The postponed deadline applies to payments as well as filing. But it's not for all of California. It depends on which storm you were affected by, and what county you live in. See the page at the link below on the IRS web site for more information. On that page, the "More Information" or "Detailed Information" link for the specific storm will lead you to the official IRS announcement with all the details.
https://www.irs.gov/newsroom/around-the-nation-california
