Not your typical case, if I understand correctly.

They certainly met the pass/fail test very well. (Pass = alive and well.)

Given they were professional medical personnel, they were certainly capable of recognizing/avoiding dehydration and hypothermia. So they wouldn't call for rescue before they needed it.

As to a mountain blizzard, this can whip up pretty easily, and not with any specific warning. A bit of falling snow, a bit of wind to whip up loose powder, and all you know for sure is that you're on Planet Earth, somewhere north of the equator.

Compass and crude map would have helped, but you need to check the compass regularly before you need to navigate. I can't imagine carrying a GPS at a resort, but I've never carried one anyway, seems like dead weight.

My only thought (which I should apply to myself!) is that when you're in doubt, and have a cell phone signal, you call someone reliable and say "hey, we're okay, but a little turned around, here are the details just in case, if you don't hear back in 24 hours pull the SAR trigger."