Avalanche forecasting and Milk Delivering on Ben Nevis

Looking towards the Orion face area.

Looking up into Coire na Ciste.

Some essential supplies that I delivered to the CIC hut today, 4 and a bit litres semi-skimmed milk, 8 cans of coke, and a bottle of cheap Irish whiskey.

I was up on Ben nevis today. Mountain conditions were generally pretty good, with climbers spotted on Tower Ridge, Point Five Gully, Italian climb and No. 3 Gully Buttress. There are also quite a few short but nice looking icefalls below Carn Dearg Buttress (where we saw at least one team) and in the little gullies which lead up into Coire an Ciste. However, there is a few patches of slab about. Remember that a brief definition of a moderate hazard (which it is at the moment) is "Natural Avalanches unlikely. Human triggered avalanches possible", so don't assume that just because the hazard is "only" moderate, you can wander safely anywhere and everywhere on the hill with no risk triggering an avalanche.

I also took the chance to delivered some essential supplies for Dave and Andy who are staying at the CIC hut, and are involved in the Smith-Marshal project for the Fort William Mountain festival this weekend. We spotted them up on Minus Three Gully today.

Cracking underfoot

Some good example of cracking underfoot was observed today. When the snow is doing this on relatively gentle slopes, then steep slope covered in windslab are best avoided.

Under a threatening sky.

Looking over towards Ben Nevis and Carn Mor Dearg under a threatening sky.

Not very much ice on the north face of Aonach Beag, there has not been the freeze thaw cycles required to build the ice at this level so far this year.

A large and threatening cornice lurking at the top of easy gully at the moment.

Looking south across Coire an Lochan.

The snow is here

Looking towards the summit hut and top of the summit tow. It had just started snowing up there at that point.

It started snowing on Aonach Mor just before midday, and has been snowing pretty steadily since then. The winds were not super strong so the snow was quite soft. I think that the skiing could be pretty good when the visibility clears up. However, other than on exposed locations, the walking could be pretty hard going.

Now and then.

It was quite cloudy on the top of Aonach Mor today, so no great pictures today. Through the course of the winter we see significant changes in snow cover. In certain areas the snow builds up to great depths. When standing at the top of, for example, Easy Gully, I often wonder just how much snow there is under my feet. I am still not sure, but thought I would put on some pictures of the top of the East Face taken recently (still quite early in the season), to compare with some taken in the summer to give an indication of snow depth, and how the character of the place changes.

Climbers above central buttress last week.
The top of central buttress is late August. Note firstly that the fence posts are just back from the change in angle, and secondly there are a couple of patches of snow still visible in the background. Last summer (2009) all the snow melted on Aonach Mor during the summer, but a patch did survive over on Aonach Beag. The previous summer 2008, patches of snow survived all summer on both Aonach Mor and Aonach Beag.

The top of Easy Gully yesterday (Sat 30th).

The top of easy gully in summer (during a rare summer ascent of the gully).

Ben Nevis

Some pictures from Ben Nevis today.

With a freezing level of 1800 metres and moderate winds forecast, it's not going to look like this tomorrow I am afraid.

Poor visibility weekend

It was a weekend of low visibility on the tops, so no nice photo's I am afraid. It did clear up today after I had got down from the hill, so here is one of Aonach Mor taken this afternoon. Snow cover is generally pretty good at higher levels, with the ski touring being good if the visibility would clear up. There is also some good climbing on Ben Nevis. With a thaw, followed by a freeze and hopefully some more snow forecast for later in the week, hopefully conditions will improve.

Pictures from today

The cuckoo hut at the top of the ski area was looking quite frosted today.

Climbers at the top of Left Twin. As can been seen the top of many routes are quite corniced at the moment. However, there is often a break in the cornice just beyond where the figure are that can allows an easy way to top out from Left Twin and many of the routes on Central Buttress.

Soft cornices.

Last nights wind and snow has formed some large and fragile cornices. These are prone to collapse both spontaneously, or if disturbed, and can easily release the windslab on the slope below. Unfortunately the light was very flat, and you can't see much in any of the pictures that I took of the cornices. However, the picture shows the side/crown wall of a cornice triggered slab avalanche (notice the rope, I approached this safely via a short abseil from the top). Although this was not a large avalanche in the grand scheme of things (the release area was about 8m across), it would have easily have sent you tumbling should you have been climbing/walking below. Another such crown wall was just visible further along.

If climbing in these conditions it is wise to consider what is above you what is above your route, and avoid gullies with big cornices/areas of windslab above. With a bit of consideration and forward planning (some local knowledge helps as well though) routes which are safe from such objective dangers can almost always be found.

Avalanche on Aonach Mor

On the way up Aonach Mor this morning we heard reports of a "wee slide" being triggered on the West Face at the lowly altitude of about 600 metres. We had been planning to head to that sort of area anyway, so we decided to go and investigate. What we found was a hard slab avalanche had occurred. It was about 50 metres wide, and had run about 200 metres down the hill side. The crown wall reached a maximum depth over a metre, and was 50cm to 1 metre deep from most of it's length. A bit bigger than a "wee slide" I thought. The avalanche had run on a deep and particularly hard layer of small rounded crystals. Today's snow profile is a profile of the crown wall.

Looking south to where the crown wall height was at it's greatest (about 110cm). The first two pictures were taken from the location of the figure in the third picture.

Investigating the crown wall.

Looking back north along the crown wall, it is not too clear but it continues beyond where the figure is. This photo was taken from just below where the figure is in the first picture.

Blowing snow.

Even a seemingly uniform layer of snow will contain many mirco-layers, created by constantly changing conditions as the snow was deposited. Usually these are not too evident, but the strong winds blasting this block of windslab that I dug up really made this micro-layering visible (the horizontal bands).

