In reply to CasWebb:
> It was binned because one group ran out of time to finish the shelter before the snow storm hit.
Precisely. Wrong shelter, wrong place.
Most people build those shelters leaving big packs behind in the morning. Then go off for a half a days skiing etc.. the sas on ops aren't going to bury all their vital equipment in snow then stand around waiting to see if they or their snow shelter freeze solid first.
Better to read the map, the contours, consider previous prevailing wind, then find a drift. Even if you don't finish it before the storm hits, you'll be inside to some degree and out of the worst wind on the lee side etc.
Or as I said, find a large spruce with low sprawling branches. There is very little snow around the trunk. 15mins and one person could make a shelter for 4 people to survive. Wind protection and a natural roof.
There are better ways to survive when not on tv. Ie. 500gram 3x3m plastic sheet or bothy bag.