver lining. I think it’s going to be a long, hot, dry summer.”
According to NRCS Meteorologist Jan Curtis, most Western snowpacks peaked two to three weeks early this season and are now in decline. The best scenario would be for those snowpacks to melt slowly, providing a steady water supply through the spring and summer. This seems unlikely, given the above-average temperatures forecasted for the spring and summer.
“Although NRCS’ streamflow forecasts do not predict drought, they provide valuable information about future water supply in states where snowmelt accounts for the majority of seasonal runoff,” according to Perkins.
In addition to precipitation, streamflow in the West consists largely of accumulated mountain snow that melts and flows into streams as temperatures warm into spring and summer.
The April forecast is the fourth of six monthly forecasts issued each year between January and June by the national center. The forecast compares the current level of water content in snowpack in the 13 Western states with historical data to help the region’s farmers, ranchers, water managers, communities and other stakeholders make informed decisions about water use and future availability.
The snowfall, air temperature and numerous other factors taken from remote climate sites ultimately contribute to water supply. Now that Western snowpacks have peaked, the Governor’s Drought Task Force of each Western state will begin meeting to discuss drought preparations.
NRCS will continue to monitor levels across the Western states to provide the most up-to-date water supply information each month. The next two forecasts will measure rate of snowmelt and refine streamflow predictions.
“USDA streamflow forecasts play a vital role in the livelihood of many Americans,” said Jason Weller, NRCS acting chief. “With much of this region greatly affected by drought, our experts will continue to monitor snowpack data and ensure that NRCS is ready to help landowners plan and prepare for water supply conditions.”
Since 1935, NRCS has conducted snow surveys and issued regular water supply forecasts. NRCS installs, operates and maintains an extensive, automated system called Snow Telemetry, or SNOTEL, designed to collect snowpack and related climatic data in the Western United States and Alaska.
Other resources on drought include the U.S. Drought Monitor and U.S. Seasonal Drought Outlook map, which forecast drought conditions through March 31. For information on USDA’s drought efforts, visit www.usda.gov/drought. And to learn more about how NRCS is helping private landowners deal with drought, visit the NRCS site.