That one is truly tragic! It seems if she'd have just had a sleeping bag and didn't run the car she'd have been fine. This is probably the situation I'm the most prepared for! I'd be comfy down to about -40 F or maybe a bit lower, got a pair of Wiggy's bags in the Subaru at all times. Plus a pair of Wiggy's mittens, some hats, extra gloves, a pair of Wiggy's Arctic Pac boots, saw, axe, shovel, small tent, tarp, ground pad, tow strap, etc. Usually I've got a couple of Mountain House LRP rations in there as well not that it's a strict necessity. If the car is doing the hauling why not be prepared? That reminds me, I gotta go throw my crampons in the car!