Search This Blog

Sunday, July 17, 2011

Extreme Cold Weather Skiing

I have never been a big skier, having never lived in a place where it snows.  I have skied downhill a handful of times, and, before coming to the South Pole, I had only cross-county skied maybe a dozen times.  Nevertheless, knowing that people had skied all the way across Antarctica, I thought that skiing should be a fun outdoor activity at the South Pole.  Before leaving home I inquired with some veteran Polies and I was told that the South Pole station had plenty of skiing equipment, but the gliding would be poor, and it would not be possible to ski in the winter, as the temperatures would be so cold that the skis would nearly freeze solid with the ice.  Prepared with this grim outlook, my expectations have far been exceeded.  Since arriving at the Pole last November, I have skied almost every day: in the summer, in the winter, with temperatures down to -70 C (-94 F), and I have been having a great time, so I decided to write this blog to let future generations of Polies know that it is indeed possible and enjoyable to ski year round at the Pole, and also as a way to record the clothing and equipment that I used, my experiences about what worked and what did not work, so that I might use this blog as a future reference in case I decided to buy some of the equipment for my personal use, or for the benefit of anyone else who might be considering doing some skiing in extreme cold environments. 
Steele took this picture of me on July 1, outside of the Martin A. Pomerantz Observatory (MAPO), about ½ mile from the station.  The temperature was -63 C (-82 F), and  it was blowing a 16-knot (18 mph) wind. 

The glide: is there actually any glide here at the South Pole?
The short answer is that yes, there is some gliding, but very, very little.  To quantify the gliding I took some data point earlier in the season, at the end of March, with temperatures around – 60 C (-76 F).  I counted the number of steps that it took me to ski the 400 ft (122 mt) distance between two sets of flags along the skiway.  I did this several times in three different conditions: 1. Forcing myself not to glide; 2. using my regular Nordic ski pace; and 3. trying to glide as much as possible using the skating technique.  With no gliding it took me an average of 146 steps to cover the distance, meaning that my step was 2.6 ft (80 cm) long.  This is about the same as when I walk.  When I used my regular Nordic ski pace it took me an average of 92 steps to cover the same distance, which corresponds to a step length of 4.3 ft (132 cm).  Therefore, the gliding per step was 132 cm – 80 cm = 52 cm.  Using the skating technique and trying to glide as much as I could, it took me an average of 66 steps to cover the distance, which corresponds to a step size of 6.1 ft (185 cm).  In this case the gliding was 185 cm – 80 cm = 105 cm.  I am not sure how this compares to warmer conditions, but I suspect the gliding here at the Pole is inferior.    Another way to compare the skiing conditions here at the Pole to other locations is by comparing the speeds obtained during races.  In the McMurdo marathon on the Ross Ice Shelf here in Antarctica, on Jan 16, and with a temperature close to freezing, the winner in the ski category completed the 26.2-mile course at an average speed of 10.5 mph, while here at the Pole, on Dec 25, and with a temperature of -12 F (-24 C) the fastest skier on the much shorter 2.2-mile course of the Race Around the World skied at an average speed of 5.4 mph, and he was an experienced ski racer from the Northeast, who had even competed in the Marcialonga in the Italian Dolomites.  So, the speed here at the Pole is about half of what it is at temperatures closer to freezing.  Therefore, the gliding must not be great, but we can ski and have a good time nevertheless.  I have been skiing at a speed of 3 ~ 4 mph, closer to 4 in the summer and closer to 3 in the winter, which is kind of like a fast walk.  I have not tried to wax the skis.  I have talked to numerous adventurers last summers who skied to the Pole, and none of them was waxing their skis.  I guess the wax loses its gliding properties when it gets too cold.  The gliding is probably affected not only by the temperature, but also by the quality of the ice.  There is no snow here at the Pole, as the temperature is too cold for snow flakes to form.  Instead, precipitation comes in the form of ice crystals, which are only about 0.01 mm in size, much much smaller than snow flakes, and invisible when they are in the air.  The ice crystals remain on the ground as a powder.  They only aggregate together to form solid ice under their own pressure several feet under the surface.  Also, there is no melting and refreezing here at the Pole, so the surface is a constant dry powder all year round, with a thin crust on the top.  The ice crystals make a screeching sound under the pressure of the skis that can be heard a long ways away.  The friction between ice crystals is in my opinion where the energy of the forward motion of skiing is absorbed. 

