By Dale Kasler and Ryan Sabalow
May 1, 2017

The wettest winter in Northern California history ended the drought and produced an abundant Sierra Nevada snowpack.

Now it’s starting to melt, and quickly.

As state officials completed the final snowpack survey of the season Monday, forecasters predicted high river flows throughout spring into midsummer.

The federal government’s California Nevada River Forecast Center said the undammed Merced River, which flows through the Yosemite Valley, could rise above flood stage this week. The flooding could create “nuisance” impacts such as closing access roads or campgrounds in the national park, said the forecast center’s hydrologist Alan Haynes.

The forecast center said about 5 percent of the snowpack has melted in the past few days, as measured in “snow water equivalent,” and potential trouble spots abound. Many of them are in the southern San Joaquin Valley, where levees have been under strain for months.

“The thing we’re watching out for … is the southern Sierra, where we have full reservoirs and in some cases a huge snowpack,” said Frank Gehrke of the state Department of Water Resources, which oversees the snow survey.

Speaking to reporters following the snow survey off Highway 50, he said DWR’s Airborne Snow Observatory, a joint venture with NASA’s Jet Propulsion Laboratory, will run additional flights over the San Joaquin rivershed through spring and early summer “so we can track the melt precisely.”

In Sacramento, county officials warned boaters and other recreational users about high flows on the American River this spring. Already Monday afternoon, a raft with five people aboard capsized when it hit a pedestrian bridge on the American River near Sunrise Boulevard. Three rafters made it to shore but two were left clinging to the bridge pilings until rescuers reached them.

Kim Nava, spokeswoman for Sacramento County Regional Parks, urged residents to avoid swift waters – or wear a life vest if they insist on going into the rivers. “Even the strongest swimmer can be pulled under,” she said.

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