Not to knock the 4 hikers... but they appear not to have been very well prepared for the weather and location either... One pair of dry socks, One t-shirt, an overshirt and a sweater as extra clothing for 4 of them?! No hot drinks, stove or snacks (not to include a meal) at 4pm with at least a 2 hour walk in the cold back to transportation.
...they were set up for needing rescue themselves