please explain how one can die from hypothermia in 70 degrees? sorry but just dont cut it.
being exposed to a temp that is 28 degrees below your body temp for too long can eventually lower your core temp. if it goes below 96(i think) degrees, this is when problems can start to occur.
almost always, some form of moisture is the cause of enough heat loss to create enough heat loss. we learned about this in cap, as most pilots never pack any sort of survival gear in their aircraft(we have survival packs in all of our aircraft with protective gear and water for 3 people). thus, when we go out on an SAR mission, it is imperative that we get to the approximate scene, and locate them very quickly.
EDIT
this may be a better explanation than i offered.....
http://www.outdoorplaces.com/Features/Mountain/hypothermia/