Coordinating the summit push

The last couple of weeks have been just waiting. We have been at base camp biding our time, spending our days walking, eating, napping, chatting and playing cards. It’s actually quite relaxing, provided you don’t allow yourself to get impatient about the next step – when will we be going up the mountain?

However, whilst the climbers have been resting there has been a lot of activity higher up the mountain. There is a lot to be organised; a lot to be moved into place, quite literally. Over the last couple of weeks Sherpas have been carrying loads up the mountain to supply higher camps. There are tents, sleeping mats, stoves, gas, food and oxygen that need to be carried to camps 3 and 4 ready for the climbers coming up.  As well as that, Sherpa teams have been fixing ropes to the summit.  These are safety lines that the climbers clip into in case of falls.

Waiting at base camp

This intricate dance is coordinated from base camp, often with cooperation between the major teams. Radio communications are imperative here for discussion between camps up the mountain. The Sherpas carry portable Icom radios so they can keep in touch with base camp.

Whilst all this is going on we are watching the weather. We are looking for a “window” of good weather – a stable period of about four days or so, particularly with low winds. When all the equipment is in place and the ropes are almost fixed then the teams start to move.  Early teams may move up to camp 2 and on to camp 3 to be in position for when the ropes are fixed and the winds drop.  Others will come later, due to personal choice or logistics.  For example, we have two groups, which will climb one after another with the same Sherpa support. Climbers can usually summit up until the end of May or into June before the monsoon comes, so there is time.

Helicopters fly in and out several times a day for logistics,  but are also important for rescue if anything goes wrong

An increased understanding of weather systems, and better computing and modelling capabilities have had a huge positive effect on weather forecasting over the last 30 years. This helps with planning on the mountain and contributes to improving safety, as does the improvement in reliability of communications. Being here on the mountain we can see the practical implications of these developments.

But perhaps the most noticeable difference in the field of communications is the connectivity at base camp that keeps us in touch with the outside world. There is NCell phone signal during daylight hours so that we can make phone calls home; camps have wifi powered by solar panels that keeps us connected via email, messengers or social media. Higher up the mountain we have satellite phones to keep in touch. This isn’t necessary to the safety of the expedition, but it is good for our morale and nice for family and friends.

So, whilst we are keen to get up the mountain and go for the summit, it has been interesting to get a glimpse of the logistics dance in action and to get an appreciation of how developments in science and technology improve the process.

The ‘Rotations’: Acclimatising for the Everest summit

In the two weeks since we arrived at base camp, we have been up the mountain twice on what are known as “rotations”.  These involve climbing successively higher up the mountain each time to get the body used to the altitude ahead of the final push for the summit.

Base camp. The view from near my tent.

Camp 1: Through the icefall

The first rotation was to Camp 1.  This was my first trip through the notorious Icefall, one of the more dangerous parts of the climb.  The Icefall is a tumble of ice blocks – a place where a river of ice drops over a cliff, splitting and breaking like a Snickers bar bent in half. There are crevasses opening like gashes. There are looming ice cliffs and tumbling blocks. The glacier is always moving imperceptibly. And through this subtly-changing landscape a narrow path weaves and climbs.

Aluminium ladders are lashed together and strung out over unskirtable crevasses. Going up is tiring, particularly the first time. The air is thin. Over-exertion – which may be as simple as hauling oneself up three icy steps – can lead to moments of unpleasant gasping and deep-breathing.

Climbers on the ice wall just beyond Camp 1

The first time I went up through the Icefall was hard.  I had not armed myself with snacks and water in accessible pockets and since we didn’t really stop at all – we want to get through the dangerous part as quickly as possible – I didn’t eat or drink for maybe six hours.

I was exhausted when we finally reached Camp 1. I had a rest day the following day while other team members made an excursion to Camp 2 and back in the morning. Since Camp 1 is a small camp with no cooking facilities, I spent most of the afternoon melting snow into water for drinks and food. It’s a slow process. We all descended back to Base the day after.

On my rest day, I was able to appreciate Camp 1’s surroundings.  After the Icefall, the glacier flattens out into the Western Cwm, a hanging valley at around 6,400m. There are still crevasses to watch out for, and some large undulations like huge waves in the snowy terrain around Camp 1, but the glacier is calmer.

