I'd second the hand warmers -- a fast cheap way to warm up. Ditto the high calorie food ( granola bars) and water. The biggest change I'd make is adding a snow shovel for digging.

as an aside: i'd make up kits for those I'm hiking with: just a ziploc with a bandana, 4 granola bars, a lighter two jumbo trash bags, whistle and a couple of hand warmers