Winter climbing, a matter of style. Part two, mixed climbing.

So far this winter we have only had a couple of days of winter climbing. It has not been very cold and we have had little snow. Next week might turn out to be a little bit colder. There is a layer of snow on the tops right now, and at the end of the week it could get properly cold for the first time. So, here's what to look out for when it gets cold again. We will need to wait a little longer for the different types of ice climb we enjoy in Scotland

Mixed climbing has always been pursued in Scotland but it has become more popular in the last couple of decades. Whereas in ice climbing there is a limit to how hard it gets due to the nature of how ice forms, in mixed climbing there is virtually no limit. What is possibly the hardest naturally protected winter climb in the world is found on Ben Nevis; Anubis, climbed by Dave MacLeod and repeated twice since. Greg Boswell McInnes made the third ascent in 2019, a particularly poor winter for climbing. This illustrates the attraction of mixed climbing, that good climbing conditions can form quickly and there is ample opportunity for a challenging climb!

In the same way as with ice climbing, judging the nature of the climbing conditions is a tricky job and one that demands dedication, time and many attempts, both successful and unsuccessful. Once you know what to look for and how the recent weather affects the climbs, you will be able to make better decisions.

Thick rime on the Gargoyle Cracks.

Mixed climbs need to be white and frozen to be in generally acceptable condition. Dry tooling is not acceptable on Scottish crags away from some low level training crags. In the mountains, the crag needs to be be wintry in appearance, white with snow or rime and frozen. This is the ethical approach that has developed over many years and is peculiar to Scotland. Many foreign climbers are baffled by these restrictions, but we abide by them to maintain the quality of experience and so that we are all playing by the same rules. Waiting until the crag is properly frozen also protects turf from excessive damage.

Different types of mixed climbs might be termed snowed up rock climbs, turfy mixed climbs or true mixed climbs on which a mixture of rock, turf, snow and ice is experienced. All of these types of route need to be well frozen to give good climbing.

Rime ice crystals on Curved Ridge.

Snowed Up Rock Climbs.

Snowed up rock climbs can freeze first due to being mostly made of solid rock. Even so, blocks, chockstones and flakes need to be frozen in place, and this takes a couple of weeks of sub-zero conditions at the start of the winter. They often make a good choice for the first climbs of the winter season because they are first to freeze, don’t require any thaw freeze cycles and can offer reasonable protection.

“Snowed up rock climb” is actually an unhelpful name for this style of climb. It is rime that is more effective at making the climb white and that will provide better climbing conditions. Rime is a type of ice crystal that grows on any surface exposed to humid air being blown onto it in a sub-zero temperature. It is often seen on fence posts and, perhaps confusingly, grows into the wind. So, you need a wind blowing cloud on to the crag and the temperature to be below zero. No snow fall is required at all. After a westerly gale, choose a crag that faces west and has been in the cloud.

The best conditions in which I’ve climbed snowed up rock have included really well frozen rocks and a light rime of a couple of centimetres that is easily brushed away to reveal (hopefully) cracks and ledges underneath. The crag was totally white at the start of the day but the climbs were brushed free of rime by climbers on various routes.

Delicate dry rime can fall off the crag in a strong wind and is likely to fall off in very dry, cold air. This means that the crag can be white one day but black the next day despite the temperature staying below zero. Once the crag is out of the cloud the rime will start to deteriorate. Sunshine will also strip rime from the rocks faster than you can climb them!

Donald King making the first winter ascent of Engineers Crack in perfect winter condition.

However, rime can grow to be a metre deep and turns very icy if it experiences thaw freeze cycles. The summit observatory ruins on Ben Nevis often have incredibly thick rime ice all over them in March that has built up over the previous three or four months and survived many thaw freeze cycles. This is not good to find if you want to climb the rock underneath. In thick, icy rime, it can be a monumental struggle to clear the rime off the rocks for the whole pitch.

