RE: How do you keep a tent warm at 11,000 ft ?
Charcoal ???? probably the most toxic fumes available, we camped at about 10000 ft and used a propane ceramic heater to warm up the tent before going to bed, then turned it off including turning off the propane supply . next morning first up had to fire up the heater worked fine for us , about 11 degrees in the A.M. below 0 bag and thermal foam pad worked great plus if you sleep with your head out of the bag wear a thermal ski cap to bed.