There was a wee chat on my Mountaineering Club Facebook page about the best sleeping bags for winter. I have had years of suffering in many mountains in the UK and abroad. I learned lots on my early walks in the 70’s but choice was limited.
I have a great Rab bag that I used on Everest on despite being heavy was well worth the weight. I spent so many years snow holing I learned that it was so worth the extra weight to be warm and comfortable. I had done many bivouacs but in 1990 on Kusum Kangru we had to sleep out at about 18000 feet just in our bivy bags it was an awful night. We had no sherpas after Base Camp.
The name Kusum Kangru comes from Tibetan meaning “Three Snow-White Gods”. At 6,367 m, Kusum Kangru dominates the southern end of Charpati Himal and separates the valleys of the churning Dudh Koshi from the upper reaches of Hinku Drangka.
The mountain is complex having at least five major ridges and faces, the most spectacular of which is the North face of the main summit. It is one of the most difficult of the trekking peaks to climb.
The first successful ascent of the main summit was made by Bill Denz of New Zealand on 7th October 1981 via the South-West buttress. He also completed the first solo climb and traverse of the mountain, descending via the northwest flank. A Japanese team had previously reached a subsidiary northeast summit on 9th October 1979
A 1988 British Expedition led by Nick Mason conquered the previously unclimbed East Face. In subsequent years new routes have been opened but all of them are technically very challenging.
25 years later in Alaska I learnt so much. Yet the thing that made the – 25 temperatures bearable was carrying two scrims. I could sleep well despite the cold and good insulation is a great comfort. It’s not bad for a one night bivy in my opinion but for a 3- 4 week expedition I went for comfort despite the weight. Various other expeditions to Pakistan, India and the Himalayas all built up my thoughts on insulation.
Sleeping mats are so different from the early days I remember using cardboard on my Duke of Edinburgh Award in the late 60’s and even old papers. Things moved on a lot of simple kit designed by the military to foam scrims and later insulated mats. The world was a lot simpler then.
Needle Sports info https://www. needlesports.com/Catalogue/Camping/Mats
“Camping Mats come in all shapes and sizes. There are broadly speaking two types, Foam Mats and Inflatable Mats. Both sorts come in different thickness and made of different materials and as always the customer has to choose between mountaineering’s ever conflicting parameters of efficiency, weight, bulk and cost.
Typically used in the British textile industry, one Tog corresponds to the heat insulation capability of clothing etc which maintains a temperature difference of 0.1°Kelvin while passing a heat flux of 1 Watt/m2*. Some manufacturers (mainly US ones) give an R Value for the insulation properties of their mats. By this they mean an imperial equivalent (°F-ft2-h/Btu). To convert Imperial R values to Togs, multiply by 1.76228. To confuse matters there is also a metric R value, more properly called an RSI value (10 Togs = 1 RSI).
The higher the Tog or R (or RSI) value the better the insulation provided.
If you aren’t totally confused by the above you should add to the mix that testing for R/Tog/RSI ratings is not by any means an exact science and that it is also expensive so, it is alleged, some figures that are given may be acquired by doing little more than taking a competitor’s figure and adding a pinch for good measure. Of course, who is alleging what about whom is also not easy to ascertain!
*NB One Tog was originally a war time measurement of the amount of warmth retained by a typical male wearing a three piece suit – it originated from research done in the North of England – hence the term tog (though this in turn is thought to originate from the Roman word toga)!”
Nalgene water bottle and insulated container makes a great hot water bottle and gives you water for a brew in the morning. Top Tip.