Snow-holing in Scotland has a long established history in both our own winter mountains and further afield. Over the last 10 years, snow-holing has grabbed the attention of the media and the viewing public. This exposure has introduced and encouraged people happy enough to pay for the experience. Andy Bateman* of Scot Mountain Holidays asks, should we assume what works in other mountains will work well in our own?
Likely Ambient Temperature
With the seasonal minimum in some recent Scottish winters approaching -20oC and an official record of –27.3oC, you would be forgiven for assuming you’d might be sleeping in temperatures approaching those of Arctic Norway.
Yet Cairngorm (1245m) has only ever recorded around half of this at –16.5oC (12th Jan 1987). Supporting this, Coire Cais Ski Base Station (630m) has a low of -9.2oC. The residents of nearby Nethybridge (210m) though, claimed the mercury dropped to -31.3oC on 10th January 1982. Satellite evidence suggests they were right!
The vital bit of information on these -30-ish lows are that they were all recorded during temperature inversions. The cold air flowed off the mountains and pooled in the valley bottoms where it cooled further whilst the mountain summits remained appreciably warmer. These record minima are in no way a reflection of the likely temperature you would find on our mountains. It’s not surprising when we’re never that far from a relatively warm sea in the UK!
So what temperature is likely when snow-holing in Scotland, let’s say, in the Cairngorms at around 1100m? The seasonal minimum for 900 m is usually around -8oC. At 1100 m this could translate to -10oC. Far more frequently winter temperatures at this height are around -5 and above. Our mountains simply don’t experience anything like the temperatures you might get in e.g. Arctic Norway.
Considering the warmer temperatures when snow-holing in Scotland, do we really need snow-hole features designed to capture warm air? Are sleeping platforms and cold air drains really necessary or should our aim be to lose the warm air?
Snow is a great insulator. A meter thickness in your roof and front wall is of vital importance in this regard. That is 20 cm of insulating snow both on the exterior and interior surfaces with 60 cm of well insulated structurally sound snow. Light penetrates to a depth of around 75 cm so if you see daylight, they’re getting too thin. It should also be borne in mind that a 1 m thick roof represents a considerable weight. It’s vital the front wall is adequately thick and strong enough to support the roof.
How high is that roof? Look at the apex centre.
Snow-hole sites by virtue of their high snow accumulation and steep slopes can be prone to avalanches. To be safe, you may need to pick a slope with a more gentle gradient and spend more time digging out the entrance. The majority of avalanches occur on slopes at or above 30 degrees. To maintain a 1 m thick roof, on a slope less than this, you’ll have to dig in a minimum 2+ horizontal meters from the top of the doorway before you start widening out the living area.
Avoid large areas of unsupported roof by keeping your snow-hole narrow. Aim for a depth of 2 body widths between the internal surfaces of the front and back walls.
This means you can create a relatively steep-angled apex ceiling which helps to avoid any drip points. Warm air can then be channelled towards the ventilation holes at the apex high points. In addition with it running the length of the snow-hole it increases the height with minimal snow removal giving everyone the opportunity to straighten their weary backs!
Importantly it also removes the unsupported dead weight from the ceiling. This is one of the most important aspects of snow-holing in Scotland. Although not mutually exclusive, removing the ceiling dead weight is of more importance to ceiling stability than temperature! Very few, experienced and inexperience alike, pay attention to removing the dead weight. I’ve managed to snow-hole once at +5 Deg C without any roof deformation! The roof of a snow-hole I constructed for the BBC Travel Show lasted through until around the 25th June!! The ceiling at that point was only a foot off the floor, but it hadn’t collapsed!! Every other snow-hole at that point was merely a hollow in the snow. As you create the apex be careful not to make the roof too thin. The strength of the roof is in it’s thickness.
Here you can see quite clearly the shape of the apex centre for our snowhole.
Make sure there is good ventilation. My test is to regularly watch my breath. If it drifts off to one side it’s a good indication that ventilation is adequate. Cooking with pressure stoves in a poorly ventilated snow-hole is extremely dangerous due to the formation of toxic Carbon Monoxide. All pressure stoves work by first oxidising the fuel to Carbon Monoxide (CO) and then to Carbon Dioxide (CO2). The different colours in the flame indicate this. Irrespective of good ventilation a pan of icy water can have a severe quenching effect on the flame preventing combustion of the CO. Research for the British Antarctic Survey (BAS)** showed in heating a pan of icy water CO production could be significantly reduced by raising the pan supports higher above the flame. Snow-holers should acquaint themselves with the symptoms of CO poisoning.
