What you need to know about the atmospheric river poised to slam Bay Area FacebookTwitterEmail A woman wearing a mask walks with an umbrella in the Richmond District of San Francisco, California during a steady rainfall. The first significant rainstorm of the season hit the San Francisco Bay Area on Nov. 17, 2020.Douglas Zimmerman/SFGATE The biggest storm of the rainy season so far is forecast to wallop the San Francisco Bay Area Tuesday through Thursday, delivering a heavy dose of soaking rain and high winds that could wreak havoc throughout the region, flooding roadways, triggering debris flows in wildfire burn scars and knocking out power.