The clothing
I ski an average of 5.5 miles each day, which takes me a couple of hours, so warm clothes are necessary.  I have found that the equipment provided by the US Antarctic Program is excellent and perfectly adequate for this activity, so I would like to give its description here.
I start with an under layer of cotton socks and longjohns.  The top, made by Kenyon,  is 100% polyester, and is commercially available; the bottom is 100% polypropylene, it is made by Peckham Vocational Industries and does not appear to be commercially available.

Then I put on heavy wool socks, or more precisely, 95% Worsted Wool and 5% Nylon.  Ours are made by Wigwam Mills.

Then comes what we call the Carhartt.  Carhartt is actually the name of the manufacturer.  This is a fantastic piece of equipment, one of my favorites of the entire wardrobe provided by the program.   These are insulated work coveralls with multiple pockets suitable to hang tools.  They are designed for outdoor work, and they are very sturdy, although not indestructible.  They even have a hook on the back, which I used in the summer to attach a rope to and haul a sledge.  I did this several times when I was skiing with Dr. Weatherwax to different locations on the ice carrying equipment to calibrate fields of cosmic radiowave antennas.  I use one of the two pockets on the front bib to hold my UHF radio and the other to hold my music player.  These coveralls are made of a 100% cotton exterior shell, a 100% nylon internal lining and a 100% Polyester insulating interlining.  They are listed on the Carhartt website as style R02, and list for $110.  So, staying warm in extreme cold weather does not necessarily require extreme $$$.  In general, cotton is not considered to be a good material in cold weather because it absorbs water and stays wet a long time, but there is no water here at the pole.  When we are outside the ice never melts, even when it sticks to our clothes, and when we walk back into the station the air is so dry that the ice seems to turn into vapor without going through the liquid phase.

We have several options for ski boots.  My favorites for the winter are made by Karhu, model Convert.  They top my list because they are the warmest.  They look like sturdy walking boots, with good insulation, and have three pins in the Vibram sole to fit the bindings.  Although these are the warmest boots we have on station I still use our Grabber foot warmers and toe warmers.  These are small packs containing a mixture of iron, water, activated carbon, and salts.  When exposed to air, the chemicals in the packs react with the air to provide heat.  They last several hours.  I am not sure how effective they actually are at our temperatures.  While they definitely provide plenty of warmth at room temperature, it looks like either the reaction slows down when temperatures get colder, or the heat generated just isn’t enough to compensate the heat lost to the environment.  Nevertheless I still use them, as they provide at least some extra insulation.

Then comes the balaclava.  I have used a couple of them through the season.  The one I have now, from Outdoor Research, is made of Windstopper fleece, and is very good.  It has lasted the whole winter, through an average of 3 hours of use every day, and through multiple washes, and still looks like new.

After the balaclava, I put on my wool hat from Nepal, and then my Northern Outfitters 100% polyester fleece top.

The third and final top layer is the very famous red parka.  This is by far the most amazing and valuable piece of clothing that we are issued.  I have never, ever, felt cold wearing it, even at -100F (-73 C), and even with the strongest winds that we experience here at the South Pole, provided of course that I do not stand still.  My feet are actually getting cold before I can feel any cold through the red parka.  In the very rare occasions when the wind chill has dropped below -140 F (-96 C), I could just start to feel the wind through.  The red parka, originally designed specifically for the US Antarctic Program, is now also a commercial product.  It is called the Expedition Parka and it is made by Canada Goose.  It has an 85% polyester/15% cotton shell, a 100% nylon lining, and a 625-fill white duck down.  It has coyote fur around the hood.  When the parka is zipped all the way up the hood cannot be lowered, which means that it will not come off even in the strongest winds.    The hood protrudes several inches forward from the face in what we call the snorkel, so as to create a chamber of warm air around the face.  In addition, the edge of the hood has a metal frame which stays rigid even in strong side winds.  If the wind ever makes it into the hood, all I have to do is to close down the opening of the hood by bending the metal frame.  This way I lose a little bit of visibility, but I can fend off the wind.  This parka also has a multitude of internal and external pockets which I use to carry small tools, emergency flashlight, fresh batteries, pencil and paper.

After the parka come the three layers of gloves.  The first is just a pair of thin wool liner gloves – the blue glove visible on my left hand in the picture.  The second is a pair of leather mittens.   The lining is 65% polyester, 35% rayon, and the insulation is made of 3M Thinsulate material.  I use hand warmers in the mittens.  They work just as the foot warmers and toe warmers that I described earlier.  Hand warmers are very effective at keeping the hands warm.  I am not exactly sure why they seem to work so much better than the foot warmers, but I suspect that the hands remain fairly warm, so that the hand warmers do not have a chance to freeze.

