Location N 71 27.89 W 046 52.50
Distance (day/total) 125/329 miles
Weather Strong katabatic wind and and sunshine for most of the day Wind 15-28mph Temp -10c
First of all some news from last night. We were chatting about the sudden onset of the pitterak winds found mainly in SE Greenland. These winds build up in little time and reach speeds of over 100mph and flatten tents without hesitation. Within 10 mins of discussing this, we heard a distant roar, and immediately thought – pitterak, but a few seconds later it sounded more like a low flying jet. Unusual to say the least in the wild remotes of the ice cap. The roar got louder and louder and I thought, bloody hell, that jet is low, and just as I imagined it overhead the tent went -BANG – the side bounced in and we both looked at each other, eyes wide open. What the hell was that?. I dived out of the tent expecting to see some burning wreckage, but there was nothing apart from snow. We then spent the next half hour trying to work out what it was; we concluded it was probably a sonic boom from a military aircraft overhead. We were due to have a change of underwater on day 6 anyway..
So back to today; early 3am start to get camp broken down for a 5am launch of the kites. Perfect conditions saw us average 20mph until we hit sastrugi at the 50 mile mark. Sastrugi are wind formed ridges of snow and can be up to one metre high. It is like skiing a mogel field on a piste. Not kind to the knees, especially 51 year old vintage. We keep going though and after 9 hours set up camp. A total of 200km done today, our best so far (or 125 miles in old money, but it doesn’t sound so good)
We were blessed with the infamous katabatic wind today. This is one of the features of the extreme weather found here.
A land of extremes:
Temperatures of minus 70 degrees Celsius in the Northern part of the ice cap in winter, to plus 25 degrees Celsius on the coastal areas in July. 3.5 metres of precipitation in Southern areas to nearly no precipitation in the cold artic deserts in the far North. Stretching 700km from the North pole to a Southern latitude on a level with Oslo in Norway the World’s largest Island is geographically placed to “enjoy” large annual variations in daily sun exposure. In the North there is midnight sun for nearly a third of the year although this is counteracted with a third of the year in winter darkness. No wonder Greenland has some unusual characteristics – with the 1.7 million square km Ice cap (80% of land mass) topping the list. And it is this Ice cap that potentially provides us with a steady wind source for our kites as we travel Northwards.
The cold surface air in the centre of the ice cap is denser and heavier than the surrounding air and consequently will have a tendency to want to move downwards towards the coast. This type of wind is termed Katabatic and when climatic conditions are settled gives us a predictable, reliable and plentiful source of power. In the map below those winds can be seen blowing away from the centre of the Ice cap towards the coast with the higher wind speeds being experienced in the steeper terrain. There is a slight twist, quite literally, as the Earth’s rotation bends the wind’s direction slightly clockwise, thus giving us a small component of tail wind to speed our progress.
Source: Danish Metrological Institute – Technical Report 00-18
To enable us to make sense of the subtle variations in the wind patterns we have enlisted the help of Marc de Keyser at Weather4Expeditions who will be providing us with daily updates on the short term forecasts for our location. With this information we can plan, in rough terms a target heading and also determine the optimal time to travel (for instance the katabatic winds can be stronger during the night due to the larger temperature differences)
Marc has given us a late start for tomorrow so we will catching up on some sleep. Sorry no photo of us today we have little power as the sastrugi shocks caused the solar panel cable to jump out of the battery (twice!)
Thanks for following our adventure,