Torrential rains flooded roads, much-needed snow piled up on the mountains, and atmospheric rivers hit California for the first time.
On Wednesday, the storm first hit the San Francisco Bay Area, causing cable car service disruptions before concentrating energy in southern and eastern California. On Thursday, a downpour arrived in Southern California in time, disrupting the morning commute.
Bob Olavic, a forecaster for the National Weather Service, said an atmospheric river, a long band of water vapor that formed over the Pacific Ocean, fueled the storm that hit the Los Angeles and San Diego areas on Thursday.
Atmospheric rivers "usually precede a cold front across the Pacific Ocean," he said. "As they interact with the West Coast terrain, you'll often get heavy rains in the coastal mountains and inland mountains. ”
Flooding along the Pacific Coast Highway at Seal Beach, south of Los Angeles, on Thursday caused parts of the highway to close multiple times and a white van stuck at an intersection. After the rain stopped around noon, an employee swept water out of a downtown storefront, and onlookers avoided the puddle.
On Thursday, as heavy rain began in Santiago, Rubén Gomez cleaned up debris from the gutter in his parents' neighborhood, which had been hit by severe flooding during the earlier storm.
He piled sandbags around the house left over from the last flood. After the earlier storm, firefighters had to rescue his parents, both 82 years old, from their home when the water level of the storm reached 6 feet (2 meters) high. His father spent two days in the hospital with hypothermia, and his mother spent a week in the hospital after water got into her lungs.
"Every hole in the house, I plugged it with plastic and paper to make sure the water didn't rise so high again," he said. ”
They have no insurance and can only rely on donations from family, friends, and neighbors. He said he is still grateful because his parents survived last time and are now safely living in a home that is less prone to flooding.
But last winter, the storm became deadly. California has been hit by many arid atmospheric rivers that have caused widespread flooding, large waves hitting shoreline communities, and rare snowfall destroying buildings. More than 20 people died.
Weather forecasters say this week's "Pineapple Express" — so called "Pineapple Express" because it carries a long plume of water vapor across the Pacific Ocean and into the vicinity of Hawaii — will usher in a more powerful storm on Sunday.
The California Governor's Office of Emergency Services activated its operations center and deployed personnel and equipment in areas most affected by the weather.
Brian Ferguson, the office's deputy director for crisis communications, described the situation as "a significant threat to the safety of Californians." From the state's border with Oregon all the way south to San Diego, areas from the coast to the mountains could be affected in the next 10 to 14 days, he said.
"It's really a big area of California, and we're going to see threats in the coming week," Ferguson said. ”
South Los Angeles County was hit hard by flash floods on Thursday. Vehicles were flooded on low-lying sections of the highway, at least one underpass under the Long Beach railroad crossing was flooded, and a car was submerged.
In the southeast, a rapid rescue team rescued a man from the turbulent storm passage of Costa Mesa. The Orange County Fire Department posted on social ** that the man had been taken to the hospital and was in stable condition.
The Mammoth Mountain ski resort in Sierra Nevada received 12 to 14 inches (30 to 36 centimeters) of snow overnight. Earlier this week, California** reported well below normal levels of snow cover in the vital Sierra region. Typically, the Sierra snow cover provides about 30% of California's water resources. Heavy snowfall was also reported in the mountains east of Los Angeles.
The weather service office in Reno, Nevada, said the winter storm warning lasted until Friday morning and covered the Sierra Range, which runs nearly 300 miles (483 kilometers) north of Lake Tahoe to south of Yosemite National Park. In some areas, snowfall could reach 2 inches (5 centimeters) per hour and winds could reach 100 miles (160 kilometers) per hour, weather forecasters said.
Daniel Swain, a climate scientist at the University of California, Los Angeles, said the second storm, which is expected to move on Sunday, could be stronger.
Models suggest it may intensify as it approaches the California coast, Swain said in a briefing on Tuesday — a process known as bomb generation, in which a rotating low-pressure system rapidly deepens. This process is often referred to as a bomb whirlwind.
Swain said the situation could bring brief heavy rain and a major storm to the San Francisco Bay Area and other parts of Northern California.