The scientists, and sanitation and street maintenance workers will visit the areas Friday, Villaraigosa said, warning of possible lightning, hail and water spouts in the latest in a series of storms, CNN reported.
"While the worst of the last few storms is behind us, there still is a significant threat from thundershowers that are forming off the coast," Villaraigosa said during a news conference Thursday night.
State Attorney General Jerry Brown, who is in charge of the state in Gov. Arnold Schwarzenegger's absence, declared a state of emergency Thursday in several California counties hit by a series of Pacific storms this week. The declaration included Los Angeles, Orange, Riverside, San Francisco and Siskiyou counties. Schwarzenegger is in Washington.
Mandatory evacuation orders were issued for Acton, La Crescenta and La Canada Flintridge, at risk for mudslides after wildfires burned away vegetation last year.
Residents ignoring evacuation orders were taking a risk, safety officials said.
"Please understand that if you have a need for paramedics, firefighters or other first-responders, we may not be able to get to you due to mud and debris flows preventing access," Los Angeles County Fire Department Deputy Chief Mike Metro said.
California Emergency Management Agency reported two weather-related deaths.
Rainfall of between 1-4 inches was expected across parts of coastal California into Friday, with up to 7 inches of rain possible in isolated areas, forecasters said.
Heavy snowfall was predicted for higher elevations in the Sierra Nevada, and parts of Utah, Colorado and Arizona, CNN said. More than 73 inches of snow had fallen in California's Chagoopa Plateau since Sunday, and more than 35 inches of snow blanketed parts of Arizona.