To put this into perspective, I’m unaware of anyone in the last 25 years dying from CO poisoning whilst snow-holing in Scotland. I do know though, instructors who’ve attributed head aches to possible CO poisoning. It’s worth considering taking a small portable CO detector with you. In a snow-hole with a single entrance and no through air movement, ventilation may well be inadequate. Extinguish candles before you go to sleep as they also produce small amounts of CO.
Although the temperature may remain around 0oC you may well still be “injecting” appreciable heat energy into the snow pack. It takes considerable heat energy to turn snow at 0oC into water at 0oC so it will not be reflected in a temperature rise. It’s far more desirable that this heat energy drifts out of the doorways than being absorbed by the snow pack.
Make it large enough to stand up in. Large communal snow-holes are less prone to an abrupt temperature rise as they have better ventilation characteristics by virtue of having several entrances, etc. An entrance walled up with blocks in combination with an open doorway will often still allow plenty of ventilation.
Putting aside the dangerous scenario of cooking in a poorly ventilated snow-hole, I’ve never got up in the middle of the night to purely unblock a doorway for ventilation reasons. All the medical research I have seen (references below) doesn’t suggest there is any potential of becoming severely hypoxic in your sleep. Studies suggest sleep will become agitated, you will awake and in doing so get up and ventilate a stuffy snow-hole.
One potential hazard of digging a small snow-hole is you don’t have enough space to put the snow as you attempt to extricate yourself after a night of severe drifting. On one occasion I did have to tunnel out 1 ½ m before I hit the surface!
When it comes Scottish snow conditions, don’t underestimate how hard the snow can get. You will need a snow shovel with a metal scoop and a good snow saw. The sintering effects of strong sunlight and hard frosts of high pressure can make wind-slab snow astonishingly hard to dig. A good snow saw is often the only effective way to deal with this type of snow.
Check out the size of the saw. It’s old fashioned but really does the job.
Many of the snow-hole sites are immediately adjacent to water courses. In addition, the snow pack often lasts well into the summer meaning there’s little opportunity for biological breakdown of human waste. If you do have to go you should do your business well away from the snow-hole site and far more preferably have some system to carry it out. Cairngorm Mountain’s Snow White Project has greatly improved the situation at the Cairngorm sites. All snow-holers coming to the Cairngorms are encouraged to use it.
The safety of a snow-holing in Scotland is often a reflected by the time it has taken to dig. I’m cautious about suggesting how long digging should take as it depends on a number of factors, not least the condition of the snow. From a “duty of care” perspective I feel a large communal snow-hole is much better than several separate small ones. I normally anticipate spending 4 to 5 hrs digging a 4 plus person snow-hole. I accept in soft snow conditions that this can possibly be shorter for a fit party of 2 each digging their own entrance.
With the vagaries of the winter weather, if done correctly Snow-holing is often the far safer option compared to a tented high camp in Scotland’s Winter Mountains.
* Andy holds the WML and IML awards and has over 20 years Mountain Leading experience. He has guided well over 30 commercial snow-holing trips in this time and although none of the mountaineering qualifications have a remit that covers snow-holing, he is one of the few guides deemed competent by HSE criteria of “relevant experience” to run snow-holing trips.
** British Antartic Survey helped in a BSc thesis. Available on request from andrew@scotmountainholidays.com
Medical references:
www.ncbi.nim.ni.gov/pubmed/18665947
www.ncbi.nim.ni.gov/pubmed/9340627
www.ncbi.nim.ni.gov/pubmed/8355417
www.ncbi.nim.ni.gov/pubmed/15265339
If you’re in the Highlands on a business trip, and have a few days to spare here’s an idea for a personalised tour we could put together for you and your group.
Mary Jane Shankel and her son, Josh, were over in Aberdeen with her husband, who was unfortunately working so he couldn’t enjoy the same freedom to explore as them. They contacted us and we put together the following tour for them which Mary Jane has reviewed on TripAdvisor.
This trip took place at the end of April 2015 so don’t be surprised to see snow on the ground for the hikes – it wasn’t too much of a shock for the Shankels as they had come over from Canada.
The timing of Mary Jane’s trip was tight so their first day started late (around 11am – due to the travel time from Aberdeen)
Day 1: Hiking in the Aviemore area: arrive at Fraoch Lodge on the train from Aberdeen, via Inverness to Aviemore station, where Mary Jane and her son were met by Andy in our VW Caravelle. Andy brought the 2 Canadians back to Fraoch Lodge where they changed into hiking gear and chatted to him about the route for the day, the gear they needed and then they made up a lunch packet and set out for a half-day hike in the Cairngorms.
