Skip to main contentSkip to main content
You have permission to edit this article.
editor's pick

Dahl column: How to tow safely over snowy passes

  • 0

Travel over mountain passes can be very dangerous in the winter months, and when trailers are involved, it only gets more difficult.

Doug Dahl


Q: What are the rules for towing a trailer over the pass when there’s snow or ice on the roads? And beyond the rules what advice can you give? I suspect the real concern is trailers on ice, since they may not want to follow the tow vehicle.

A: I recently checked mountain pass conditions on DOT’s website, and now is a good time to be talking about this. Before we get to the rules though, I have one question for anyone about to tow a trailer over a pass with winter conditions: Do you really have to make that trip right now?

If you answered, “yes,” you’ll need some chains, and what you’re required to do depends on the combined weight of your tow vehicle and trailer. If you’re less than 10,000 pounds you follow the regular chain requirements. When “chains required” is posted, drivers towing a trailer must chain up their tow vehicle, but chains aren’t required on the trailer. If you’re driving a four-wheel or all-wheel drive, you’re not required to chain up, but you must have chains in your vehicle.

Vehicles or combinations over 10,000 pounds gross vehicle weight rating (GVWR) have their own set of rules. You might think that beyond 10,000 pounds we’re just dealing with commercial vehicles, but it’s not hard pass that weight with a full-size pickup and a large RV. Even a pickup alone can do it. If you’re driving a pickup that exceeds 10,000 GVWR these rules are for you too. When “chains required” is posted, all vehicles, including four-wheel drive, must chain up and, if you’re towing a trailer, that includes at least one trailer tire. You’re required to carry two spare chains, and plastic chains are not allowed. You also need to carry tire chains with you between November 1 and April 1 if you’re driving over one of a dozen highway passes listed in the Washington Administrative Code (and also available on DOT’s website).

That’s the rules, but there’s so much more to safe winter driving than having tire chains. Here are a few key winter driving tips: Check road conditions before you head out, drive slower, leave more room between vehicles, plan farther ahead for stopping, and have an emergency kit on board. I’m sure you can think of more.

Those all are even more important when towing a trailer, plus there’s more. Fishtailing and sliding are major concerns; managing that properly takes properly adjusted trailer brakes and experience knowing how to respond to icy road conditions. Setting up your trailer brakes is a project beyond the scope of this article. Just know that if you don’t do it right, you might end up with your trailer passing you while it’s still connected to your tow vehicle. In case anyone’s wondering, that’s bad.

I remember the first good snow after I got my driver license. I took my car to a big empty parking lot and discovered, in a low stakes environment, what it felt like to lose control in bad weather. Maybe don’t try the same thing with a truck and trailer, but the idea behind it is valid. You don’t want your first experience having your trailer tires break loose on ice to be on a road where not getting it right has dire consequences.

That’s the catch-22, isn’t it? You don’t want to tow in snow and ice without experience, but you’ll only get experience by towing in snow and ice. I can’t solve that, so here’s the advice I’ve taken from drivers with experience towing trailers: Keep it parked until the roads are clear.

Doug Dahl is a Target Zero Manager for the Washington Traffic Safety Commission and a former deputy sheriff. Send him a question by visiting his website,


Catch the latest in Opinion

* I understand and agree that registration on or use of this site constitutes agreement to its user agreement and privacy policy.

Related to this story

Most Popular

Get up-to-the-minute news sent straight to your device.


News Alert

Breaking News