Good time for a refresher on this after the group of 4 from SD spent 5 days on the mountain in the snowies.
I have not heard there story yet, but I have been in the same situation in the snowies back on new years eve 2005/2006.
Some things that came in VERY handy for us was rope, a 8x10 tarp, headlamps, saws, a way to boil water, and multiple ways to start a fire.
The rope and tarp is an easy and fast way to make shelter or a wind block. Cut pine bows to sitting on so your insulated from the snow.
When building a fire, be aware that the fire is going to burn itself down to dirt...5,6,10 ft down depending on the snow pack. Also if your tucked into the trees, the fire will melt snow above you in the trees and water will drip down, and chunks of snow will fall... on you
You will burn A TON of wood! the nights are long and cold, and you will be getting fire wood very often. This is where the headlamp comes in very handy so you can find, cut and haul wood with both hands. This is also why I always carry more then one saw... One in my shovel handle, a folding one in my pack and on my sled.
13 yrs ago we didnt have a spot or inreach or sat phone, but we did have more then one GPS's units with us and a tri-mode cell phone to dial 911. Any old cell phone will dial 911, those old phones with the pull out antennas is what allowed us to get our location to SAR (call made in analog emergency service mode) and got us off the mountain in 36 hours.
Also carry way more water then you need, and some of those soup packs that you just add water too sure is nice to have along with you.
Also, one thing we wished we had but didnt, was something like a book or a deck of cards..... time goes by very slow!