Back at Base Camp we had welcome showers and washed clothes. I did some filming for my Everest video series. Otherwise we rested and ate and drank – very important here!

Sitting outside at Camp 1 with a view up the Western Cwm to Lhotse

Camp 2: Extreme weather walks

After a couple of rest days, we headed back up the mountain. I spent a night at Camp 1, then walked to Camp 2 the next day. The walk up the Western Cwm to Camp 2 is not too arduous – after climbing an ice wall and crossing a couple of ladders over crevasses it is a simple walk, and it is possible to get into a good rhythm. But it is incredibly hot!

The temperature variations in the Western Cwm are extreme. Before the sun hits, or when obscured by cloud, it is very cold (perhaps -10 to -20°C), but when walking in full sun in Gore-Tex it can be sweltering. The surrounding snow and ice reflects the sun’s rays so you are hit from all directions, almost as if the Cwm were a solar concentrator focussed on the weary climbers. Layers come off, thick gloves are changed for thin, sunhats and sun-cream are essential. But the air temperature doesn’t change with the sun up here. In the shade it is still freezing. Or if the clouds come in suddenly, it is as if the sun were never out at all. There is no happy medium.

Atmospheric optical phenomena, such as this 22 degree halo around the sun

We spent a few nights at Camp 2 with a couple of rest days to allow bodies to acclimatise. Camp 2 is also known as Advanced Base – it is much bigger than Camp 1 and teams have kitchen facilities and cooks, so at least food is not something we need to worry about.

One day we made a trip to the Lhotse face and up the first few of the steep pitches towards Camp 3.  I would have liked to go all the way to Camp 3 but it was not to be. Another rotation will be necessary. But it was good to get to the Lhotse Face and see what was involved, to feel that it is ok. It is a steep climb – not vertical ice but steep enough. There are fixed ropes that we haul ourselves up with jumars (devices that can be pushed one way but not the other, so they grip).  As we were climbing the clouds blew out and we saw the most beautiful rainbow halo around the sun.

 Jumar on the left and carabiner on the right

Back to base camp

Now we are back down to Base Camp.  It’s a relief.  It is hard work up there.  Even “rest days” aren’t really restful.  The extremes of temperature make it uncomfortable; the altitude means that it is easy to become out of breath when walking around camp, or even going to the loo! Everything takes more effort than it would do lower down.  However, we are able to experience an incredible environment that is open to so few.  The ice is beautiful – the way it twists and cracks and shines is lovely.  The clouds move in and out so quickly, they hug the slopes and create beautiful atmospheric effects. On the days that you don’t push your body to exhaustion you can appreciate the amazing nature of the place. It is magnificent.


Insulation 2 – a different lesson

Mountain Science – preliminary results 5

This post is about an experiment I did that gave quite unexpected results.

As well as looking at insulation of particular fabrics, as in the previous blog, I wanted to have a look at the insulating properties of some of my stuff – my socks and gloves.  I did this using a Raspberry Pi.  Anyone with a Pi can set theirs up so they can do this too.  If you do, please share your results with me.

The Raspberry Pi was set up with a temperature sensor and a real-time clock.  For information on how to do this see   When plugged in to a battery it boots up then takes temperature readings every ten seconds for 500s in total.  Then it turns off.

I did the experiments when I was confined to my tent during the snow storm on the way to Putha Hiunchuli.  Below is a picture of the items I tested: three pairs of Teko socks (thin, medium and thick); two pairs of Mountain Hardwear gloves (medium and thick); and a thin pair of silk liner gloves.


The experiment involved putting the warmed Raspberry Pi in a sock or glove, turning it on and putting the ensemble out in the cold while it took readings.  The Pi was warmed in my sleeping bag between readings.  This kept me occupied for most of the afternoon while we were snowed in.

When I returned to England I downloaded the data from my Raspberry Pi.  Unfortunately, not all the runs had saved properly, but what I have is plotted below.  Do you notice anything odd about this graph?  Would you accept these results?

