I went to bed the previous night with a thumping headache because of the altitude. I had a similar thing when I was climbing Mount Kilimanjaro and knew that this could be alleviated by hydration and resting to acclimatise. But I woke up several times in the night and every time I moved my head, I could feel my head thumping, which was not a good sign.
When I woke in the morning, it was actually a brilliant day for summiting Mount Vinson. It was perfect weather with very little wind, but I still had a major headache and told the guide I needed a rest day. I took diamox, which is an altitude acclimatisation medicine. It is not an immediate fix for the acute mountain sickness I felt, but it speeds up part of the acclimatisation, which in turn helps to relieve the symptoms.
Mark and Scott decided to try and take advantage of the weather and go from high camp to the Summit, but two hours into their walk, they turned around and came back to high camp. Mark was also feeling the effects of the altitude and also needed a rest day.
The altitude at high camp is 4,000 meters, but because the air is so thin at the poles, the occurring altitude is almost 300-400 meters more than the actual. But again, we had great weather. The temperature in the tent went up to 20°C in the sun, but as soon as the sun went behind the mountain leaving us in the shadow, the temperature instantly dropped to -8°C.
One of the criteria to do anything here is to make sure the route is in the sun and not the shadow, as it can make almost 30 degrees difference. With 24-hour daylight in Antarctica during the summer months; weather conditions and how we respond to the altitude, rather than clocks, dictate our activities and schedule and “time” takes on a different meaning.
I hoped the weather the following day would be as good, as the route to the summit is exposed making it sensitive to strong winds. Summit day is expected to be our longest day of climbing, 9-12 hours, so I needed all the rest I could get to acclimatise properly before summiting Mount Vinson.