Cool temperatures last weekend slowed the rapid melting of the state's snowpack caused by this month's mostly balmy temperatures, a federal hydrologist reported this week.

Julie Koeberle, a snow hydrologist with the U.S. Department of Agriculture's Natural Resources Conservation Service in Portland, said the state had normal to above-normal snowpack levels as of April 1. But the warmer than usual temperatures sparked a snowmelt that was twice the normal rate for this time of year at numerous locations, she said.

April brought unseasonably warm weather, including a record-high temperature of 85 degrees on April 7, measured at Portland International Airport. Two weeks later, downtown Portland and the airport also saw record highs. By April 22, the amount of water stored in the snowpack, called the snow water equivalent, was well below the 1981-2010 average.

The Deschutes and Malheur regions of central and southeast Oregon measured 11 and 31 percent of normal, respectfully, on April 22. Other river basins came in between 51 to 83 percent of the median for this time of year.

"The good news is that last weekend's cold front has slowed down the snowmelt," Koeberle said. "If we can hold onto the snow that we have for a few more weeks or if we have a cool and wet May, then water supplies should still be on track for the summer.

At a measurement station at Mt. Hood's Timberline Lodge on Thursday, Koeberle measured 7.5 feet of snow depth, which is about 69 percent of average. That translates into a depth of nearly 4 feet of water, when it should be closer to 5 feet, she said.

However, don't hang up your skis just yet, she said.

"The ski areas did great this year and there is still plenty of snow left to play in ... Basically, this year has twice as much snow as last year on this date and the peak of the snow season was nearly three times that of last year," Koeberle said.

The conservation service will predict how much of that snow will melt and flow into a river or tributary later in the year for farmers, businesses, cities and others. Not enough snow could mean less drinking water or irrigation water for farmers and others.

"While snowmelt was early this year, reservoirs were able to capture the early runoff to improve their storage levels, which will help with water supplies," Koeberle said. "Once we have the snow survey results from around the state, we will be producing a more detailed water supply outlook report (possibly next week)."

-- Tony Hernandez

thernandez@oregonian.com

503-294-5928

@tonyhreports

The Associated Press contributed to this report.