Review article: Snow and ice avalanches in high mountain Asia – scientific, local and indigenous knowledge
Abstract. The cryosphere in high mountain Asia (HMA) not only sustains livelihoods of people residing downstream through its capacity to store water but also holds potential for hazards. One of these hazards, avalanches, so far remains poorly studied as the complex relationship between climate and potential triggers is poorly understood due to lack of long-term observations, inaccessibility, severe weather conditions, and financial and logistic constraints. In this study, available literature was reviewed covering the period from the late 20th century to June 2022 to identify research and societal gaps and propose future directions of research and mitigation strategies. Beyond scientific literature, technical reports, newspapers, social media and other local sources were consulted to compile a comprehensive, open access and version controlled database of avalanche events and their associated impacts. Over 681 avalanches with more than 3131 human fatalities were identified in eight countries of the region. Afghanistan has the highest recorded avalanche fatalities (1057) followed by India (952) and Nepal (508). Additionally, 564 people lost their lives while climbing peaks above 4500 m a.s.l., one third of which were staff employed as guides or porters. This makes it a less deadly hazard than in the less populated European Alps for example, but with a considerably larger number of people affected who did not voluntarily expose themselves to avalanche risk. Although fatalities are significant, and local long-term impacts of avalanches may be considerable, so far, limited holistic adaptation or mitigation measures exist in the region. These measures generally rely on local and indigenous knowledge adapted with modern technologies. Considering the high impact avalanches have in the region we suggest to further develop adaptation measures including hazard zonation maps based on datasets of historic events and modelling efforts. This should however happen acknowledging the already existing knowledge in the region and in close coordination with communities and local government and civil society stakeholders. More research studies should also be attempted to understand trends and drivers of avalanches in the region.
Anushilan Acharya et al.
Status: final response (author comments only)
RC1: 'Comment on nhess-2022-287', Markus Eckerstorfer, 22 Feb 2023
- AC1: 'Reply on RC1', Anushilan Acharya, 23 Apr 2023
RC2: 'Comment on nhess-2022-287', Yves Bühler, 09 Mar 2023
- AC2: 'Reply on RC2', Anushilan Acharya, 23 Apr 2023
Anushilan Acharya et al.
Anushilan Acharya et al.
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I am very impressed by the amount of data you have gathered on avalanche events in HMA. Your GIS based database is great and a good starting point for further studies and initiatives as you write in your manuscript. This work is of high value and very timely for the people living in these areas and their livelihood being threatened by snow and ice avalanches (and other slope and glacier hazards).
I suggest minor revision that mostly concerns some clarifications, writing (I am not an English native speaker myself) and the use of technical terms.
Doesn’t – “does not” in several places
40: consider splitting up this very long sentence
43: since you mention avalanches for the first time here, maybe write “snow avalanches (hereafter also called avalanches)”
46: I would delete Eckerstorfer and Malnes, 2015 here, since it is not the correct paper to cite on how avalanches affect socio-economic activities. McClung’s Handbook is fine here.
55: not sure how important these past death tolls are here. Consider looking up major avalanche accidents in Asia, for example in Panjshir, Afghanistan in 2015.
78: I do not think that avalanche related climate change studies are that limited anymore. There are numerous studies from Switzerland and France that should certainly be mentioned here.
108: until here I thought your review would only concern ice avalanches. I believe you should consider giving an overview over ice avalanches in the introduction, similar to the comprehensive introduction to snow avalanches.
147: depth-hoar avalanches is not a commonly used term. Could you write “avalanches that release on the ground” or “full depth avalanches”.
Section 3.1 you are switching a bit between past and present tense. Consider writing it all in past tense.
151: it is not correct that a deep snowpack favors depth hoar growth. In fact, it is the opposite. A thin snowpack allows for a large temperature gradient between ground and atmosphere and thus kinetic growth of snow crystals into depth hoar.
156: it does not make sense that SDAs (surface layer dry slabs) occurred with a persistent weak layer. However, it makes sense that they were triggered by heavy snowfall and wind. Consider deleting the information on persistent weak layers. These would be present with FDA for example.
159: if a storm triggered 37 avalanches, it does not make sense that half of them were triggered by precipitation. What about the other half?
162: sentence is not understandable. Please rewrite.
167: please check again if these avalanches predominantly released between 25 and 35 degrees. Where these wet snow avalanches or slush flows?
172: consider splitting up this very long sentence
176: not really sure what a moist slab avalanche is. In my opinion the classification is either wet or dry.
178: we usually talk about wind-loaded slopes. Thaw avalanches is not a term commonly used. I guess you mean wet snow avalanches?
189: what do you mean by weakened layers?
195: consider splitting up this very long sentence
200: contradicting who? Your opinion?
Figure 1a: this seems to be a glide crack that precauses a glide avalanche.
Figure 1d: I wonder if the avalanche eroded the gully. Would you rather not think the gully was already there, caused by some other process?
Figure 3a: the color indicating glaciated areas is not the same as in the legend.
Figure 3b: how do I interpret the map? If a circle over an area shows 30-40 fatalities, are all of these fatalities from a single event, or the sum of fatalities from multiple events over multiple years?
Figures 3 and 4: what do you mean by “some recorded impact”?
Figure 4b: what are impacts by month?
Figure 4a: the figure is not easy to read and interpret. I am not sure there is much information to be gained from Figure 4b. maybe consider showing the stacked fatalities per year in Figure 4b instead.
Table 2: if you do not know the type of slope hazard (NA), why are these events included then in the table? Does it make sense to mention “slab avalanche” in the table? I guess its falls into the snow avalanche category anyway.
330: you initially stated that you are not considering high altitude mountaineering avalanche fatalities. However, here you have a whole section on it. I find it interesting and I think you should slightly rewrite your scope of the study in the introduction.
Section 6: interesting topic, however, very thinly described. Could you add some references here for further reading?
453: love the story about people basically growing rock glaciers. Have heard that in some lectures before!