These graphs show the crashes where the California Highway Patrol responded, between March 1, 2020 into April, 2020. The top graph shows the number per day of all crashes and number of collisions/day where an injury/fatality occured. The bottom graph shows all crashes by area. In both graphs, the spike in crashes between 4/5 and 4/10, including injury/fatality crashes, was possibly due to heavy rains in the Los Angeles and San Diego areas.

About the data

On April 6, 2020, Los Angeles experienced record rainfall.
https://www.dailynews.com/2020/04/06/rainfall-total-in-downtown-los-angeles-tops-a-record-set-in-1958/

On April 10, 2020, Heavy rains in San Diego and Oceanside.
https://www.kpbs.org/news/2020/apr/10/heavy-rain-expected-thunderstorms-possible-in-san/