When the Pass Closes Behind You

Interstate 80 over Donner Summit is the main road between Sacramento and Reno, and in winter it is a road that can be taken away from you with very little warning. Planning a crossing means planning for the version where you do not get across.

Why it closes

Rarely because of snow depth alone. Closures usually come from a combination: snowfall rate outrunning the plows, spinouts blocking a lane on the grade, a jackknifed truck, whiteout conditions, or all of them stacking up within an hour. The summit sits high enough that a storm arriving as rain in the valley is arriving as heavy snow up there, and the transition happens in a fairly short stretch of road.

What actually happens to you

Closures on I-80 do not simply stop traffic at the summit. They back it into Colfax, Applegate and Auburn on the west side and into Truckee and beyond on the east, and the vehicles caught in between sit where they are. Two things follow. First, you may be stationary for hours in a place with no services and limited shoulder. Second, when the road reopens, everyone who was waiting moves at once onto a surface that is still marginal, which is when a lot of the low-speed damage happens.

Plan a crossing you can abandon

• Check conditions at the bottom, not at the top. Caltrans posts current chain requirements and closures; look before you start the climb.
• Know your bail-out points. Auburn and Colfax on the west, Truckee on the east. Deciding to stop somewhere with rooms and food beats being stopped somewhere without.
• Do not treat State Route 20 or Highway 49 as an escape. Secondary mountain roads in a storm are usually a worse version of the same problem, with less plowing and no traffic control.
• Leave earlier in the day. Most of the hard hours on the summit are after dark, and daylight makes every part of this easier.

The reopening is its own hazard

When a control point releases, the queue moves as a block. Drivers who have been sitting for two hours are cold, frustrated and running late, and the pavement under them is packed snow that has been sitting under stopped traffic. Low-speed impacts in that release surge are a large share of what our office hears about after a storm weekend. There is no prize for being at the front of it.

Being stopped is not being safe

If you are stationary in a lane on a grade, the vehicle that matters is the one arriving behind you that has not realized traffic has stopped. Keep your foot on the brake so the lights are lit rather than sitting in park with everything dark, leave room to the vehicle ahead so you have somewhere to go, and stay in the car. Getting out and walking around on an active mountain freeway is worse than the boredom.

What your policy is doing during all this

Two coverages carry the winter mountain risk. Collision responds to your own vehicle in an impact, including the slow-speed slide into the car ahead in a release surge. Comprehensive responds to things that are not collisions — a tree limb under snow load, a rock coming down a cut, damage from a falling object. Neither is required by California law and both are optional unless a lender requires them, which is exactly why so many people making this drive discover they do not have one of them. If you cross the Sierra several times a winter, it is worth pricing both rather than assuming.

Get collision and comprehensive quoted together before the first storm rather than after.