Winter driving is a skill and not just in the driver’s seat. Knowing when you should drive, when you should wait, and what to toss in the car. Unfortunately for people visiting Mammoth (or any snowy mountain area) this just isn’t something they need to deal with all the time so those skills can be a bit rusty.
Step one: understand California chain control rules.
There are three levels of chain control, and you can see these by checking the highway status from Caltrans. Here’s the 395 (major Eastern Sierra highway) and the 203 (connects the 395 to Mammoth’s Main Lodge). (Edit, November 2019: Caltrans has updated its site. You can use this). Mid-storm, you’ll want to keep checking this every ~30 minutes because the chain control restrictions and road closures shift with the conditions.
- R1 – Unless you have snow tires (with M+S stamped on the sidewall), you need to have chains or cables on one of your axles.
- R2 – Unless you have AWD/4WD with snow tires, you need to have chains or cables on one of your axles.
- R3 – Never really seen, and honestly you should turn back if you see this. Typically roads are closed past R2. I wouldn’t personally go out in R3 unless I had sufficient equipment to bail on my vehicle and head out on foot, or wait out the entirety of the storm in my vehicle (fuel, heat, food, water, etc). R3 is really dangerous.
Cables count as chains, and modern cables work great. Practice putting them on at home and if you don’t have 4WD/AWD make sure you put them on the axle that the motor actually spins. If you have a 2WD car or truck make sure you know whether it’s front wheel or rear wheel drive and that’s where your chains/cables go. If you have 4WD/AWD there are religious arguments about whether you should chain up the front or the back: I’d recommend starting with the front.
Also, not all snow tires are created equal and not all AWD/4WD vehicles feel the same. I’ve had our AWD Subaru with Blizzaks completely spinning out unable to get up a climb. My twice-as-heavy FJ80 with KO2 tires jaunted up the same climb minutes later without the slightest hesitation. So just because you see a vehicle doing something doesn’t mean yours can, and the other way around.
Step two: drive slow.
I have a heavy 4WD, high clearance truck, with aggressive snow tires. If it’s really gross out I’ll rarely drive over 20MPH. Highway, neighborhood, whatever: drive slow. If you have chains or cables on they probably have speed limits too. Plus, packed down snow (after a storm) is generally worse than deep snow for slide outs, and the next night after it went through a melt/freeze cycle can be really slick. Drive slow.
There’s an expression in snowmobiling and winter driving: inertia (speed) is your friend going uphill, and it’s your enemy going downhill. And definitely when going downhill there’s a difference between a slideout being an ego-bruising hour of shoveling versus t-boning another vehicle with kids in the back.
ABS (antilock breaking systems) work terribly in snow and ice, and your braking distance will be really magnified. One of the most common accidents is someone “braking” at a red light or stop sign only for the brakes to start ABS-jittering and the vehicle to happily roll straight into the intersection. Again, drive slow and watch the downhill momentum.
Step three: if it’s a storm or you see R2 conditions on the 395, take it seriously.
Bring a shovel (collapsible ones work), keep your winter gloves and jacket handy, and make sure you have a full gas tank. If you get near a half a tank, pull over at the next opportunity. Getting stuck for a couple of hours with your heater working fine is a little annoying, getting stuck with no heater can become an emergency in minutes.
If you do get emergency-stuck and it’s really dumping outside, make sure you keep the vehicle’s exhaust pipe in the back relatively shoveled out, the front grill relatively clear, and at least the occupied doors able to open if need be. There are deaths every year of carbon monoxide poisoning because the snow essentially traps enough exhaust gas under the vehicle which is where the air intake for the heaters pull from.
For most northbound drivers even in a big storm you won’t encounter much weather until the base of the Sherwin Summit, which you’ll start climbing a few miles after you leave Bishop. If there is a winter storm in Mammoth, this is where you’ll feel the first punch as you gain 2,400 feet leaving Bishop. If it’s not safe to go north just stay in Bishop at wait it out.
Step four: be visible.
White cars are cool but like an all-white snowsuit they are terrible for visibility. If it’s really reduced visibility, consider putting something on the back of your car to make it visible. And keep your lights on! If you’re having problems navigating the road, toss the hazards on. No one will get mad at you for signaling that you’re having a tough go of it and that you want to increase your vehicle’s visibility.
Step five: sometimes you need to wait it out.
The 16/17 winter here in the Eastern Sierra was epic by all accounts. We had the highest monthly snowfall ever recorded in the United States and even with our shovels, 4×4 rigs, traction devices, and related fancy gear, there were plenty of days where I looked out the window and just shook my head. We had to wait for the plows and blowers, we had to wait for the visibility to improve. Getting stuck really sucks when the conditions are so bad that people can’t even come help you.
The drive up the 395 is normally a total cakewalk requiring nothing other than typical safety. But mid winter in a storm things change fast. The thing you could have gotten away with six hours earlier can get now get you killed. Be safe, drive slow, and when in doubt just wait it out.