Who do I pay?

Make checks payable to "UC Regents," and send them to the normal location:
Business Services - Insurance Section
University of California
171 University Hall
Berkeley, CA 94720-1104

If the Berkeley campus is shut down, payments should be sent to the Office of the President unless the disaster is affecting them as well:
UC Human Resources & Benefits
Health & Welfare Administration
PO Box 24570
Oakland, CA 94623-1570