Stranger than fiction............

 

Holger Danskes Briller trough, south-facing slope at the western end of the eastern lake.  The two huge rockfall avalanche ramparts are very prominent.......

In my novel "Icefall Zero", set in East Greenland ion 1962,  one of the critical incidents is a sudden rock avalanche which overwhelms and almost kills two of the heroes, in a glacial trough containing two large lakes.  The trough carried diffluent ice from the huge glacier that once flowed along Nordvestfjord. (See some recent posts.........)

When we were in East Greenland in 1962 we never got a good look at the trough because of bad weather, and its slopes were mostly enveloped in low cloud. Our maps and air pohotos were also of very limited use.  When I wrote the novel in 2014 the information was not much better, and satellite images of the area were of poor quality, partly because the details of the valley sides were often lost in deep shadow.  But I thought the steep slopes looked unstable, especially in the middle section of the trough, where there are some high buttresses and peaks over 1000 m high.

So I invented my rock avalanche and described its effects in graphic detail in the story..........

Imagine my surprise when I examined the new Bing / TomTom satellite imagery  some weeks ago and discovered amazing detail of the slopes in the trough, especially on the sunny (south facing) flank.  There are multiple gullies on the cliff face, with long histories of intermittent rockfalls and probably snow avalanches too.  But there are two especially prominent features, characterised by huge ridges or ramparts at their bottom ends.  These are much more likely to have been the result of single sudden catastrophic slope failures.  Such features are very common in NW Iceland too, beneath steep basalt cliffs subject to pressure release following deglaciation.

Each of the ramparts is about 200m wide.  On the satellite imagery the ramparts and upslope scree slopes have slightly different colourations, suggesting to me that the eastern one is somewhat youngerc than the western one.  How recent were these slope collapses?  At the moment, the jury is still out, but I would hazard a guess and suggest that they may be very recent, from within living memory.  In 1962, maybe.....??

I would not have liked to be anywhere in the vicinity when either one of these slope failures actually happened........