Insulation Pi tent 2

Yup, it’s going the wrong way.  In the tent porch, according to this data, the Raspberry Pi was warming up not cooling down.  Hmmm.  This is a mystery.  I still don’t know why this happened.  Was the Pi placed too close to the battery and the battery heating up?  (See picture below of the grubby experimental conditions.)  It seems unlikely, but I have no idea why the porch was warmer.

Pi exp in tent

I repeated the experiment at home, this time putting the Raspberry Pi in the freezer as it took readings.  At home the Pi was in the bottom drawer of the freezer and the battery hanging outside so it couldn’t affect the Pi.  I did it just with socks this time, adding a very thick Teko expedition sock.  The results are below.

Insulation Pi home 2

These data look a bit more like we would expect – the Raspberry Pi is getting colder!  We can also see that the thicker the sock the warmer it kept the Pi, .i.e. the better the insulation.  The thicker socks trap more air, as discussed in the previous blog, so they keep our feet warmer.

This experiment is interesting because it teaches us to think about what we expect and not to accept the data blindly.  Repeat the experiment if necessary.  I should really do this one again somewhere else and compare my findings.  If anyone else does reproduce this experiment, please share!

Thanks to Zoltán Szenczi and to my sponsors:



Mountain science – preliminary results 4

This experiment looks at the insulation properties of three different fabrics – cotton, primaloft and down.

I did a simple test with my Vernier data logger and some samples.  I set the data logger up with three temperature probes and instructions to record the temperatures every 10 seconds for 20 minutes.  I placed a two-layer sample of each material in its own small plastic bag (except the down, which was just a load of feathers).  I then pushed one temperature probe into each bag between the layers of fabric or into the feathers so that it was completely surrounded.  I pressed record on the data logger and put it all out in the snow for about 20 minutes.


Later, when I downloaded the results to my computer, this is what I found.

Insulation FR 2

We can see here that the down is the most insulating material, followed by the primaloft, followed by the cotton.  Someone wearing just cotton would cool off quickly in the snow, whereas wearing primaloft or, preferably, down clothing would keep them warmer for longer.  This is because what actually keeps us warm is trapped air, and down traps the most air – caught between all the fluffy parts of the feathers.

One of the main ways that humans lose heat is by conduction.  In the same way that a metal spoon left in a piping hot drink will soon become hot to the touch, heat is conducted through any medium by hot, rapidly-moving atoms jiggling around and hitting into colder, slower atoms and causing them to jiggle faster, so transferring the energy.  Metal is a good conductor, meaning that heat energy transfers quickly through this medium.  Sitting on a metal bench in the cold will cool you down faster than just sitting in the snow.  Water is also a good conductor, which is why you will cool down quickly even in a warm swimming pool if you stop moving.  If you fell into freezing water and couldn’t get out you would likely be dead within ten to fifteen minutes.  But air is a relatively bad conductor, so trapping lots of warm air close to our skin keeps us warm.  This is why layering clothes is effective, with a small amount of air trapped between each layer.

The best insulating clothing therefore traps air.  Natural duck feather down is still the best material we have, despite creating fancy new materials.  However down is almost useless when wet, so can only be used in dry environments.  The man-made, synthetic alternative, primaloft, is not quite as insulating but it will maintain its effectiveness even when wet.  So remember, your best choice of clothing depends not only on what you will be doing, but where and in what conditions you will be doing it.

Insulation samples kindly provided by Will at Rab.  Cotton from the local haberdashery!

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Ultraviolet radiation at altitude

Mountain Science – preliminary results 3

At higher altitudes, the intensity of ultraviolet (UV) radiation increases because there is less atmosphere above to absorb the ultraviolet rays.  The UV intensity also increases the closer we go towards the equator, so climbers from the UK who go climbing in the Himalayas, say, will also see an increase in UV because of the change in latitude.  Snow and sand can increase UV exposure further, particularly in shaded areas, because they reflect the UV rays.

Ultraviolet radiation exposure can lead to sunburn, premature skin ageing and skin cancer, as well as causing eye damage (e.g. cataracts), so it’s really important that climbers protect their skin and eyes at altitude.

This is a picture of me wearing a hat and glacier sunglasses for protection.  I am wearing factor 50 sunscreen (and factor 30 lip balm) but still look a bit red.  I should be wearing my buff over my face to protect my lips and cheeks.

