San Joaquin County in California is likely to experience rain showers and possible thunderstorms this week, followed by a warm storm system that could lead to more flooding over the weekend.
The National Weather Service in Sacramento has issued a high chance of rainfall in the valley from an existing storm system until Wednesday morning, and a warmer storm system is predicted to bring heavier rain and potential roadway flooding from Thursday evening.
Director of Emergency Operations Tiffany Heyer has cautioned that the warmer system could bring one to two inches of rain to San Joaquin County, and possibly three inches in isolated areas. With the ongoing wet weather patterns, low-lying areas that see flooding from normal storms are expected to experience the same issue again. While the county is monitoring for river rises, snowmelt, and reservoirs, it faces normal drainage type issues.
In late February, a rare cold storm brought widespread low-elevation snow to California and saturated the Sierras, which resulted in 177% of average snowpack at the Department of Water Resources' Phillips Station by March 3, with 116.5 inches of snow. However, the incoming warmer atmospheric river could rapidly increase the snow level from 3,000 feet to 6,000-8,000 feet, leading to flooding trouble in California from rain melting snow too quickly and overburdening the state’s rivers and water systems.
Heyer noted that the county is working to ensure the capacity in river systems can accommodate both rain and potential snowmelt. But, it is still too early to know the exact impact of the storm, and there could be a few changes before the system hits.
According to climate scientist Daniel Swain, who works at the University of California, Los Angeles, there will be a flood risk with the upcoming warm storm. However, he expressed concern about the growing risk of additional warm atmospheric rivers moving into mid-March, which could lead to significant problems.
The county is focused on preparing for the potential impacts of the weather, and Heyer urged people to clean their gutters and waterways to the best of their ability. She also advised residents to start preparing for evacuation in case of an emergency, as it is better to be prepared and ready to go than to be caught off guard when the system changes and stalls or something happens where there is a need to evacuate, and no one has been prepared. More information on local winter storms can be found at Sjready.org.
