Cool weather, gradual runoff eases flooding potential

RENO, Nev. - A cool spring and some deft management of reservoir storage has tempered the potential for flooding this year when the huge Sierra snowpack finally gets around to doing some serious melting.

The threat of high water in streams and rivers along the Sierra has eased from high a month ago to moderate, National Weather Service hydrologist Gary Barbato said on Tuesday.

"Reservoirs in these basins are being managed to easily handle the snowmelt runoff which is forecast," he said.

As always, Barbato said all bets would be off if there is a prolonged spell of very warm weather or extensive heavy rain. The region is near the end of its traditional winter storm season.

Rivers with a moderate chance of some flooding are the Truckee, Carson, Walker and Humboldt, he said. The potential is low on the Owyhee and Snake rivers and nil in the south.

Barbato said the cool, wet April delayed the melt by several weeks, which will extend the runoff by several weeks, giving watermasters additional time to manipulate storage.

The long range outlook calls for below normal temperatures and above normal temperatures in the Sierra and most of northern and central Nevada through the end of the month.

Barbato said last month's storms added to an already heavy snowpack with the Lake Tahoe Basin at almost twice normal and most other watersheds running between 125 percent and 170 percent of their May 1 averages. The only exceptions were the Snake and Owyhee basins at around normal and the southern part of the state with next to nothing.

Reservoir storage remained substantial, ranging from 149 percent of normal in the Owyhee Basin to 116 percent in the Lower Humboldt Basin.

Most basins were in the 120-140 percent of average range, while control of their outflows kept them at 80-98 percent of capacity, Barbato said.

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