Summer Alpine Bags: How light is too light? image

Summer Alpine Bags: How light is too light?

December 10, 2009

Reading Time: 20 minutes.| Comments: 1

Hi Andy
Just wanted to quickly pick your brains on sleeping bags.  At the minute I have two sleeping bags, one is a lightweight RAB quantum 250 and my other is a RAB summit 900.  I tend to sleep quite warm so for summer alpine routes I’ve got a couple of options one is that I use my quantum 250 with a lightweight bivvy bag (would this put me at risk from getting very cold/dead?) or I could use my quantum 250 with my shiny silver survival bag thing which would increase the warmth and it’d hopefully give me some protection from the elements.  My final option which is my least favourite is to buy a warmer bag and a bivi bag. 

Thanks a lot.


Hi Tom

I think a 900 bag would be over the top for alpine stuff (summer or winter!) unless it’s for a high base camp, and a bag like the Quantum 250 is fine as long as it doesn’t get really cold (I’ve used a 450 in the Alps in winter, which was very borderline).  Some climbers still go without a bag at all (I remember Jules Cartwright telling me he’d never taken a sleeping bag on a summer alpine route), and alpine nights are shorter and not too cold.  Personally, I think the weight of a light bag is worth it, as it both gives you a good nights sleep (on the route and at the base), plus it gives you a confidence boost you can bivy, instead of pushing on when it’s not a good idea.

When cutting the loft of your sleeping bag to a minimum here are a few thoughts.

Make sure your bag is as good as it can be (light bags from people like Western Mountaineering and PHD stand out, along with ME, Exped, Rab etc).

Make sure the bag is long enough so you can sit in it with your helmet on.  If you can’t you’ll lose a lot of warmth.

Get a superlight bivy bag that breathes well and has a full hood.  Goretex is the most storm proof but is heavy, bulky and expensive.  Half and half bags (PU and gore) don’t work for alpine stuff either, and I’d probably go for an Epic bag, or make my own out of proofed Pertex.

Take enough clothes with you to boost the heat of the bag, including dry socks.

Don’t skimp on the food and fuel either, as this will help keep you warm.

Extra fuel will allow you to fill up a Nalgene bottle with boiling water and use it as a hot water bottle.  Some climbers also use those charcoal burners to add some extra warmth, plus you could use heat pads.

If you’re expecting a tough night, then go to bed late (finish in the dark and take your time brewing up), and get up early, meaning you’re static for as short a time as possible (less sleep - if you can - but also less suffering if you can’t).

Using a bothy shelter will boost your warmth (I’ve been trying to get Terra Nova to make an unproofed one designed for climbing, but so far no luck), as will spooning up, or zipping two bags together.

I’d avoid non-breathable survival bags unless it’s a life or death situation (you’d use it close to your body inside your sleeping bag like a vapour barrier).

Also as you’ve got a down bag, make sure it’s in a light waterproof stuff sack, as Alpine routes can get pretty wet!

A good article to read is Colin Haley’s on bivy systems.  There’s also this article on my site

Hope that helps.



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