The strongest storm of the year will be in the week, forecasters warn of potential widespread road flooding and landslides across the region – especially in areas recently burned in the devastating Los Angeles County fires .
The rainfall will not have brought much beneficial rainfall to Southern California as it has been in the relatively small storm that has been to Southern California in the past two weeks. Forecasters recommend avoiding travel if possible.
“Thursday was not a great day on the journey,” said Ryan Kittell, a meteorologist at Oxnard National Weather Service. “If nothing else, [expect] Many smooth roads, many traffic accidents. There will be some road flooding. Not all areas… but certainly more than we see this winter.
“If you have the option to cancel, please delay [or] Rescheduling any kind of event (especially Thursday) is a good idea,” Kittle said.
Those living in areas with recently burnt down should plan to leave their homes before the storm, or, if they choose to stay at home, work hard and stay away from the road. The National Weather Service warned that “potentially life-threatening and destructive flooding and debris flows” and said the next few days could end up being the wettest storm throughout the winter.
Even if there is no large amount of debris flow, the roads can be muddy, and “there may be a lot of road closures among those with burn scars.” Debris flow is a kind of landslide, and water flows rapidly downhill – moving to 35 mph, not only picking up mud, but also rocks, branches, and sometimes huge boulders and cars.
Heavy rains may come on Wednesday, but the biggest risk of flooding and debris flow is Thursday. Downtown Los Angeles may see 2.17 inches of rain Wednesday to Friday.
The last time it rained about a year ago, when 8.51 inches hit Los Angeles over a three-day period, in Beverly Glen, Studio City, Tarzana, Baldwin Hills and Hacienda Heights triggered destructive mudflows.
It is expected to take effect at most of the mountainous foothills in the Sierra foothills east of Southern California and the San Joaquin Valley.
The storm is passing through the atmospheric river. Atmospheric river storms are long water vapor that can be poured from the Pacific Ocean into California. They hold too much water, and they are said to be like rivers in the sky. Only a few atmospheric river activities can drive California from one-third to half of its annual precipitation.
Much of Southern California and the Sierra Foothills along the San Joaquin Valley are expected to be under flood surveillance or flooding later this week.
(National Meteorological Administration)
Here’s what you need to know:
timing
Showers may start on Wednesday – but they will be light if they achieve.
Santa Barbara and San Luis Obispo counties are expected to take place on Thursday, as well as Los Angeles and Ventura counties from Thursday afternoon to Friday morning.
Heavier rainfall could reach Los Angeles County around 2 or 3 p.m. Thursday and then build until late at night, Kittle said.
“The morning can be dry or wet, but it will certainly rise throughout the afternoon,” he said.
The highest rainfall is expected to be seen in Los Angeles and Ventura counties, Thursday to Friday morning, on Thursday, Santa Barbara and San Luis Obispo counties.
(National Meteorological Administration)
In the Inland Empire and San Diego and Orange County, the biggest rainfall is expected Thursday afternoon and evening. Adam Roser, a meteorologist with the Meteorological Services San Diego office, said the storm was not expected to be effective there, but “it remains a major event this winter.”
Thursday will also be the strongest day in the storm in the San Francisco Bay Area and Sierra Nevada.
Shallow landslides may be possible, with large river flooding and localized flash flooding, expected in the Bay Area, urban and stream flooding, as well as in Santa Cruz and Monterey counties, according to Monterey’s Meteorological Services Office.
Rainfall
Forecasters expect rainfall in most areas of Los Angeles, Ventura and Santa Barbara counties, with forecasts of 3 to 6 inches in the mountains. More rainfall is expected to be seen in San Luis Obispo County: 3 to 5 inches and 5 to 10 inches in the mountains.
Lancaster may get 1.14 inches of rain; Redondo Beach, 2.04 inches; Downtown Los Angeles and Long Beach, 2.17 inches; Thousand Oaks, 2.19 inches; Canoga Park, 2.32 inches; Santa Clarita, 2.38 inches ; Covina, 3.07 inches; Santa Barbara, 3.25 inches; San Luis Obispo, 3.75 inches; and Cumbria, 3.97 inches.
(National Meteorological Administration)
The riverfront can reach up to a tenth of an inch in the rain expected on Wednesday. Anaheim and Irvine, up to two-fifths of an inch; Ontario, Lake Elsino and Lake San Clemente, up to half an inch; and San Diego, Escondido and Oceanside, up to one tenth of an inch.
Predicted rainfall maps for San Diego and Orange County and the Inland Empire on Wednesday.
(National Meteorological Administration)
It is not particularly rare for downtown Los Angeles to have about 2 inches of rain in a storm, but such storms can cause problems including local flooding.
