What is required for good winter conditions is at least five days of at least minus 5 at night with daytime temperature hovering about +3. Two further requirements to create good conditions are a good freeve prior to the first snow dump to allow the turf to freeze. It is quite rare for Donegal to get several big dumps of snow which create a complex snow pack. It is much a more regular occurrence for Donegal to get one large snow dump and then consolidation occurs to this single snow mass.
For more information check the Donegal Winter Climbers guidebook, Donegal Winter Climbing.
Winter Climbing in Donegal Film
Anyways, when winter does play ball in Donegal the mountains are transformed into a winter mountaineering playground. The north faces of Slieve Snaght, the Poison Glen, Errigal and Muckish being the prime winter climbing venues. These faces are predominantly very wet places during the summer months with this seepage in the winter months providing the perfect amount of water for good ice build up.
Below are a few wintery pictures of Donegals mountains over the past few years, every winter has been very different from the previous year. Some years there is an abundance of snow and very little freezing temperatures and other years it freezes so hard and quick that no snow falls and streams freeze at source and no ice cascades form.
Errigal from Slieve Snaght
The above picture shows the view from the summit of Slieve Snaght looking north towards Errigal. The gully in the foreground contains a shade over 6 meters of snow drift. We attempted to sleep the night in a snow hole, which took hours to dig out, alas the thaw came a few hours earlier and the roof collapsed as the sun set. We walked home off the hills in the dark.
Looking across the Poison Glen to Slieve Snaght
From the summit of Maumlack looking across the Poison Glen to Slieve Snaght, the alpine faces of the Poison Glen were in pristine winter condition with near 1000ft of compact néve in the gullies and the two falls transformed into near complete multi tiered cascades.
The Aghlas from Dooish Summit
Grogan Mor Plateau
Ice climbing on Muckish
Errigal above very dense cloud
Sunrise walking on winter mountains