Officials are urging Bay Area residents to start preparing for flash flooding.
Along the Peninsula and South Bay, crews spent Tuesday preparing for more rain.
Many river beds and levees in the Bay Area are at risk of over flowing when big rains come from an expected El Niño this winter.
Crews in Palo Alto demonstrated how to cover and pack a slope. The Palo Alto Public Works Department also demonstrated how to properly sandbag a home to help prevent flooding.
"You want to lay the sandbags in an overlapping pattern like laying a brick wall," said John Hospitalier with the Palo Alto Public Works Department. "Fold it over like a burrito."
The California and San Jose Conservations Corps were training to use similar tactics on a levee along the Guadalupe River Bed.
The Santa Clara Valley Water District said if flash flooding is in the forecast, dozens of crews will be called out to prepare the high-risk areas.
"You can have a drought at the same time you have flooding," Hospitalier said. "We're trying to prepare for both."
The water district has several locations where people can stock up on free sandbacks. For more information, visit the Santa Clara Valley Water District's website.