Treading a line between walking and mountaineering, the Carn Mor Dearg Arete is an exhilarating ridge traverse amongst truly outstanding mountain scenery. It offers an infinitely more rewarding way to reach the summit of Ben Nevis than the tourist track, and if you save it for good weather, it will be a day you are unlikely to forget. When the first snows arrived in the Highlands in late October, I did what I suspect many other hillwalkers and climbers were doing - begged to the 'snow gods' that it would signal the start of a good winter. I spent several evenings excitedly flicking through maps and guidebooks, making plans and hoping for a better winter than last year.

The middle section of the ridge starts to feel a little more serious. The exposure increases, and you really need to be sure of your footwork

I have climbed Ben Nevis many times, by many of the buttresses and winter routes on the North face. I have traversed the Carn Mor Dearg Arete onto 'the Ben' multiple times also, but I surprised myself with the realisation that I had never actually done it in full winter conditions.

With a forecast for a cold November day, and with a good covering of snow across the Highlands, I headed to Fort William to rectify this.

I have always enjoyed getting up onto the tops for sunrise. I like to watch the play of light over the landscape, and I love the experience of walking in through the dark. It was extremely cold when I left the car at the north face carpark. A layer of freezing fog was filling the glens, and frozen trees sparkled in the light of my headtorch as I started the steep approach to Carn Mor Dearg.

It was not long before I reached the first challenge of the day. Several days of hard frost had frozen the ground solid, and I was confronted by an area of glassy ice covering large parts of the hillside. I had rarely seen anything like it so early in the winter before. It took me a while to find a safe way through, and I continued towards the snow line.

Eager to reach the summit of Carn Mor Dearg before sunrise, I was moving fast but had to stop at least once to photograph Ben Nevis illuminated by moonlight. It was a perfect winter scene, with occasional shooting stars streaking across the sky. I was already having a memorable day, and dawn had yet to break.

Carn Mor Dearg has arguably one of the best summit views of any Munro. Looking straight onto the North face of Ben Nevis, this is a view of almost Alpine character. The areté is a striking feature to behold - a graceful curve leading off into the distance, leading straight towards the highest summit in the UK. I spent a while taking photographs, and bumped into mountain artist Jamie Hageman who was also out enjoying the wonderful early season conditions.

Ice axe in hand and crampons fitted, I set off along the arete. To begin with it is an easy walking descent, but is isn't long until the first scrambling is met. The ridge is largely made up of balanced slabs and boulders. Some of these can be avoided by traversing around, but this would be missing the most enjoyable sections.

The consistently cold conditions had left the snow largely unchanged, so it was mainly fluffy powder. Whilst lovely to look at, it was certainly more challenging conditions than if there had been firm snow. I decided to take the ridge directly as possible, taking in multiple short steps and downclimbs. There were always axe placements to be found when I needed one. The middle section of the ridge starts to feel a little more serious. The exposure increases, and you really need to be sure of your foot-work. Whilst traversing around the most exposed sections would have been possible, it would have probably been more hazardous than taking the ridge direct in the conditions.

Half way along the areté, and it really had started to feel like a day up high in the Alps. I had started to overheat in all my layers, and the sun was exceptionally bright for November. There was absolutely no wind. Indeed, it was so quiet that I could easily hear climbers talking outside the CIC hut, over a kilometre away in the corrie. A slight haze hung over the view towards Glen Coe and the Southern Highlands, whilst a broken cloud inversion covered Fort William and the Great Glen.

It had been quite a long, involved descent to the lowest point of the areté at 1058 metres. From here the ridge changes character slightly, as you begin the long ascent towards Ben Nevis. There were more exposed steps and slabs to negotiate as I climbed - never hard, but all of them requiring concentration. The view of the North face of Ben Nevis had been changing constantly throughout, and now I could start to pick out climbers enjoying the early season conditions on the cliffs.

A substantial cairn marks the end of the arete, and the technical difficulties. This is where the strenuous part begins, however. The final 200m ascent to the summit plateau of Ben Nevis feels like a tiring slog after the excitement of the ridge. It is bouldery, slightly loose ground, and I was glad to be able to follow the deep footprints of someone who had ascended this way the day before.

I have stood on the summit of Ben Nevis around 30 times, but this day was up there with the best of them. Here, at the highest point in the UK, it is remarkable how extensive the views are. Over 50 miles away to the northeast, the Cairngorm plateau looked impossibly close, as did the Paps of Jura to the southwest. There were only a few other people on the summit - a far cry from the crowds found here daily during the summer months. I lingered for long enough to take in the view, before starting the long descent down the tourist route.

Some mountain days are worth keeping back for years if it means getting them in perfect weather. The CMD Arete is one of them. Whether it's your first winter Grade I, or whether you are an accomplished winter mountaineer, this is without question one of the greatest mountain routes in the UK.

• Grade - I (Winter)
• Length - 17.5 km
• Ascent - 1506m
• Time - 9 to 12 hours
• Munros - Carn Mor Dearg, Ben Nevis
• Start point - Ben Nevis North face carpark NN144763
• Public transport - Some buses from Fort William towards Spean Bridge will stop at Torlundy on request.
• Route notes - A long, strenuous mountain day taking in two of the highest Munros in Scotland. The arete is over 1km of exposed Grade I winter mountaineering. The route is possible under any snow conditions, but overall difficulty will depend on the level of snow build-up. Winter conditions on the route can vary between lightly iced slabs and a pure snow ridge. The route is strongly recommended against during strong winds.
• Similar routes - Crib Goch (Snowdonia), Striding Edge (Lake District).
• Next steps - Beinn Alligin Traverse (Grade I), Liathach Traverse (Grade II).
• For the super fit - The Lochaber Traverse takes in the entire Grey Corries ridge, Aonach Beag and Aonach Mor, before finishing up the CMD Arete to Ben Nevis. One of the best, and most strenuous, winter mountaineering routes in the UK.

About James Roddie

James Roddie is an award-winning professional photographer and writer specialising in the wild places and wildlife of the Scottish Highlands. He is an active hillwalker, climber and caver based near Inverness. James runs outdoor photography workshops throughout the Scottish Highlands, and is a regular contributor to some of the UK's most prominent outdoors publications.

For more of his images and writing see www.jamesroddie.com