Finally the bear paws, and I am ready to hit the ice.  The bear paws are gauntlet mittens made by the Illinois Glove Company.  They have a 100% wool shell with leather sewed to the inside of the palm and pile fur on the outside, and an insulating detachable insert.  I found them necessary when temperatures drop below -50F (-45C).

The ski equipment
The US Antarctic Program provides us with a good selection of ski equipment.  Every item comes in a variety of sizes.  I have tried most of the equipment available to find what works best for me.
The first combination available is skating skis and boots.  The skis are made by Fisher, model BC Country Crown.  The bindings are snap-in Fischer Autoflex 105 Profil SNS.  The boots are Fischer Combi 5000.  I found this to be the best combination for the summer.  I ski mostly Nordic style, but occasionally, on a good surface, I like to skate.  These skis and boots allow both styles.  The only problem with this set is the extreme cold, and I am talking about temperatures at or below -50 C (-68 F).  Around these temperatures feet get cold after less than one hour, the rubber in the bindings becomes rigid so that it becomes impossible to snap the boots into the bindings, and the boots become sort of brittle.  I broke the metal rod in the boot, where it attaches to the binding, with no apparent stress.  This is why, at the beginning of April I started experimenting with different skis.

This is the second pair of skis I used.  They are telemark skis, with metal edges, made by Karhu, model Lookout.  The boots are Karhu Convert, and the bindings are made by Rottefella.  The great thing about this set is the boots.  They are well insulated and much warmer than the boots in the previous set.  They also fit very well.  I have tried different sizes and none of them ever produced a blister or any discomfort.  I found the best fit in a boot two sizes larger than my shoe size, which allows room for the heavy socks, foot warmers and toe warmers.  I have been able to ski for up to 3 hours at temperatures down to -90 F (-68 C) before my feet started getting cold.  However, the skis are significantly slower, probably because of the additional friction produced by the larger surface area.  It took me about 30% more time to cover the same distance using these skis as compared to the Fischer BC Country Crown.  These skis, weighting 8 lbs with the bindings, are also much heavier than the Fisher skis, which weight just 4.5 lbs including the bindings.  Unfortunately, most of the Karhu boots that we have on station have cracks, either in the Vibram sole or in the top leather, or in both.  I believe the cracks are due to the cold.  While cracks in the leather are mostly an aesthetic flaw, cracks in the sole are a big problem.  My first boots had a small crack in the sole, which eventually propagated and resulted in the sole breaking and the boot becoming useless.  I took a second pair of boots and made sure they did not have cracks in the sole to begin with, and I have now skied more than three hundred miles in them with no sign of damage.   To prevent causing damage to the Vibram sole I do not skate and I try to move slowly when on rough terrain, but I suspect that a potential cause for the damage to the boots is the fact that we currently store them in an unheated building, so I am looking for a storage place inside the station to better care for them.

I found the best winter combination to be the lightweight, low-friction, Fischer skating skis with the heavy-duty Karhu Convert boots.  This however requires a different type of binding, of which there are only two on station: the Norwegian-made Rottefella Super Telemark three-point bindings.  These bindings have worked very well at any temperature down to -94 F (-70 C), as they are purely mechanical.  Now I can get the speed and the warmth at the same time.  I don’t think I will be too hot in these boots even in the middle of summer, so I vote this as the best kit for recreational skiing at the South Pole.

The ski trails

Here is a map of my ski trails.  All distances were measured with a GPS.
Before I close I want to pay a tribute to Steele, our very competent machinist, who braved the -82 F (-63 C)temperature and 16-knot winds on July 1 to take photos of me outside.  When not at the Pole, Steele lives in Tasmania, an island off the coast of Australia.  This is his second winter at the Pole, and he may come back next year for a third.  I first met him at Fire School in Denver back in September of last year.  He has made several parts and modifications for my various projects, is a true gentleman, and is a great pleasure to share stories with.  He is also currently building next year’s Pole Marker, which will be unveiled at the Geographic South Pole during the Pole Marker Ceremony on Jan 1, 2012.


  1. Excellent detail - thank you for sharing!

  2. At last a post that's practical and of great service to me. Thank you