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When I was in the Himalayas I measured UV intensity at various altitudes, see graph below.  Although there is some variation, we can see that the intensity is increasing in both the sun and the shade.

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Since it’s so important for climbers to protect their eyes and skin whilst at altitude, I did some demonstrations using UV colour-changing beads to see the UV-blocking effect of my Julbo Monterosa glacier sunglasses.

Below is a picture of the UV beads in the sun – nice and colourful.  They are white in the dark, but in the presence of UV the beads become more and more brightly coloured depending on the UV intensity.


I put some beads in two pots and left them in my sunglasses case, out of the sun, to turn white.  When I took them out of the case I kept one protected by the glass of my glacier glasses and the other was exposed to the sun, as in the picture below.  I left them like this for several minutes.

Screen Shot 2014-12-18 at 18.02.04

Then I moved the sunglasses away and looked at the difference in the beads, see below.  The beads protected by the sunglasses were barely coloured at all (the colour creeps in quickly when the protection is removed) whereas the ones that had been in the sun were very bright.  At least this shows my Julbo glacier glasses were working!

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Julbo have several presentations on their website on the importance of eye protection.  For more information on UV radiation and sun health see the US Sunwise program and the UK Met Office.

Alongside Anturus I am making some videos of these experiments as educational resources, but these are some first results.

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Reduced air pressure & the body

Mountain Science – preliminary results 2

In the last blog we looked at how air pressure reduces at altitude and the effect this has on the boiling point of water.  This reduced air pressure also has a serious effect on the human body.

Reduced air pressure means that there is less oxygen available to the body.  There is still the same proportion of oxygen in the air (almost 21%) but the air pressure is lower so there are fewer air molecules per fixed volume of air.  This means that for every lungful a climber breathes there will be fewer oxygen molecules going into the bloodstream.

Doctors measure something called oxygen saturation (the concentration of oxygen in the blood).  Below 90% is considered low, and at sea level people with oxygen saturation this low would probably be sent to intensive care.  The interesting thing is that bodies can adapt to low oxygen environments and most climbers at altitude will have oxygen saturation levels below 90%, as I did for most of the time on my trip (see graph below).

Blood oxygen saturation, also called SpO2, can be measured using a little device that fits on our finger, called a pulse oximeter.  This picture below is me measuring my SpO2 at home before I left for the mountains.  You can see my SpO2 was 97% then.  The 57 is my heart rate.



The graph below shows how my blood oxygen saturation varied during the climb.  The blue “mountain” shows the altitude and the green points are my SpO2 measurements.  They are not tremendously accurate, but they give a clear picture of how changes in altitude affect the oxygen in the blood.

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In general, my SpO2 correlates quite nicely with the altitude.  At the beginning of the trip as we ascend the oxygen saturation in my blood goes down.  When the altitude drops my SpO2 goes up (e.g. around 12/10/12) and then drops again as we ascend further.

Unfortunately there are some data missing from the second half of the trip so we don’t get to see if my SpO2 increased as I acclimatised during the spells at a fixed altitude.  However, acclimatisation aside, it is clear that the reduction in air pressure at altitude has implications for our body.  The oxygen saturation in our blood – the oxygen available to our cells to keep the body alive – reduces as we go higher.

It is really important to be aware of this effect because oxygen is essential for our survival.  Every year people die of altitude sickness in the mountains when their bodies don’t get enough oxygen.  This can cause fluid on the lungs and on the brain, which can be fatal.  Mild symptoms are headache, nausea and fatigue.  Most people will experience mild symptoms, but if they are very bad or if you experience breathlessness at rest or confusion, clumsiness or stumbling you should go down immediately.

For more info on air pressure and oxygen levels, and for advice on climbing and altitude sickness, see  Also have a look at the Centre for Altitude Space and Extreme Environment Medicine (CASE Medicine) where they study the medicine and physiology of extreme environments.

Alongside Anturus I am making some videos of these experiments as educational resources, but these are some first results.