“That’s how it tends to be in Southern California: We don’t have that many storms. We tend to have more “rain, downpour” here, says meteorologist Rose Schoenfeld.
For heavy rains expected from Thursday to Friday, San Diego and Escondido may rain 1 to 1.5 inches. Anaheim, Irvine, San Clemente, Riverside, Lake Elsinore and Oceanside, 1.5 to 2 inches; and San Bernardino, Ontario and Temecula, 2 to 2.5 inches.
While it’s not 1.5 to 2 inches of rain in a storm for places like Orange County, Roser said: “It must have happened in a winter storm like this.”
Total rainwater forecasts for Orange and San Diego County and the Inland Empire Thursday and Friday.
(National Meteorological Administration)
North, San Jose, Concord and Livermore may get 1.5 to 2 inches of rain; San Francisco, Napa, Monterey and Santa Rosa, 2 to 3 inches; Big Sur, 4 to 6 inch.
Rain in Bakersfield may range from 0.73 to 1.67 inches; Fresno, 0.82 to 1.78 inches; and Merced, 0.6 to 1.36 inches. The Sacramento Valley has a 50% to 80% chance of receiving 1 inch or more rain over a two-day period. The chances of rainfall in the adjacent Sierra Foothills and Shasta County are 50% to 85%.
Burning alert area
Southern California suffered the driest start of the rainy season in recorded history and one of the most devastating fire seasons ever. As a result, given that vegetation has been burned and the soil can no longer be held in place, there are now many burned areas with high alert for potential landslides.
Experts say once rains are raining at a rate of half an inch per hour, the risk of mud and debris rising from burning hillsides increases. This could happen this week, as rainfall rates in Los Angeles, Ventura, Santa Barbara and San Luis Obispo counties are expected to peak between half an inch and 1 inch per hour.
“We do expect a lot of enhanced precipitation cells,” Kitel said.
“These cells could end up being very much like thunderstorms,” Kitel said, “a short, heavy downpour, and maybe even a strong, stormy wind.” ”
Animated infographics show debris flow
Kittell said there will be “the risk of massive flooding, as well as the recent flow of burn scars and debris. ”
The recent burn scars will take effect, which may start from Thursday to Friday morning at noon.
The most notable are the Eaton fire scars in the Altadena area, the Palisades and Franklin fire scars in the Pacific Palisades and Malibu, and the Bridge fire scars in the San Gabriel Mountains west and southwest of Wrightwood.
The nearest Burns area in Los Angeles and Ventura County will take effect later this week.
(National Meteorological Administration)
Kittle said residents who returned to their homes in the burn area may want to consider a temporary relocation.
“If you have the option to go somewhere else, that’s great, especially on Thursday,” the meteorologist said.
Otherwise, he advises avoid leaving and try not to drive in areas that were recently burned down on Thursday.
In San Diego and Orange County and the Inland Empire, at high altitudes, rainfall may drop at a rate of half an hour.
Flood risk
Road flooding is expected, including on highways, as well as on Onramps and offramps. Due to flooding, several roads may be closed and streams and rivers will expand and strengthen. If people are flooded by water from rivers and other waterways, quick water rescue may be needed.
In Santa Barbara and San Luis Obispo counties, the risk of small flooding is moderate. The highest risk in San Luis Obispo County is the other community mountains on the slopes of Cumbria and other neighborhoods, which are towering mountains.
Strong wind
This winter, the storm is also expected to bring the strongest winds in the storm, with peak gusts of 40 to 60 mph on the mountains, deserts and the central coast and 20 to 40 mph elsewhere.
23 mph peak gusts can be seen in downtown Los Angeles and Santa Barbara; Long Beach, 26 mph; Redondo Beach, 30 mph; Santa Clarita and Canoga Park, 32 mph HOUR; Thousand Oaks, 35 mph; Pyramid Lake, 37 mph; San Luis Obispo, 44 mph; and Lancaster (52 mph).
Strong winds can lower trees and power cords, causing electrical disruptions.
Winds are expected to be found in the east of Los Angeles International Airport, which could change flight patterns and cause delays.
Kittle said the risk of water spray and tornadoes is also low. “I wouldn’t be surprised if we received a report or two of funnel clouds, or even a report from Watersept,” he said.
(National Meteorological Administration)
After the storm leaves
Sometime Friday, the storm may move out of the area – launching a spell that might be somewhat dry. There are no strong storms in Southern California for much of next week.
“Of course, by Saturday, we’ll be dry,” Kittle said. Temperatures are expected to rise next week.
