Concern grows in Sierra, Valley as atmospheric river moves into central California
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FRESNO, Calif. – Forecasters with the National Weather Service are warning about potential risks to communities as an atmospheric river is set to make its way through central California starting Thursday.
An atmospheric river is a flowing column of water that produces rain and snow.
A series of those winter storms have already helped lift much of the San Joaquin Valley out of drought, delivering near-record snowfall totals across the Sierra Nevada.
But while the state was in need of water to counter its year-long drought, now, too much of it means communities are having to be alert yet again just two months after a previous series of storms nearly paralyzed some communities.
“This is not a garden variety storm. This is something that will bring impacts to daily life never experienced before,” Kristian Mattarochia, meteorologist with the National Weather Service office in Hanford, said this week during a briefing on the storms.
How much rain will fall?
Most of that rain is expected to fall between Thursday and Friday before lightening up and becoming more sporadic over the weekend.
The Valley could get up to 2 inches of heavy rain in some areas, while the foothills and mountains could get as much as 7 inches.
The rainstorm, predicted to be warmer, is bringing the possibility of melting snow below 5,000 feet elevation. Water releases were underway at Pine Flat Dam and Friant Dam to make room for extra water.
But a flood watch was also in effect in some places as forecasters predict water levels at rivers and streams may rise as a result of excess water.
Public safety officials warned residents along rivers and streams to have an evacuation plan and be ready to move to higher ground if necessary.
The Fresno County Sheriff’s Office issued evacuation warnings for the east side of the county and into the foothills where recent snow could melt and cause damage.
Evacuation warnings are also in place across Tulare and Madera counties.
“In the Valley, it’s probably going to be more of a nuisance. But if you’re close to any rivers or streams, it could become problematic,” Brian Ochs, a meteorologist with the National Weather Service in Hanford, said in a briefing earlier this week.
Snow impact in Sierra
Despite concerns of flooding and snowmelt, the snowpack at higher elevations is expected to remain intact. That may preserve much-needed water stored inside that can be useful in the spring and summer runoff periods for the Valley.
Forecasters say the snowpack is approaching seasonal records with about 50 inches of snow-water accumulated so far. Some communities have been covered in snow for days.
Throughout the week, public safety officials urged residents who may become stuck inside to stock up on household items and check their properties for areas susceptible to damage.
The Ash Mountain entrance to Sequoia National Park was set to close on Thursday, and closures may also be put in place at Kings Canyon National Park due to the heavy rain event expected.
Yosemite National Park also announced it will remain closed until at least March 12 as the storm passes through.
Eye on major rivers
Forecasters are also keeping an eye on several rivers and streams in the northern San Joaquin Valley.
As early as Friday, the San Joaquin River, Merced River and Tuolumne River could surpass their flood or monitor stages.
That’s the level where water can start to threaten lives and property.
In the City of Merced, forecasters are monitoring the flood stage for Bear Creek. It was just one of several areas in Merced County that flooded during storms in early January.
In January, Bear Creek reached a historic level of 26 feet, surpassing its flood stage level of 23 feet.