Atmospheric Rivers (AR) are narrow bands of concentrated moisture in the atmosphere, essentially rivers in the sky that transport vast amounts of water vapor from tropical regions to the West Coast. They are critical to California's water supply, providing 30-50% of our annual precipitation in just a few storms each year. On average, 24 atmospheric rivers make landfall on the West Coast each winter season. We are expecting a Category 2–3 Atmospheric River from Wednesday through Saturday, bringing moderate (0.5 - 1.5 inches) rainfall to San Mateo County.
While widespread flooding is not anticipated, there is potential for nuisance flooding in urban and poor drainage areas, with minor creek and stream rises.
For those worried about possible flooding, free sandbags are available in Holbrook Palmer Park near the tennis courts.
For more resources, visit the Town's Storm Preparedness Webpage. Linked HERE is an update from the San Mateo County Department of Emergency Services.