Ascent of Meall a’Bhucaille.
Mary Jane and Josh enjoying some predator free hiking in Scotland. In Canada, there are bears, wolves etc – serious predators to worry about. Here in Scotland we just need to worry about the wee predators (midges and ticks). On a day like this in the Spring, even they are not around, so hassle free hiking.
Day 2: A pub, a castle and a hill walk: Mary Jane had proposed in her first email to us that ideally she would like to include a pub and a castle in with the hiking as it was to be her son’s first experience of Scotland. By including this visit to Perthshire (a short drive from Fraoch Lodge – less than 2 hours) Andy hit all these highlights.
Mary Jane and Josh outside Blair Castle, Perthshire. The Duke of Athol is the only person entitled to retain his own private army.
On top of the world – an ascent of Ben Vraikie, Perthshire. A prominent viewpoint above Pitlochry.
The final tick – a pub complete with own brew and a log fire. What more could you ask for at the end of a busy day of culture (castle) and hiking (Ben Vraikie). The whole bucket list in a nutshell courtesy of Scot Mountain Holdays.
Day 3: a sad farewell – heading back to Aberdeen.
Here’s what Mary Jane had to say in her 5 star review of the trip:
“Andy and Rebecca are the most fabulous hosts, they made us feel like we were old friends on a short visit. We packed in really, really full days of hiking and sight-seeing. Being short of time, Andy skillfully managed our wish list of 2 half day hikes, a tour of a Scottish Castle and a trip to a traditional pub. Andy’s breadth of knowledge seems unbounded; Scottish history, geology and ecology kept us tuned in to the beautiful landscape and people of Scotland. Topping off the day with Rebecca’s wonderful cooking and wandering through their organic garden made the trip a seem like we had found a little piece of heaven. Weeks later we are still talking about it and planning a return trip…a longer one this time!”
Mary Jane and Josh enjoyed a private guiding package with Scot Mountain Holidays. They had no transport themselves so were able to benefit from our transport as well as Andy’s local knowledge. On their own and on their first tour, they would not have been able to complete their tick list. It’s only a shame that Mary Jane’s husband was not able to join them. Perhaps on a future trip they can tempt him to explore more widely when he is not as busy with work issues.
If you are short of time and want to pack in as much as you can on your visit to the Highlands, please contact us for a quote. Our trips are most frequently based from our own home in the Cairngorms National Park, but we can work further afield. Based with us you can access a wide variety of top attractions: a distillery, Loch Ness, beautiful scenery, castles galore, historic sites and boundless hiking opportunities as well as wildlife spotting.
Hiking Vacations across the Highlands of Scotland
Adventure vacation in Scotland for all the family
In May 2015 we were asked to organise a trip for 2 days and 3 nights which had to end at the Craigellachie Hotel and needed to include a hike in the Cairngorms National Park.
We ran a tailor-made trip including a guided ascent of Ben Macdui, which was far more than could have been accomplished without Andy’s guidance. Even in May the temperatures on the high Cairngorm plateau are not much above freezing level. It is essential to wind proof clothing and plenty of warm layers. Fortunately Andy always has spare clothing to loan to walkers in his group and though his supply of hats may not be too flattering, at least they are warm.
On day 2: Diana and Ted walked through to Aviemore along theSpeyside Way, one of Scotland’s waymarked long distance routes. This was a contrasting walk with the previous day on a wide relatively level track facing the mountains they had been exploring the previous day. A wee bit of a warm down walk was needed after the exertions of the previous day.
On day 3: we had very limited time before meeting up with some of the wedding party at the Craigellachie Hotel for a private whisky tasting at the Macallan distillery. Fortunately we left promptly and headed straight out to Culloden Battlefield visitor information centre (Diana was anOutlander fan, keen to see the battle sight and experience some of the atmosphere).
We also hit the Speyside Cooperage to see the Coopers (who make the whisky barrels) at work. The Cooperage is only around the corner from the hotel, but would still have been a wee bit of a challenge to get to on their own.
Without the help of Scot Mountain Holidays, Diana and Ted may well not have been able to hike to the summit of Ben Macdui, despite their previous hiking experience in the States. They would also probably have needed to hire a car and may never have got to Culloden Battlefield.
Self-guided Mountain Biking breaks
Email us if you think we can help plan your vacation in Scotland – we can hit all the Highland hotspots and include some off the beaten track surprises you might not know about.
For inspiration check out our Pinterest board and our Flickr account.
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