Flood watch issued for Bay Area as atmospheric river storm approaches

On January 31, 2025, the National Weather Service in the United States issued a flood watch for the entire Bay Area, which encompasses nine counties including Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Santa Clara, Santa Cruz, and Sonoma. This advisory came as a strong atmospheric river storm moved into Northern and Central California, signaling the return of much-needed wet weather after a notably dry January. The flood watch is effective from noon on February 1 until 10 p.m. on February 3, with predictions of excessive rainfall across the region. The weather service forecasts that excessive rainfall could lead to flooding in low-lying areas, prompting residents to prepare for potential flooding events. Rainfall is expected to range from 1 to 3 inches, with localized areas in higher elevations potentially receiving up to 5 inches by Sunday afternoon. Residents are urged to remain vigilant and monitor ongoing weather forecasts, especially those living in flood-prone areas. Key preparation measures recommended include clearing storm drains of leaves and debris, and ensuring that umbrellas and rain gear are readily available. The first significant rainfall of this year began arriving early Friday, spreading from the North Bay southward throughout the day. Early estimates suggested that the North Bay could receive between 0.5 to 1.5 inches by the end of Friday, while areas further south in the Bay Area could see up to half an inch. Saturday was expected to bring sustained rain, with peak intensity anticipated in the morning and early afternoon hours. Following Saturday's heavier showers, rainfall is projected to lessen in intensity, particularly in the North Bay on Sunday. The storm is significant since it marks the first notable weather system to reach the Bay Area in several weeks. The last measurable rainfall in the region occurred on January 3, 2025. The current atmospheric river is likely to persist into early the following week, with forecasts indicating another potential round of heavy rainfall on February 5 and 6. Besides the risk of flooding, windy conditions accompanying the heavy rains may also lead to downed trees as soil becomes saturated. Public safety authorities are encouraging drivers to exercise caution during severe weather, particularly warning against driving through flooded roadways.