A new storm system hit Northern California Friday with heavy rains, threatening millions of people Hazardous flood conditions As the snow from the previous storm melts. A flood advisory or warning was issued by the National Weather Service for San Francisco Bay, the Central Coast and areas around Sacramento and the San Joaquin Valley. Southern California received generally light rain.
The Atmospheric riversKnown as a “pineapple express” because it brought warm subtropical moisture across the Pacific from near Hawaii, nine atmospheric rivers melted the lower parts of the massive snowpack built up in the California mountains earlier in the winter and fueled the storm later in the Arctic blast. air
The snowpack at higher elevations is so massive that it was expected to absorb rain, but snowmelt was expected at elevations below 4,000 feet, forecasters said.
As the storm approached, Governor Gavin Newsom declared a state of emergency in 21 counties in addition to earlier declarations in 13 counties. President Biden on Friday approved Newsom’s request for an emergency declaration to authorize federal aid.
The California Department of Water Resources also activated its Flood Operations Center.
Reuters/Nathan Frandino
Early evacuation warnings were issued for various foothill and hill communities at risk of flooding and mudslides. An evacuation was ordered for a small number of Central Coast residents living under a levee near Oceano in San Luis Obispo County.
Flood control releases were underway or planned for some reservoirs that had been depleted during a three-year drought and filled by extraordinary winter rains and snow.
Releases were scheduled to begin Friday morning from Lake Oroville, the state’s second-largest reservoir, which collects water from the Feather River in the western foothills of the Sierra Nevada in the northern Sacramento Valley.
The lake level has risen about 178 feet since December 1. The stream flow is intended to ensure that there is scope for heavy water discharge.
State Water Projects Deputy Director Ted Craddock expressed confidence Thursday in the 1960s-era Oroville Dam, which had to evacuate thousands of people in 2017 after the main spillway collapsed and the emergency spillway began to erode.
“The spillway has been rebuilt to modern standards, and we are very confident that it will be able to handle the flow coming into Lake Oroville,” he said.
Forecasters warned that mountain travel could be difficult to impossible during the latest storm. At higher elevations, the storm was forecast to drop as much as 8 feet of snow over several days.
California’s Sierra Nevada snowpack, which provides about a third of the state’s water supply, is more than 180% of the April 1 average, when it is at its historical high.
Yet another atmospheric river is already in the forecast for early next week. State climatologist Michael Anderson said a third appears to be forming over the Pacific, and possibly a fourth.
California appeared to be “on its way to a fourth year of drought” before the early winter series of storms, Anderson said. “We’re in a very different situation now,” he said.
The Sierra and other mountain ranges have received so much snow that residents are still struggling to dig days after previous storms.
The storm reached blizzard status in late February in the San Bernardino Mountains east of Los Angeles. Roofs collapsed, cars were crushed and roads were blocked.
This week, firefighter-paramedics began delivering prescription drugs to residents who still can’t leave their homes, said Fire Capt. Steve Concialdi, a San Bernardino County emergency response spokesman.
On the far north coast, Humboldt County authorities organized an emergency response to feed starving cattle trapped by snow.
Cal Fire and the US Coast Guard launched helicopters Cattle dropping hay bales in remote mountain areas last weekend, and then the California National Guard was called in to expand the effort.
“We’ve had some unprecedented weather the last two weeks and we’ve had multiple reports of cattle dying because ranchers can’t get to their cows because of impassable roads,” said Sheriff William Honsall. “These cattle are an economic driver, they’re hungry and they’re calving now. So all of this needs some drastic measures.”