Highway Patrol Incident Report (choose Yreka)
https://cwwp2.dot.ca.gov/vm/iframemap.htm
R-1 modified: Chains required on all single axle drive trucks and vehicles towing trailers.
R-1: All vehicles except autos and pickup trucks with 4 snow tires.
R-2: All vehicles except 4WDs with snow tires.
R-3: All vehicles.