Reports of 3 climbers/walkers falling over a Cornice in the Cairngorms in Coire Cas and falling several hundred feet will be in the news today. They were lucky getting away shaken with only a broken ankle and heavy snow to break there fall. Many are not so fortunate, when the weather gets wild as it is now with high winds and snow the Cornices are huge.
Today’s Cairngorm Forecast
“Southerly in the range 50 to 70mph, with gusts 90mph but may ease 40mph
for a while just after precipitation clears.
Effect of wind on you? -Walking often difficult from lower levels upwards and any mobility torturous higher up. Severe wind chill.”
Add to this limited visibility and if in the mountains navigation is extremely difficult. In this the mountain and situation merges into a “Grey Room” where it is impossible to make out any features and Navigation and dead reckoning is the only way to travel safely. It can become a near impossible to move without these navigational skills and it is simple to make an error and walk over a Cornice. Many experienced Mountaineers have been in this situation and have walked over a Cornice and on Rescues it is easy in wild conditions to make an error that could be fatal. I had a mishap many years ago on Creagh Mheaghaidh near Laggan when my dog Teallach when young walked over a Cornice in a white out and I thought he was a goner. I was with a very young group of novices, the weather was extremely poor and we had just climbed the other two Munros. A big storm was raging by now it was late in the day and we were wearing head torches. Navigation in a day like this is mentally exhausting and the last two hours coming from the Window to the summit and then off were incredibly challenging. I thought we had missed the bad ground but was out by 100 meters when Teallach vanished into the gloom. I heard a thud and a thump as the Cornice went!
We roped up and I managed to relocate and work my way down a ridge. My young group were in bits and I was really upset. There was no chance of looking for the dog, getting off was priority! Out of the gloom about 1000 feet below, I was calling him expecting no response when he bounded up the ridge, he was unhurt. The weather was a bit better lower down and he had found us, thank god. Teallach after that steered us away from danger over the years, he could tell where huge Cornices lurked and was such a great companion on the hill. We had made several mistakes in the “Grey room” I struggled with my vision, I wear specs and did not have prescription goggles so had to work at reading the map and changing bearings. We thought we were nearly home and I had switched off.
I had not eaten or drunk for ages and now make sure if the weather is bad to have a snack in my pocket and” graze” whenever possible. Many of us push on and forget that the body needs fuel like a car to function. MISTAKES ARE MADE OFTEN ON THE WAY DOWN.
Never switch off till you get down to the car and safety. Goggles are essential in winter, practice navigation in a safe area and always have a map and compass for each of the party. There were no GPS in 1982 we were lucky – will you be?
A snow cornice or simply cornice is an overhanging edge of Snow on a ridge or the crest of a mountain and along the sides of gullies. They form by wind blowing snow over sharp terrain breaks (e.g. the crest of the mountain) where it attaches and builds out horizontally. This build up is most common on the leeward sides of mountains. Cornices are extremely dangerous and travelling above or below them should be avoided.
When a cornice collapses, it breaks in from the cornice to the top of the peak; even being on the snow on top of rock exposes the mountaineer to hazard in this situation. The best practice in mountaineering is to stay far enough back from the edge so as not to be able to see the drop, as an approximate metric of exposure. Of course, this is not always possible. .
In Avalanche safety, cornices are a high avalanche danger as they often break and trigger larger avalanches that permeate several snow layers. Cornices are particularly vulnerable to collapse during periods of solar warming.