Travel advisory - Snowstorms in Annapurna National Park

#9 if your friend is at Chhomrong, then he is not heading to Thorung La (or had already passed Thorung La days ago) - it is in a different direction. There will have no snow in Chhomromg. He might be heading to ABC, which, due to the weather situation, may also have snow higher up at MBCand ABC.

Thanks Anpijola, I think he may have been heading to Annapurna base camp so thankfully well away from Thorung La. Did that area avoid the severe weather?

Sorry just read your post properly :) re. ABC.

skyline1 #4:

Your question is rather difficult to answer categorically but I will give it a go.

The four things that generally remove snow are sun, rain, wind, and avalanche. Sun obviously melts snow which runs away as water. This can happen quite quickly, even for a 1m fall, if the slope receives full sun. Rain can probably be discounted on the Thorung La, which does not receive much. Wind can shift a surprising amount of snow in exposed places but tends to sweep those places bare whilst depositing snow in sheltered spots and on the lee side of a ridge or pass. Much depends on whether the newly fallen snow is wet or dry. Wet snow is usually more resistant to wind (and melting generally) but more likely to form avalanches quite quickly on the low angled, convex slopes on either side of the TL. Dry snow will blow away quickly in a strong wind but will be slower to avalanche on the TL slopes.

However, from the viewpoint of safety as opposed to comfort, it is not really the removal of snow that is important but its consolidation. It is consolidation that reduces the probability of avalanche, which is the real safety issue on the TL after substantial snowfall. Dry slab avalanches mainly occur at between 30 and 45o and are not likely on the TL path. However they would be possible from the concave flanks of Thorung Peak (south of the La) and Yakwakang (north of the La). Wet snow avalanches occur most readily on convex slopes and can form on gradients as low as 25o. They are much more likely to start on the TL path, particularly just before the top and just after the top.

Taking all that into consideration, I would be happy to cross the TL after 1m of dry snow after about three days of sun and wind. After 1m of wet snow I would wait longer - perhaps five days of sun and wind. If the weather was overcast, then add a few days for both.

Disclaimer: I am assuming quite a lot here. It is always better to follow competent local advice!

The American embassy in Kathmandu has set up an emergency number for people concerned about missing US citizens in the Annapurna region:
US Embassy in Nepal

There are live updates on rescue efforts from the Trekking Agencies' Association of Nepal

When I went up KP in 2007 it had snowed the previous day, and there was about a foot of snow on the track. Walking up at 4am there was a groove in the path from the trekkers ahead of us. After the sunrise we headed down about 8am, and the snow was almost completely melted, being in direct sunlight. I was totally surprised by this. So direct sun can melt snow at a rapid rate.

A question to "old Nepal hands" on this forum: I wonder if this tragedy was avoidable? Those sudden snowstorms were caused by the end phase of a cyclone that had ravaged India some days before. It seems that most cases of severe weather in Nepal trekking areas in high season (October-November) are caused by cyclones. I remember a similar case of Phailin cyclone (luckily without deaths) in mid-October 2013, as I was starting my trek. Such outbreaks are possible to predict at least a few days in advance, as the cyclone moves inland.

Maybe an "early warning system" can be established in Manang and lodges directly before the pass (Thorung Phedi, Thorung High Camp)? For example, in case of bad weather forecast notice would be sent to Manang (by the Himalayan Rescue Association, TAAN or ACAP?) and a big warning sign put on the trail, similarly to avalanche warning in mountains in Europe. A notice could be also sent to Thorung Phedi and Thorung HC to put a similar sign there and declare the trail closed.
Such closure would be needed usually only for 2-3 days, as in most cases fair weather returns quite quickly in October.

The cost of such system would be very low, as HRA, TAAN and ACAP are already present in Manang. What do you think about it? Maybe it would make sense to suggest it to them?

The latest news from the Trekking Agencies' Association of Nepal is that rescue efforts have been halted for the night in Manang and Mustang Districts because of poor visibility. The latest reports cite the death toll at 24, with up to 112 trekkers unaccounted for. TAAN will be publishing a detailed update later today.

If anyone has returned from the affected region in the last few days and can provide on-the-ground information, please get in touch with me directly via the forum.

The Trekking Agencies' Association of Nepal has published a list of trekkers rescued from Annapurna here - or navigate to http://www.taan.org.np/live/.