Comparative Fuel Efficiency and Carry Weight for Six Lightweight Backpacking Cooking Systems: Part II

[Bob Gross]

The easy recommendation is this:

However much fuel you would need for a summer trip, for a winter snow trip, double it.

–B.G.–

[Roger Caffin]

> However much fuel you would need for a summer trip, for a winter snow trip, double it.

+1

Cheers

[Michael Matiasek]

Thanks for the fast responses, but I am not sure I understand the logic for doubling.

This is my thought process so far; doubling it seems fine and all but I find that I drink a lot more ambient temp water than I heat for hot drinks and cooking food. In the summer I boil at least 1.25-1.5L per person per day. But for drinking on the trail and in the evening I would want to have around 3L total per day. This means I have a total of 4.25-4.5 L of water required. I was under the impression that the energy required to melt snow is similar to the energy required to heat ambient water to boiling. So if this is the case, would I need 3 times the amount of fuel that would be used on a summer trip, where snow melting is not required. Thanks for your help!

Mike

[Derek Goffin]

Yes Michael in some circumstances treble it. however if you put snow in your water bottle and put the bottle inside your coat as you walk you can melt some snow by body heat whilst moving. Thats good if you are too hot not so good if you are fighting for warmth.

[Roger Caffin]

> I am not sure I understand the logic for doubling.

Very simple. It takes a certain amount of energy (=fuel) to heat water from typical creek temperature to boiling point. It turns out it takes about the same amount of energy to heat cold snow up and melt it to give water around 'creek temperature'. Hence the recommendation to double.

This suggests a huge fuel saving if you can dig down to running water. You betcha!

Cheers

[Bob Gross]

Oh, yes. When cross country skiers are out for a long trip in the springtime, they have all sorts of tricks to be able to grab liquid water out of a stream, so that they don't have to melt snow.

A good one is to attach a length of wire or cord from the bottom end of your ski pole, and then to attach that to the neck of your water bottle. Then you edge up next to the stream bank and try to dip that into the water. If you screw up, either you get an unexpected bath, or you will lose the water bottle.

You can load a thin layer of snow into a clean black garbage bag, and leave that out in the sun on a big rock. You come back later, and you have a part of a bag of liquid water that tastes slightly like plastic.

–B.G.–

[Tait Kjellberg]

Bob, that is exactly what I do. When snow camping, I take a large new black garbage bag. The first thing I do when setting up camp is to fill it about 1/2 full and lay it on a hill side with one of the lower corners at the low end. The next day I pinch just a tad off that corner. Enough for the water to trickle out. I dig a well and set my pot or nalgene under the trickle. Once full, boil for food or drink away. Refill the bag as necessary. This works like a charm!

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