They do get totally covered by snow - as a matter of fact, they are in a garden that gets covered by all the snow that is plowed down our driveway - sometimes that can be 5 ft. high depending on the severity of our winter.
When the snow melts, there are a few black/dead pieces, but I cut those off, and the rest perk right up just as soon as it warms up. I have a large area that is in bloom now, but it doesn't like pictures apparently - none that I've taken show the true colors well.
By the way, we lived in Reno for 7 years, and that is what got me so interested in cacti/succulent plants. Tahoe is such a wonderful place to live, it was only about 20 minutes from us - so jealous of you!