There was a strong wind on Aonach Mor today. It was very variable in directions, redistributing the existing snow around the mountain. This means that there are pockets of slab on many aspects.

Shearing layers

Three very clean shears came out today when doing a tap test on at the top of the West Face of Aonach Mor. The lollipop sticks were included to mark layers shear, although they are pretty obvious in this case. I am not sure whether you will be able to read scale on the ruler, but in this test these shears occurred at a depth of 12, 20 and 33 cm. This photo was taken on a low angled (about 15 degree) slope with a Westerly aspect. I would be very wary of going onto any steep, snowy slopes with this aspect at the moment.

Looking into Coire an Lochan today. A fair bit of snow on the East Face of Aonach Mor as well.

Deep drifts

Keith looking at one of the big drifts in the summit plateau at Aonach Mor. There are several of these deposits on the summit plateau formed from the wind erosion from the big easterly corries. This one is almost 2 metres deep

More good weather

Another beautiful day in Lochaber!

Facets.

The cold and generally settled conditions have continued in Lochaber. Normally snowpack stability will improve during settled periods. However, due to the consistant low temperatures of late, a strong temperature gradient has developed within the snowpack. This has caused a process called faceting to occur within certain layers. This process is due to vapour transfer within the snowpack and causes the crystals to become angular in shape, and have a sugary consistancy. These layers are very weak, and in many locations are covered by a layer of windslab.

In the picture a crack shoots out from my feet (a sign of poor stability) on an easy angled slope at the top of the West Face of Aonach Mor. Very weakly bonded areas of windslab were also observed on the East Face. Although no spontaneous avalanches are happening at the moment, there is potential to trigger avalanches on slopes of almost any aspect.

Have a good new year and be careful folks.

Blair

Cold and settled

Conditions have been cold and settled for a few days now. Great for the festive holidays. Here are some pictures from on and around Aonach Mor over the past few days.

Looking over to Carn Mor Dearg and Ben Nevis today.

The crags in Coire an Lochan are pretty buried. I think the routes here would be pretty hard work with a lot of clearing required.

There are a few cornices around as well.

Surface hoar forming in the cold, settled conditions (for scale the larger grid on the crystal card is 3mm). These sparkly little crystals are the cause of many avalanches in the Alps and North America, where they get buried by subsequent snow falls, and become a weak layer/sliding surface. They are less common in Scotland's maritime climate, but now they have formed in some locations they could easily become significant if we get a large snowfall before they are destroyed by either high winds or a thaw.

Very quiet up the Ben today with only 2 parties visible: Point five and Castle Ridge.

Underfoot its still deepish unconsolidated snow

Spot the climber in Point Five today

Happy Christmas

Happy Christmas from snowy Glen Nevis looking up towards Meall Cumhann and the West face of Aonach Beag

A new Season

Is the weather about to clear up.....

Well it has been a wintery start to the avalanche forecasting season. The past few days have been cold, with summit temperatures of around minus five and fresh snow down to sea level. For a short time this morning it looked like it was about to clear up on Aonach Mor, but suddenly the wind got up and it started snowing. At the summit hut I met two climbers who had originally planned to descend Easy Gully into Coire an Lochan. However, with a fair bit of soft windslab about, and the poor visibility, they sensibly decided to head over to the West Face (often a safer bet when there is a substantial avalanche hazard in Coire an Lochan).

Discussing options at the summit hut

Heading away from the top of Coire an Lochan in some wild weather.

Just about the end

Filming for Countryfile. Showing Julia Bradbury that avalanche forecasting is not as glamourous as some may believe.

Well it's just about the end of the season here in Lochaber (the last report will be published on Friday) and this will probabely be the last blog post.
During the past few days Countryfile been doing some some filming in the area, including the work of the avalanche forecasters. This will shown next Sunday at 7pm on BBC1.
Also on Sunday there will be a Seminar on the Provision of Avalanche Forecasting in Scotland at Glenmore Lodge. More information can be found on the SAIS website.
See you next winter.
Blair

Still Plenty of Snow in Lochaber

There is still a fair bit of snow about on high East facing aspects in Lochaber at the moment.

Boarding down Summit Gully. Conditions looked good.

Still some large cornices about.

It was so nice that pac-man quit his 80's computer game, joined up with spider man (on the tow) and came up with some boarding.

The Aonach Mor Crevasse.

Debris from an avalanche almost down to the loch.

It was mild, but thankfully quite dry on Aonach Mor today. Debris from an avalanche, which probabely released on Wednseday night or Thursday, was observed almost down to the lochan of Coire an Lochan. The crown wall could be seen at the top of Easy Gully. This was a vertical drop of about 350 metres.

Taken from standing in a rather deep crack in the snow. The overhanging natural of the walls meant that it felt about grade VI to get out of.

In the mild conditions some large creep/slump cracks are starting to form. This one was covered by a soft layer of snow until being "discovered" my assistant, it gave her a bit of a shock.
Blair

Lots of snow high up.

Lots of little sluffs in Coire an Lochan, probabley from yesterdays snowfall.

Still a few chunky cornices about. I would be very wary about being below one of these on a mild day.

Firstly sorry about the long time period since we last blogged, out camera got misplaced for a while. Have got it back now. Although it may not appear this way from the glens, there is still plenty of snow about high up in Lochaber. Conditions on many of the easy and mid grade gullies and ice routes high on the Ben and Aonach Mor are probabley quite good, if a little soft in places, at the moment. What's more the crags are very quite (there was nobody climbing in Coire an Lochan of Aonach Mor today) and there is loads of daylight so you don't even have to get up that early. Snow stability has generally been pretty good recently, but this can change rapidly if we have a big dump of fresh snow. Also be wary of cornice collapse and ice fall on those mild days.
Blair