FROM WINTER SERENITY TO WHITE-OUT IN THE BLINK OF AN EYE

A LANDSCAPE of unspoiled white as far as the eye could see sparkling with the early sun starting to spill over the high cols, an illumination which seemed to bounce off the glass surface of Loch a' Bhraoin.

The contrast between the peaks and the shadowed glen was stark. The tops were reflecting blinding light, while patches of ice glistened through the blanket down below, every tree, every blade of grass frozen in place as though caught in the eyeline of an icy gorgon.

Sitting in the warmth of the car, this burgeoning brilliance suggested a perfect winter mountain day. Once outside, the true nature of the conditions was immediately and brutally apparent. The forecast temperature was minus ten. No real surprise there was no one else around. The lack of wind was a plus factor, though it was a struggle to tie up the boots and fit crampons with fingers already numb, a further battle to pull on gloves.

The sun came with me as I moved smartly on the track along the side of the loch, a walk of constant reflection in the water of the surrounding high peaks which served to warm the emotions if not the extremities.

I was heading for Creag Rainich, a humble Corbett in the midst of giants. There's no great soaring faces here, no dramatic crags – and no definitive route. It usually involves a pathless ascent on gentle grassy slopes with a smattering of boggy sections to dodge round.

Even if there had been a path, it wouldn't have mattered. This would be a constant slog through deep soft snow, weaving and winding to find the easiest passage, every step an adventure. It's hard going in these conditions and book times go out the window.

As soon as I left the track and took to the open hill the crampons had to come off, their effectiveness diminished by the depth of snow, more of a hinderance than an aid. One pair of gloves was also ditched, the upward push in the sun now proving warm work.

By the time I reached the intervening knoll of Meall Dubh, I had been going nearly three hours. The main summit wasn't too far away, but that short distance was through the deepest drifts and what would normally take 15 minutes to skip up took nearly three times that long with an exhausting amount of post-holing.

Still, at least I reckoned I could make a fast descent to get down before dark by retracing my steps along the obvious path I had ploughed. But as is so often the case in winter, the situation can deteriorate in a heartbeat.

The sky had been growing darker as I touched the summit trig, the sun becoming a pale imitation of its earlier presence. The surroundings had also dulled considerably, presenting a more menacing facade. But the biggest hint that things were about to turn bad was the view north to mighty An Teallach.

For most of the ascent it had been playing as a shimmering fairytale castle on the horizon, spires and peaks glowing brilliant white. Now it was rapidly turning into a vision of Mordor, towering, roiling jet-black clouds pouring over the ramparts.

It was heading my way and I should have made an immediate exit but it was proving hypnotic, fascinating to watch as the darkness barreled its way towards my standpoint. I eventually tore myself away and got as far as the first col before I was engulfed in its fury.

The pathway I had created on the way up was already disappearing. It only took a few more seconds before I couldn't see a thing, couldn't tell where I had come from or where I was going. If this wasn't a white-out, it was the closest thing to it.

I tried to stick to my approach line but had a few minor slips and falls, impossible to tell where there were dips in the ground, the next step forward always cloaked in deception. The concern was that one of these falls would result in an injury: a twisted ankle, a jarred knee – no matter how minor, it would be a major problem up here. I made the decision to take a reading and head straight down, ignoring the ascent route in favour of finding the shortest possible route to reach the track. There were no hidden crags, just grass slopes. It would mean a few extra miles on the walk-out but it would be safer, more certain.

About halfway down, and with the return of a little visibility, I reached a fence running east to west over a hollow. The instinct was to follow it to the right, but the compass was telling me to cross it and keep heading south. Always trust the compass.

It's strange how your priorities change in situations like this. My first was to get off the hill safely and reach the track on the lochside. Once that was achieved, I turned my attention to worrying as to whether the car would still be there when I got back. When I had set off that morning, it was the only one there. That concern eased about a half-mile from the finish when I could spot its shape through the driving snow. Still standing alone – I hadn't seen anyone else all day. The next thought: would it start after sitting in those bitter temperatures for hours? First time, no problem.

So the focus switched to the next possible snag: would I be able to drive back to base near Ullapool? The road was under deep snow cover with just a few slushy wheel tracks showing, and the westward section was already closed. But I was heading the other way, and it was still passable with caution.

A day when serenity turned to white-out in the blink of an eye, a day when there were so many times something could have gone pear-shaped. Winter in the mountains is magnificent, but it pays to be prepared to face whatever the elements throw at you.