My thanks to a helicopter pilot for this fascinating email and for permission to share it. And for adding the ‘ptarmigan altimeter’ to my collection!
Just finished your book, The Walker’s Guide to Outdoor Clues & Signs, as part of my reading before a Mountain Leader assessment next Spring (travel restrictions and Christmas waistlines permitting, of course).
I was struck by your topographic compass – uphill downhill, upstream, downstream. With your aviation experiences you may have already used a similar model of the world around you when flying adding the other directions of ‘upwind, downwind, crosswind’.
Search & Rescue crews at Inverness, Prestwick, Caernarfon and Stornoway in particular spend much of their time searching for and recovering the injured, lost or unprepared in the hills. An immediate cross-over of your compass might lie in keeping track of how one would get out of a tight spot if the weather clamps in or with a loss of power, eg ”escape will be crosswind towards that cliff 11 o’clock (to pick up any updraught) uphill from the tarn on the nose with the wind lanesfrom the left and the birds above it (wind indication), left descending to pick up the stream downhill of the trees (which can make their own clouds and even turbulence, plus are spiky) and out downstream over the river valley fields (because they will be flatter with shorter vegetation if we have to turn an escape into a landing)”. The more the terrain goes up and down, the more up- and down- prefixes are used to move through it – running-in and flyaways from next to a sea cliff or a ship are much more 2 dimensional. Then there are the visual clues, such as wind lanes on lakes or waterfalls going up and flattening greenery or where the herbivores are, to show subtle movements of the air. Caused by temperature profiles, surface friction and the shapes of the hills around you – turbulent edge, recirculating eddies downwind of a ridge or in a bowl feature, katabatic winds in the morning or Foehn Effect threats the other side of a hill, these bring pros and cons to power demand, hover references and turbulence (which is nobody’s friend). All this can play differently on 11 tons of helicopter upstairs than it will on 100 kg of winchman hanging up to 300’ below.
Judging local sunset with your fingers, for example, has long been something I’ve told people about, but it takes on a more fluid dimension when you’re moving at the time, downhill of 1000’ or more of mountain side. Much as I imagine it does for you and your compendious bag of clues & signs, one starts to feel all these things, rather than consciously analyse them: I daresay you’d quickly feel quite at home in a helicopter.
Other than enjoying such parallels, my appreciation of the book means that I now notice how Monty, the old, soft cat down the road, is barely worth a peep of communal notice from the garden birds any more, but that they have different shouts for the sparrowhawk (move! get under a bush) and the tawny owl (mob! we’ll chase her away).
Also, my favourite natural barometer is that if you see a ptarmigan, and especially if you see 2, you’re probably already over 3000 feet – oh and either you’re moving in a neighbourly fashion as they don’t allow themselves to be seen by those that crash about, or you’re approaching a nest and you’re being lured away.
Thank you very much for the book, best wishes and remember ‘it’s better to stop and then land, than to land and then stop’.
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Picture credit: Windy Miller, Bristow Helicopters