A powerful atmospheric river is currently bringing heavy snowfall to high elevations and strong winds and heavy rainfall across a significant portion of California.
More than 20 million people are under flood alerts as the storms pose threats of flash flooding in cities such as Los Angeles, San Diego, Sacramento, San Francisco, San Jose, and Oakland. The flood risk is expected to persist into Friday morning for central and Southern California.
After Thursday’s storm passes, another atmospheric river, potentially stronger, is forecasted to impact the region starting Sunday. Rainy conditions are anticipated to persist throughout February as a more typical El Niño pattern influences the weather.
El Niño, a natural phenomenon in the tropical Pacific, alters the jet stream, directing storms towards California. These storms can tap into an intense supply of moisture from the tropics known as an atmospheric river.
The first of the two atmospheric river storms hit Northern California on Wednesday, moving southward through central California overnight. Southern California is experiencing steady rainfall and strong winds, with much cooler temperatures prevailing across the state.
Rainfall estimates range from 1 to 4 inches in the southern part of the state, with rates exceeding 1 inch per hour. Southern California faces a Level 2 out of 4 risk of excessive rainfall, raising concerns of flooding in low-lying areas and along roadways.
Flood watches remain in effect for central California through Thursday night, with an additional inch of rain anticipated. Western California may experience thunderstorms, following last week’s torrential thunderstorms in San Diego.
Officials in flood-prone areas, including San Diego, are advising residents to prepare for potential evacuations. Emergency services are on standby across multiple California counties to respond to flood-related emergencies.
In northern regions, more snowfall is expected, particularly in the Sierra Nevada, where up to 4 feet of snow could accumulate. The snow is crucial for California’s snowpack, which currently stands at 52% of average.
Looking ahead, Friday will bring showery weather statewide, with another atmospheric river storm forecasted to impact Southern California starting Sunday. This storm could be the most significant of the season, potentially bringing prolonged periods of heavy rain and snow across the region. Residents are advised to stay informed and prepare for challenging weather conditions in the days ahead.