Southern California Braces for Heavy Rainfall and Flooding as Atmospheric Rivers Hit
Southern California is preparing for heavy rainfall and potential flooding as two atmospheric rivers are set to hit the region. The first storm is expected to strike on Thursday, bringing gusty winds and heavy rainfall that could lead to flooding in some areas. More than 20 million people across California, including cities such as San Diego, Sacramento, San Francisco, San Jose, and Oakland, are under flood alerts. The threat of flooding will last into Friday morning for central and Southern California.
This is just the beginning, as another atmospheric river, likely stronger than the first, is expected to move across the region starting on Sunday. Rainy conditions are expected to continue well into next month as a more typical El Niño pattern kicks into gear. El Niño is a natural phenomenon in the tropical Pacific that influences weather around the globe. It causes changes in the jet stream that can point storms directly at California and allows storms to tap into an extra-potent supply of moisture from the tropics called an atmospheric river.
The first storm has already hit Northern California, bringing steady rain to the area. As it moves south, central California will also experience rainfall through Thursday. The heaviest rainfall is expected in areas north of San Luis Obispo to the California-Oregon state line, including the Bay Area. By Thursday morning, Southern California will start experiencing steady rainfall and periods of stronger winds. Rainfall of 1 to 4 inches is possible in the southern part of the state, with rates that could exceed 1 inch per hour.
A Level 2 risk of excessive rainfall is in place for Southern California as the rain moves south. Roads and low-lying areas are at the highest risk for flooding, and rises on some waterways are also possible. Flood watches are expected to remain in effect through Thursday evening for central California, with rainfall totals of 1 to 3 inches possible and isolated totals exceeding 4 inches.
In addition to heavy rainfall, the western half of California could see a few thunderstorms that may produce bursts of heavier rain. This comes after a series of torrential thunderstorms wreaked havoc on San Diego last week. To respond to potential impacts, California officials are readying hundreds of crew members from multiple agencies to provide rescue assistance. The state’s Office of Emergency Services has prepared swift water personnel and equipment in 12 counties, with more than 400 personnel prepositioned across 16 California counties.
While Southern California braces for heavy rainfall, officials farther north are preparing for wintery weather conditions. More snow is expected to accumulate at lower elevations across parts of Northern California and the Sierra Nevada on Thursday. Winter storm warnings remain in effect for the Sierra Nevada, where up to 4 feet of snow are possible in some higher elevations. This snow is welcomed for California’s snowpack, which has been affected by warmth and rain instead of snow. The current snowpack is only 52% of average for this time of year, according to the latest survey conducted by the state’s Department of Water Resources.
Looking ahead, Friday will bring showery weather that is expected to linger over much of California. Then, on Sunday, another more potent atmospheric river-fueled storm is set to hit Southern California. Meteorologists warn that this storm could potentially be the “largest storm of the season.” Forecast models show a more widespread and prolonged flood threat, especially for Southern California. Temperatures are also likely to start out much cooler with this storm, with more snow possible down to mountain pass levels or even lower elevations.
As Southern California prepares for the heavy rainfall and potential flooding, residents are urged to stay informed about the weather conditions and heed any evacuation orders or warnings issued by local authorities. Stay safe and be prepared for the impact of these powerful storms.
