First, know the expected conditions. There are three levels of chain requirements in California:

Requirement 1 (R-1)

Chains are required on all vehicles except passenger vehicles and light-duty trucks under 6,000 pounds gross weight and equipped with snow tires on at least two drive wheels. Chains must be carried by vehicles using snow tires. All vehicles towing trailers must have chains on one drive axle. Trailers with brakes must have chains on at least one axle.

This is good news for most Subaru owners because mud and snow tires come standard on all new Subaru's except the BRZ, WRX, and STi models.

Requirement 2 (R-2)

Chains or traction devices are required on all vehicles except four-wheel/all-wheel drive vehicles with snow-tread tires on all four wheels. Note: four-wheel/all-wheel drive vehicles must carry traction devices in chain control areas.

This is good news for every Subaru built since 1997 with the exception of the BRZ. This is because the rest of the Subaru line-up has come with Subaru's Symmetrical All Wheel Drive standard. WRX and STi customers will want to check their tires to see if they have Mud and Snow tires, or if they have stock summer tires as it differed from model year to model year. Written on the side of your tires you will see M+S. This means mud plus snow tires.

Requirement 3 (R-3)

Chains or traction devices are required on all vehicles, no exceptions. R-1 and R-2 are the most common conditions. A highway will often be closed before the R-3 condition is imposed. Some areas may use variations of these designations.

Second, purchase your chains or cables before you head to your snowy destination. You will find recommendations in your Subaru's owner manual about which option is recommended for your particular year and model. Remember, even if you are not going to need to put them on, you will most likely need to show them to local authorities monitoring the roads.

Third, be safe and have fun.

For full details of requirements, always consult local authorities. Caltrans is an excellent source of information for local areas such as Highways to Wrightwood, Big Bear, Lake Arrowhead, Running Springs, and Crestline. Also excellent to check the conditions of the Cajon Pass if you are traveling to the High Desert Communities of Victorville, Apple Valley, Oak Hills, Phelan, Adelanto, or Barstow.