By light, I mean warmest temperature rating.

A bit of background: This summer I'll be headed to Denali with a climbing partner who recently moved to Fairbanks. I exclusively do trad, alpine, and big wall climbing in the lower 48, but I've been to the Alaska Range once before in 2002. My memory of that trip is fuzzy, and my style has evolved considerably since then (one of my first climbing trips).

I err on the side of being light, because I prefer to sleep in all of my insulation (heck, I'm carrying it). In the lower 48, I typically use a 40 degree bag and sleep in my insulation (done winter in the Whites). I'm also resolutely a synthetic guy, so the idea of dragging a -20 degree synthetic up Denali doesn't sound fun.

How light a bag can I get away with if I'm sleeping in my insulation?

The way I go for temps down to about -10 is to use my 2 lb 1 oz 15 degree down bag with my 1 lb 14 oz 40 degree Big Agness Cross Mountain synthetic bag as an overbag. This combo per the manu ratings takes me down to -5, but I've done fine down to about -15 with just a light fleece and thermals on inside this sub 4 lb combo and the Cross Mountain sheds moisture nicely too. It's fair to note I'm a warm sleeper...

I used a high quality bag rated to about -15 and was barely warm enough at 17k with all my clothes on and my parka draped over my bag. It was a particularly cold year (-30 at night). I am generally a very warm sleeper and used a +15 bag for Hunter, the Ruth Gorge and several winter ascents of Rainier.

I would really re-think the synthetic thing for AK. I live the Cascades (think wet) and favor sythetic for here, but in my trips to the AK Range, I have never been disappointed with down. It is dry enough that down works very well there.

Get a vapor barrier liner for your bag. Keep you warm, less snow to melt (to drink), and keep your bag dry. I recommend getting one with a zipper so it is easier to get in and out of. I hate worming my way in and out.

I have camped out in fairbanks at -20F and was warm enough. I spent 2 weeks there, and during the day, I used a VBL shirt, pants, gloves, and socks. I rarely wore any insulation, except for gloves and a hat. I wore black diamond climbing pants, and sometimes an uninsulated shell. I did wear pile pants and a shell while lying down digging a snow cave though.

lopgok wrote:Get a vapor barrier liner for your bag.

Experiment with VBLs before going to Denali. VBLs work on the concept that you wear only a light base layer to bed, making all clothes you brought useless for bed. The old saying is still true: "If you didn't wear all your clothes to bed, you brought too many."

I save about a liter a night by using a VBL in the desert. I also stay nice and warm. I thought in the Alaska Range there are few streams to fill up water bottles, and you melt all your water. I presume that means time and fuel.

A VBL will keep you warmer than pile clothing, and will keep your sleeping bag dry.

lopgok wrote:I thought in the Alaska Range there are few streams to fill up water bottles,

Yeah, its basically a huge ass glacier. I don't know a single active, successful AK Range climber who uses a sleeping bag VBL and I know a lot of successful AK Range climbers.

ExcitableBoy wrote:

lopgok wrote:I thought in the Alaska Range there are few streams to fill up water bottles,

Yeah, its basically a huge ass glacier. I don't know a single active, successful AK Range climber who uses a sleeping bag VBL and I know a lot of successful AK Range climbers.

So a glacier will generally have low humidity, meaning moisture tends to evaporate quickly. This is a perfect place for a VBL. Integral designs used to sell a VBL liner bag. I presume they still do. I know several companies sell VBL for socks and gloves. I fear people that are not using VBL are hard men, but definitly not smart men. People perspire in order to keep their skin moist. It is called insensitive perspiration. When humidity is low, you do it more. It also happens to cool you as the moisture evaporates and it also takes water to work. It is basic human physiology. The way to minimize it is to be in a high humitidy environment, as provided by VBL.

Side benefits are you stay warmer, your insulation stays dry, and no ice builds up inside or on top of your insulation.

Cheap people use plastic bags for VBL socks or latex gloves for VBL gloves.

I fear the successful AK Range climbers you know are stuck in the stone age. I wouldn't be surprised if they would use ash wood shafted ice tools, if they could find them to purchase.

'Will Steger faced a problem unique to extreme cold. Body moisture would go through the sleeping bag only so far before it hit the bitterly cold outer layers and froze. By the end of the trip Steger and team were lugging sleeping bags that has gained as much as 50 pounds of condensced frozen moisture.'

Where do you suppose the moisture came from?

See http://books.google.com/books?id=-d8DAA ... &q&f=false

lopgok wrote:

ExcitableBoy wrote:

lopgok wrote:I thought in the Alaska Range there are few streams to fill up water bottles,

Yeah, its basically a huge ass glacier. I don't know a single active, successful AK Range climber who uses a sleeping bag VBL and I know a lot of successful AK Range climbers.

So a glacier will generally have low humidity, meaning moisture tends to evaporate quickly. This is a perfect place for a VBL. Integral designs used to sell a VBL liner bag. I presume they still do. I know several companies sell VBL for socks and gloves. I fear people that are not using VBL are hard men, but definitly not smart men. People perspire in order to keep their skin moist. It is called insensitive perspiration. When humidity is low, you do it more. It also happens to cool you as the moisture evaporates and it also takes water to work. It is basic human physiology. The way to minimize it is to be in a high humitidy environment, as provided by VBL.

Side benefits are you stay warmer, your insulation stays dry, and no ice builds up inside or on top of your insulation.

Cheap people use plastic bags for VBL socks or latex gloves for VBL gloves.

I fear the successful AK Range climbers you know are stuck in the stone age. I wouldn't be surprised if they would use ash wood shafted ice tools, if they could find them to purchase.