Thanks to my sponsors:


Air pressure at altitude

Mountain Science – preliminary results 1

I’ve recently been looking over the data I took while on expedition to Putha Hiunchuli in Nepal.  The plan was to take some data and do some experiments looking at basic science in the mountains, particularly around issues that affect climbers.  The main topics were:

  • reduced air pressure at altitude
  • increased ultraviolet radiation at altitude
  • reduced temperature at altitude

Alongside Anturus I am making some videos as educational resources, but here are some first results.

Air Pressure


Screen Shot 2014-12-18 at 20.25.26

Air pressure reduces with altitude.  That is, the mass of air pushing down on us is less as we go higher.

To look at the effect of this, I did something we do every day – I boiled some water.  We all know that at sea level water boils at 100 ºC, but look how this changes as we go higher.


Above is a picture of me with my Jetboil and my data logger up at 3675m measuring the temperature at which the water was boiling.

Screen Shot 2014-12-15 at 08.26.27

The temperature at which water boils reduces with altitude because the air pressure reduces.

Liquids turn into gases when they are heated because that heat energy is transferred to the particles of the liquid and causes them to move faster. When they are moving fast enough, the particles near the surface can escape into the air and become a gas. When a lot of liquid particles are escaping and the temperature stops rising we say the liquid is boiling.

However, in the air there are air particles that are pushing down lightly on the liquid and making it harder for the liquid particles to escape. A lower air pressure means there are fewer of these air particles pushing down on the surface of the liquid, so it is easier for the liquid particles to escape, so we don’t need to apply so much heat. Therefore the water boils at a lower temperature.

The way that water boils at a lower temperature is a demonstration of the affect of this lower air pressure. It can be a problem for climbers because they need to rehydrate their instant mountain food using boiling water. Water at 80 ºC doesn’t rehydrate food properly.

However, this reduced air pressure at altitude has a much more serious effect on the climber’s body – reduced oxygen.  I’ll show some results on this in the next blog.

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Putha Hiunchuli Expedition

The team stretching their legs after two sedentary days snowed in. Our Pangi ridge camp is in the background.

The team stretching their legs after two sedentary days snowed in. Our Pangi ridge camp is in the background.

I just arrived home from Kathmandu yesterday evening after a month in the remote Dolpo region of western Nepal. Nine of us plus guide and sherpas were attempting to climb Putha Hiunchuli (7246m).

Being home for such a short time, I’m struck by the juxtaposition between my life here and what I’ve been living for the past month. I thought I had masses of stuff out there – two full duffel bags and a bit extra in a rucksack. But I’ve come home to a shelf full of makeup, boxes of stilettos piled behind my bedroom door, kitchen cupboards full of different shaped glasses and variously-patterned mugs, and I almost miss the simplicity of a face-wipe and a metal cup. It has happened before. These superfluous things will soon become normal again.

Besides readjusting, I am able to reflect on the expedition. It was not a success in black-and-white terms. We didn’t summit Putha Hiunchuli – we didn’t even come close, not even making it to base camp – but I don’t feel disappointed despite the implications for my future plans in not having attained the altitudes, and thereby gained the experience, I would have liked. The expedition was a success in that as team we walked into a remote region, dealt with various surprises and issues that befell us and remained safe, well, happy and unified.

We were caught up in a cyclone that unfortunately caused several casualties in Nepal. But we had up-to-date information and strong leadership and we set ourselves up somewhere safe, at the top of the ridge above Pangi Camp, out of the main avalanche risk area. We were snowed in at 4500m for several days. The snow was deep and impassable to the yaks that usually carry expedition equipment to base camp. We couldn’t get up, but equally there were others there who couldn’t get down.

I summarised our predicament to the tune of the Bee Gees Tragedy, which will serve here as an unofficial trip report.

Epic of Pangi Camp

At this level we can’t expect all our expeditions to result in a summit. There are too many factors that need to come together and many are out of our control. Failure always teaches us something, but I don’t even think of this as a failure. It was a beautiful experience. And I’d like to thank my entire team – westerners and Nepalis alike – for inspiring, supporting and amusing me for the past month. I will miss you.

The ridge when we arrived, just before the storm.

The ridge when we arrived, just before the storm.

During the storm.

During the storm.

The ridge after the storm.

The ridge after the storm.

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