If you're unfamiliar with snow chains or cables or know them by a different name, they're devices fitted to a vehicle's drive tires to add traction when driving through snow and ice. They are usually purchased to match the tire size (diameter and tread width).
From November 1 to April 1 in California, all vehicles are supposed to carry tire chains (or cables) when they enter a chain control area, even if it isn't snowing at the moment.
Consequences of not having them in those areas could include fines, charges for damages from an accident and towing fees if a law enforcement officer stops you and decides the safest thing to do is to have your vehicle towed out of the snow area.
If you're a visitor, it can all sound pretty daunting, and you may wonder how you'll be able to see Yosemite National Park or other parts of California if you're planning a visit in winter.
If snow could be predicted with accuracy, it would be easy to know what to do, but weather can change quickly in the mountains. A drive that starts out on a sunny afternoon in San Francisco could take you into a situation where you'd not only need chains, but you'd need to put them on in a hurry.
California Snow Chain Requirement Levels
When it's snowing, these are the levels of snow chain requirements (quoting the Department of Transportation). You'll see them listed on signs like the one above.
Requirement One (R1): Chains, traction devices or snow tires are required on the drive axle of all vehicles except four wheel/ all wheel drive vehicles.
Requirement Two (R2): 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.)
Requirement Three (R3): Chains or traction devices are required on all vehicles, no exceptions.
What Are the Chances of Snow?
That's hard to say. In some years, it might snow very little and in others, the snow season starts early or drags on into spring. In general, it could snow as early as November, but in most years the Sierra ski resorts have to make most of their snow just to open by Thanksgiving, which is near the end of the month. By April, snow season is usually over.
Snow Chains and Yosemite National Park
Conditions dictate when chains are required at Yosemite, which makes it hard to know when you'll need them. The Yosemite website strongly recommends having chains with you from November through March, but they could be needed as early as September or as late as May.
Park regulations require that you MUST carry chains when driving in designated chain control areas, marked by a sign that says, "CHAINS REQUIRED" - even if you are driving a four-wheel-drive vehicle.
Unless it starts to snow, no one is likely to stop you and search your vehicle to see if you have chains with you. To get up-to-the-minute road conditions in Yosemite, call 209-372-0200.
During a snowstorm, Yosemite National Park rangers may close the roads to all motorists who don't have chains on their tires. And in the rare instance that you got in without chains and snow starts when you didn't expect it, you might get a traffic ticket, and/or your vehicle could be towed out of the snow area at your expense.
Yosemite Valley is at a lower elevation than the mountain passes, and if you take CA Hwy 140 through Mariposa, you might not encounter snow even if it's falling at higher elevations.
Another way to get into Yosemite when it's snowing and you don't have chains is to park your car at a YARTS (Yosemite Area Rapid Transit) bus stop on CA Hwy 140 outside the chain control area and take the bus into and out of Yosemite (fee required). Check the routes and stops at the YARTS website.
Snow Chains and Rental Cars
Few if any car rental companies make snow chains available to renters, but you might find them for rent in Reno, Nevada, which serves the Lake Tahoe ski area. Some car rental companies ban the use of chains or allow them but hold you responsible for any damage they cause, so you will need to check with yours to be sure.
To find out if you have snow tires on your rental, look on the wall of the tire for the letters MS, M/S, M+S or the words MUD AND SNOW - or an icon of a mountain with a snowflake. You may be able to drive without chains in R-1 and R-1 conditions if you have them.
You could buy chains for your rental at an auto parts store. A set will cost $40 or more. However, most shops do not accept returns (even if they're unused) unless you clearly bought the wrong size.
You can rent chains in some locations. NAPA Auto Parts at 4907 Joe Howard Street in Mariposa rents or sells them - and so do some of the gas stations in town. You may also find them in Coarsegold and Oakhurst. If you buy or rent, try to get them to show you how to put them on or try it yourself instead of depending on remembering hasty verbal instructions.
Chain Installers on the Highways
If you have chains but don't know how to use them, keep some cash with you if you travel in areas where they might be needed.
On the busier highways, chain installers (who are called "chain monkeys") spring up during a storm like mushrooms after a big rain. They charge to put your chains on for you, and again to take them off. Expect to pay $50 or more if you pay for both services.
Unless you know what you're doing, most people say it's worth the cost to avoid struggling in freezing weather. Some of the installers also sell chains. CalTrans issues them permits, they have to pass a test that involves untangling a set of chains and putting them on a car in less than five minutes. And they will be wearing a badge.
Visiting California in Winter
If you're reading about snow chain requirements, I'm going to take a wild guess that you're thinking about visiting California in the winter. These resources may help: