By the way, tea lights are pretty good too, provided you take the proper percautions.
Indeed! For all you dataholics, a table of snow shelter temperatures I got from an old instructor shows:
Outside Inside Conditions
Temp (F) Temp (F)
+4 +8 No door - unoccupied several hours
-2 +7 No door - unoccupied several hours
-7 +14 Canvas door - unoccupied
-14 +21 Unoccupied 2 hours - 1 candle - door
-14 +24 Half-hour occupied - 2 candles
-49 +20 1 occupant - no heat
-48 +23 2 occupants - 2 candles / 15 minutes
-55 +19 2 occupants - overnight - no heat
The only citation is "Scandinavian Airlines: Survival Manual"
Also, when using a chemical heat pack, optimum placement when sleeping is probably over the femoral artery.