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July 2015 Issue
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How to get a good night’s sleep in the cold

A sleeping mat is the most important shield from the cold. Photo: Phil Gradwell

Insulating yourself from the ground is the most important factor in getting a good night’s sleep, writes Whitney Thurlow

 

The first thing you need to know about cold weather sleeping is that what you lie on, is way more important than what you sleep in.  

Cold ground or snow will suck the heat out of you fast. Only by separating yourself from the ground will your sleeping bag be able to do its job. Inadequate insulation on snow will have you waking up shivering even with the warmest sleeping bag money can buy.

Sleeping mats have an R-value to indicate how much insulation they provide. The standard foam mat has an R-value of one, mats designed for cold ground and snow use go up to 5.9.  

Self-inflating closed cell foam mats are most common – think Therm-A Rest – and typically have an R-value of between two and four. In really cold weather, you may find this is not enough. In which case, here’s what you should do:

  • Put everything not being used beneath you. Climbing ropes are easy to flake out to the right shape and sleeping on an empty pack is not as bad as it sounds. Food bags and any clothing not being worn can all go under your sleeping mat. A bumpy bed is way better than a freezing one.
  • Even the best sleeping foundation is of little use if you roll off it at night. Many mats have a slippery surface and even calm sleepers can wake up freezing, lying beside their mat. The cunning solution is to shape the snow or ground beneath your tent into a body length shallow groove before creating your nest. If the ground is frozen, a line of flat stones under each side of your sleeping pad will keep you in line all night.

If sleeping on your pack seems a little hard core then you may not be ready for how your empty water bottle can prevent the need to get out of your bag in the middle of a cold night!

– Whitney Thurlow is chief guide at Aspiring Guides, Wanaka