Record amount of snow pack melting quickly into Merced River, officials say

Northern California saw one of the wettest winters on record, and all that precipitation caused snow in the Sierra Nevada to build up quickly. That will mean rapid melting now that spring is here.

Warming temperatures are causing melting snow to flow into the Merced River, but Merced Irrigation District officials say there will be no flooding impact on local lakes and dams.

“In May, we start getting the peak snow melt season,” said Jim Dudley, meteorologist for the National Weather Service in Hanford. “How warm temperatures are during the month will determine how high the flow is on the rivers.”

On Wednesday and Thursday, temperatures in Merced are forecast to hit around 90 degrees, Dudley said. Tuesday’s temperatures will reach just below 90 degrees.

The water flows coming from Yosemite won’t impact the New Exchequer Dam that’s on the Merced River, said Mike Jensen, spokesman for the Merced Irrigation District. Lake McClure, which is 66 percent full as of Tuesday, also is in the clear.

“Merced Irrigation District has been planning for this runoff and preparing all winter by making space available in Lake McClure,” Jensen said in an email to the Sun-Star. “Over the next 10 days, the reservoir will increase to about 71 percent of its capacity.”

He added: “The higher lake levels will be welcomed by recreationists and the flows should have no impact below Exchequer Dam.”

High water levels in Yosemite Valley prompted park officials to close the Merced River for rafting and swimming for at least the next several weeks, park spokesman Scott Gediman said. Levels are expected to be high for the next week and it’s possible the river will go above the flood stage, he said.

“In Yosemite Valley, we have a lot of creeks and streams that flow into the Merced River,” Gediman said. “So, it’s just a question of asking people to be very careful of it.”

In some areas, the Merced River can seem “calm and placid,” Gediman added, but it’s important to know the water can be “deceiving.”

“We ask people to enjoy the water, but enjoy it from a distance,” he said.

Two of the biggest dangers this time of year are people contracting hypothermia because of the cold water and being swept away by the current, Dudley said.

“People want to go out to the local river or stream and the water is cold and can be swift flowing,” he said.

By the end of the week, temperatures are expected to cool, Dudley said. Friday’s highest temperature will reach 79 degrees and drop to 70 degrees on Saturday.

This story was originally published May 1, 2017 at 4:53 PM with the headline "Record amount of snow pack melting quickly into Merced River, officials say."