Thaw freeze cycles will also create dribbles of water that run into cracks and refreeze. Iced up cracks are a problem; finding pick placements can be very hard and uncovering protection incredibly tiring. Snowed up rock climbs are best early in the season when the cracks are still clear of ice and the rime is light and fluffy.

Snow fall can also make a crag white in appearance. Cold, dry snow will not stick to the rocks. It will pile up on ledges making the crag look white from above but not from below. If the snow is a bit wet (this happens when the temperature is at or not far below freezing) it can stick to the rocks and make the whole crag go white. This wet snow can also freeze into an unhelpful icy crust which is hard to clear from the rocks when you are climbing.

Some snow on the ledges is very often a helpful thing to have on all mixed climbs, including snowed up mixed routes, especially once this snow has transformed into solid snow ice after a freeze thaw cycle.

Curved Ridge on Buachaille Etive Mor, Crest Route on Stob Coire nan Lochan, Slab Route and Gargoyle Wall on Ben Nevis are all excellent snowed up rock climbs.

Louisa Reynolds climbing Taliballan in dry, turfy mixed climbing conditions.

Turfy Mixed Climbs.

Turf freezes slowly. Small tufts of turf freeze first and freeze most quickly when they are exposed to a cold wind. Wind chill affects the crag in the same way as it affects us when we are exposed to the wind. Big patches of turf can take many weeks to freeze properly but can be damaged or even completely removed from the crag if they are climbed over before they are frozen.

However, once properly frozen, turf will stay frozen through some quite substantial periods of thaw. It will hold water in a thaw which will dribble down below the turf and freeze into ice of one sort or another in the refreeze. So, turfy mixed climbs can become really quite icy over the course of the winter. There is nothing more satisfying than placing a pick in a solid, icy lump of turf!

Turf commonly holds snow on top of it which is transformed into snow ice with thaw freeze cycles. So, turfy mixed climbs quite often turn into true mixed climbs over the course of a good winter, with a mixture of turf, rock, ice and snow ice.

Tommy Kelly at the same place on Taliballan with a lot more ice.

Turfy mixed climbs, like any mixed climbs, should look wintry and white. Rime and snow should cover the rocks. There is an argument that only the turf needs to be frozen and icy, that the rocks don’t need to be white as well since they are not used for the climbing. This is mostly the case on sandstone crags found in the far North West and is also a matter of opinion. It would be easier to say that all mixed climbs need to be white and wintry in appearance with the rocks covered in rime or snow.

Morwind is a very good turfy mixed climb on Aonach Mor which changes in character to a true mixed climb and can actually form so much snow ice that you don’t need to use the rock at all. Thompsons Route on Ben Nevis is the same but it requires some snow ice to be formed before it is fun to climb whereas Morwind is good fun as a turfy mixed climb with no snow ice. Taliballan on Stob Coire nan Laoigh is a wonderful turfy mixed climb that turns into a brilliant true mixed climb with varying amounts of ice and snow ice depending on the nature of the storms of the winter.

Kenny Grant climbing Tilt.

True Mixed Climbs.

Those routes that demand a specific combination of snowed up rock, frozen turf and ice of various kinds are true mixed climbs. Being so specific in nature and requiring the perfect combination of factors in the weather over the course of a couple of months, these are highly sought after climbs.

Gemini and The Shield Direct on Ben Nevis are perhaps the best examples. The first few pitches are on steep ice formed by melting snow patches above providing water to freeze into cascade ice. This is followed by a mixture of snowed up rock, snow ice and little bits of turf in the upper pitches.

So, now you know what is required to form good mixed climbing conditions, hopefully you will have more success in finding them. You still need to know or to assess the nature of each climb (if it is a snowed up rock route, turfy or true mixed climb) to determine whether it will be a good choice on any given day of climbing. For the moment, you'll need to work this out by yourself.

Bob Johnson enjoying the delights of the true mixed climb Lost The Place.