'Will Steger faced a problem unique to extreme cold. Body moisture would go through the sleeping bag only so far before it hit the bitterly cold outer layers and froze. By the end of the trip Steger and team were lugging sleeping bags that has gained as much as 50 pounds of condensced frozen moisture.'

Where do you suppose the moisture came from?

See http://books.google.com/books?id=-d8DAA ... &q&f=false

Jesus Christ.....no one there hauls 50lb sleeping bags! Regular down bags WORK, GREAT. If you use it correctly. The only way I could see a sleeping bag weighting 50lbs is if I took a shovel and filled the bag up with snow, and than pissed on it so it freezes overnight.
Your system is interesting, but not required.

lopgok wrote:I fear people that are not using VBL are hard men, but definitly not smart men. I fear the successful AK Range climbers you know are stuck in the stone age. I wouldn't be surprised if they would use ash wood shafted ice tools, if they could find them to purchase.

Colin Haley, Mark Westman, Joe Puryear (RIP) are my friends. Between the three of them, no currently active climber has done as many significant ascents in the AK Range as these three. They don't use VBL bags.



Colin Haley and Mark Westman on yet another AK Grade 6.

lopgok wrote:So a glacier will generally have low humidity, meaning moisture tends to evaporate quickly.

Not where I'm from. Maybe after you do some actually CLIMBING in the AK Range, not just camping in the backyard, your considered opinions might have some sway.

Ouch! Smack down!

The main issue with VB is that many, if not most, people don't understand them and have not learned how to properly use them, but are quick to attack others regarding them.

While it is nice to say that others don't use them, the most important aspect is whether those people have bothered to try a VB and learn about how to properly use it. If they have not tried it, then it is bogus to make negative claims since there is no personal experience to base it on.

With non-VB bags, people don't learn to properly vent, allowing the moisture to accumulate in the bag or parka since the feedback is greatly reduced. This can lead to the item gaining weight. Try weighing your bag at night and then again in the morning if you want to see an example.

Take a look at the HANS device in racing. Many negative things were said about it, especially from older drivers, like Dale Earnhardt, but had he used such a device, it might have saved his life.

So, have you actually tried a VB? Have you learned how to properly deal with it? Or do you prefer to just follow the crowd and say that the earth is flat?

mistdaemon wrote:The main issue with VB is that many, if not most, people don't understand them and have not learned how to properly use them, but are quick to attack others regarding them.

While it is nice to say that others don't use them, the most important aspect is whether those people have bothered to try a VB and learn about how to properly use it. If they have not tried it, then it is bogus to make negative claims since there is no personal experience to base it on.

With non-VB bags, people don't learn to properly vent, allowing the moisture to accumulate in the bag or parka since the feedback is greatly reduced. This can lead to the item gaining weight. Try weighing your bag at night and then again in the morning if you want to see an example.

Take a look at the HANS device in racing. Many negative things were said about it, especially from older drivers, like Dale Earnhardt, but had he used such a device, it might have saved his life.

So, have you actually tried a VB? Have you learned how to properly deal with it? Or do you prefer to just follow the crowd and say that the earth is flat?

please enlighten us about all the advantages. Also let us know how much does one weight and how much warmer it makes you?

Vitaliy M. wrote:please enlighten us about all the advantages. Also let us know how much does one weight and how much warmer it makes you?

Google is your friend:
http://www.integraldesigns.com/product_ ... N=78268781

The HVBL (shown above in an XPD3 bag) is designed to keep a down sleeping bag dry on multi-day trips by preventing body perspiration (up to half a cup a night) from getting trapped in the down. The HVBL will enhance a sleeping system in a number of ways: 1. It reduces dehydration by lowering an individual’s perspiration rate once skin senses that it is in a humid environment. 2. It adds warmth to a sleeping bag by trapping an extra air layer and reducing evaporated heat loss (up to 5º). 3. It serves as an emergency bivy when out on an extended day trip or climb.

In dry conditions the heat generated by the body will drive moisture through the down. However, in extremely cold or humid conditions, some of this moisture may become trapped in the down and freeze. By using a HVBL the moisture is contained and can be removed by turning the HVBL inside out and shaking off the flakes as the moisture freezes. The HVBL is made from ultra-light Silcoat nylon, has a contoured hood with a draw-string and cordlock to fully contain moisture and reduce liner slippage and has a large foot box ensuring a non-constricting fit.

"On an expedition to the North Pole in 1986, Will Steiger's team used synthetic-filled sleeping bags (and didn't use VB liners). By the end of the trip, the bags had gained about 35 lbs (16 kg), roughly a pound each night, in accumulated ice". Clyde Soles ( Rock & Ice 2000)

6.5oz $85


http://www.integraldesigns.com/product_ ... cfm?id=672

These comfortable and simple waterproof socks are designed as a layer to be worn between inner and outer socks to trap the moisture from sweaty feet. This will ensure that socks and boot liners stay dry, keeping the feet warmer and reduce the possibility of chafing and blisters. VB Socks are made from a soft 70 denier taffeta nylon with .5oz urethane coating and are seam taped. They are also elasticized at ankle level for a snug fit. The tops are designed to extend beyond boot tops to calf level, and are secured with shock cord and a cord lock.

http://www.westernmountaineering.com/in ... ntentId=44

This fire engine red vapor barrier liner is your most important companion for those technical winter trips. A VBL works by stopping heat loss from evaporative cooling. A VBL will also prevent your body vapor from degrading your insulation. This is most important during extended stays inside your bag. Our Hot Sac™ VBL goes one step further by stopping radiant heat loss with its reflective metal coating. An elastic draw cord at the top of the Hot Sac™ cinches about your neck to prevent convective heat loss. This proprietary fabric is a new lightweight ripstop. The new Hot Sac™ weighs only 4.5 ounces and is light enough to carry on day trips as an emergency bivy.