The NW ridge of Koskulak is long and demanding. You are a long time on high altitude and the snow can be deep. The area is sometimes hit by sudden and fierce blizzards and the temperature amplitude can range from -20 to +40.
In other words it's like any other climb of a 7000m peak.
The above said, it's one of the easiest of that altitude. There's no real technical difficulties and the route is straight forward and obvious.
The altitude gain from BC to the summit is roughly 2600m (4400-7000m), depending a bit on where you pitch our tent.
One great thing about the climb is that you can put your BC on grass, close to a little glacial stream. That's not so common for 7000m peaks, where you many times have to camp on cold and uncomfortable moraines.
The traverse and the crevasse section
China - Kashgar - Subashi or Karakol - Ulugrabat Daban (pass) - Koskulak BC.
For the long version on how to get there, have a look at the getting there section on the main page.
Choose your BC
"The grassy BC"
Organizers may take you to the foot of the glacier quite far away from the place where I set my BC. The former isn't a nice place, but the closeness to the start of the route from there is slightly closer than the walk from "my BC" to the foot of the mountain. In time the difference is about 15 minutes, counting from your tent until you reach the first steeper slope of the peak.
I think the positive aspect of having a nice place as your base, instead of a miserable one on a cold moraine far outweighs the fact that it takes you 15 minutes to walk to the peak. The route from my BC is also more direct and mostly on snow. The other BC is along a long, boring ridge on horrible scree and the gradient is much lower on that one as well.
The other aspect which can be brought forward about the location of my BC is that you either have to traverse over the face to be able to camp on rocks at about 5300m, or you have to camp on snow. If you don't really care what surface you camp on, then the choice is obvious - go for the spot where I camped.
How do you find this spot?
Follow the moraine which comes from the Kalaxong glacier and walk along it until you find two small ponds. Next to them there's a well protected bowl which is like custom made for camping. Grass and a small stream cuts straight through the meadow. There are small tracks made by domestic animals leading to this place from the lower parts of the valley.
I should add I've tried both BCs and routes to C1 as I started from my own private BC, but was forced to move to the other as the persons on my permit climbed from that place. Grrr.
The route - NW ridge
1. To the southern BC, located at the end of the glacier. On a moraine. Not that good and the ridge from it up to C1 is boring, axing and long on loose gravel and rock.
2. Site for C1. You can find flat enough places where the line is green. If lucky even old platforms from earlier expeditions.
Note: If you have sharp eyes you may see a tent in the middle of the snowfield at about 5500-5550m. A three person team had chosen to camp there.
3. To the northern BC, located on a grassy spot next to a stream and two ponds. Well sheltered from the wind.
4. I saw traces of a camp here on the last gravel section. May be an alternative.
5. The two alternative routes meet. From here on the route is a little bit up and down and there are many places where you can pitch a tent.
6. The traverse. This section may change from year to year.
7. Navigation between crevasses. Also this section may be different next year. If the second crevasse gets much bigger it'll split the ridge in two and then the long SW ridge may be a more feasible alternative.
8. Summit, 7028m somewhere up there in the clouds.
9. Central icefall.
10. The only difficult section on the long SW ridge route.
There are no "set camps" on Koskulak. The mountain has many spots flat enough for pitching a tent.
This description is about the route from the grassy BC described above.
Head for the left hand side of the large snow field. The easiest is to either walk along Kalaxong glacier or in the middle of the grassy plateau.
When hitting the snow, you can either head straight up to a suitable place to put your C1, or you can make a slow traverse to the right edge of the NW ridge, where you'll find rock to camp on. The advantage to camp on the latter side is you may have water in a little melt off stream from the central glacier. You may also find it more comfortable to camp on rock. There are lots of places where you can dig out a platform on the rocky part of the ridge.
There may be old platforms in between 5200-5400m and unfortunately also garbage from any of the Russian expeditions in 2005. Great climbers, but someone should give them a lesson in what you're supposed to leave on a mountain and what to bring back down. Metal tins is a great example of the latter, plastic is another.
C1 to C2
If you choose to stay on the rocks on the south side of the snowfield, head upwards along the path of least resistance until you arrive on flatter ground. You then see a little pointed highpoint ahead. Pass this it on the left, as there are crevasses and steeper on the right.
The route is very flat on this section and you don't gain much altitude. Good for putting a camp. Approx. 5700-5800m.
If you have chosen to go from the grassy BC further north, you have no trouble to find a good line up to the flatter part. Just head straight up where you please.
After the flat part, the route is undulating a bit. Stay clear of both the edge to the left/north and the extreme right/south. There may be fresh snow hiding the cornice on your left and there are crevasses, especially one huge, to your right closer to the central icefall.
It once again gets flatter and you see the traverse section and the "crux" above. If you have climbed on skis or snow shoes you may want to take them off here and attach them to your backpack and put on crampons for the traverse. When I was here the snow was fine, but I can imagine there's a slight risk of the snow sliding down to the right creating a short but potentially disastrous avalanche which will bring you down to the glacier below.
IF you feel uncomfortable to traverse on a 45 degree slope, with a large drop - rope up here. Traverse the ridge until the route drops a bit. Here you have to navigate around a crevasse. Keep left of the first one, but don't go too far left - the cornice is large.
The second crevasse is almost splitting the ridge in half and the conditions can probably vary a lot from year to year. I's a bit steeper here. Climb up to a little plateau. This is were some teams choose to put C2. It's a good choice as you have now passed the crux and only have about 600 vertical meters to the summit.
As Koskulak is so flat you have other camp spot alternatives along the route. I saw traces of old camps both on the flat part at about 5800m and just before the traverse section at roughly 6200m.
C2 to summit
The rest of the way up to 7028m is a long flat slog in snow. Snow shoes or skis may prove to be essential. The summit plateau is very flat, but when close it's no doubt about where the highest point is located.
Note: I damaged one of my eyes on a cut contact lens and had to go down to Kashgar for treatment, so I didn't summit the peak. The last section (C2-summit) was provided by a German climber who summited the peak. He said it wasn't much to say about the route at all over the last crevasse.
GearClothing for extreme cold. Even in the warmest season it can get awfully cold on 7000m.
Footwear which keeps you warm. In this case that means plastic boots or warm single layer boots backed up with super gaiters.
Walking sticks, preferably with big baskets.
Snow shoes or skis.
Tough camping gear, which includes a really warm down bag, a sturdy tent etc.
Good stuff for sun protection (Sun glasses, sun block etc).
GPS and/or altimeter.
Harness and rope etc. if you want to play it safe with the crevasses and the traverse.
You may want to bring a bivy bag for stashing gear in, or for emergency situations.
Crampons, if the traverse or the short steep part over it is icy.
The below gear is not necessary for climbing Koskulak, but can come in handy for crevasse rescue.
Snow stakes and/or a deadman.
LinksClimbing links that may be useful.
Two good photos, with the routes.
The routes of Koskulak.
Short expedition reports on Risk.ru.
Report from Shamalo's teams ascent of Koskulak.
MAI - a Russian climbing club's page about exploits in the area. In Russian.
If you want a way harder route on Koskulak, check out the route Alexei and Valery took in 2005.