It sounds like she would be going up to ski fairly regularly. If that’s the case then winter tires would be a great advantage. She doesn’t want to wreck that Audi. Have the chains available just in case.
I’m in the area. The mountains just got up to 3 feet of new snow in the past 24-36 hours. That’s typical. The snow just dumps sometimes. The passes will close for avalanche control or if conditions are too extreme.
She should also have in her car a bag with blankets, food stuff, etc in case she gets stuck for hours. That is a real possibility here.
Buy good quality chains and practice putting them on, tightening, and removing them in all sorts of weather. I’m serious. Even if she doesn’t have to travel on the day of a storm, go outside and chain up the car just to see how difficult it is compared to on a nice sunny day.
It's kind of tricky when it's really just a few specific routes. The major highways are plowed. I've never gotten winter tires and went up to the mountains often once upon a time. But absolutely carry chains and learn how to use them. But that's really as a last resort since they're a huge pain to install and remove.
But Seattle doesn't really see much snow, although the might be a light dusting every year and some heavier snow every few years.
Seattle and the other cities don’t get the heavy snows on a regular basis but it’s surprising how little one has to travel before getting into it. It doesn’t take much to shut the cities down.
The other train of thought is to have the tools to avoid the nuts that cannot drive in even a ¼ inch of snow.
In Oregon "chains required" is often negated if you have "traction tires" on your vehicle and your vehicle's GVW is under 10k and you aren't towing. I drive through the Cascades often. If that exception isn't in place, the conditions are usually horrendous and you really shouldn't be driving. I believe traction tires are 3PMSF or all seasons if you're driving a 4wd or AWD if you read the statute.I believe chains are required by law in some areas. If she is required to have them available, I would prefer that they are as effective and easy to use as possible.