4 ms·
Not readily. The events, even with increased frequency, are relatively rare (perhaps a few times a decade), quite sudden, utterly overwhelming, and destructive
by dredmorbius 20d ago
Not readily.
The events, even with increased frequency, are relatively rare (perhaps a few times a decade), quite sudden, utterly overwhelming, and destructive to virtually everything in their path.
The only assured safety practice would be to keep out of the danger zone entirely, and even this is challenging:
- There's very little habitable or arable land, and much of that is in river valleys (e.g., in the heart of the risk zone).
- Many mountainous regions are poor, and Nepal particularly so. Governmental and institutional resources are highly constrained, corruption, opportunism, and risk-taking behaviours are common.
- It's not possible to construct around the risks, as even the most robust structures are utterly demolished. Post-incident imagery shows bare land scrubbed clean near Gyirong Port, for example. Underground shelter might be possible. But ...
- Response times are on the order of seconds to minutes. The elapsed time from the glacial collapse (captured by seismometers) to the debris wall striking Gyirong Port was roughly seven minutes. That's about as much time as would be necessary to climb to a safe(r) elevation or enter an underground shelter. Even then, survivors would have to wait to be dug out, potentially days or weeks later.
- Flood run-ups of as high as 800m (2,6000 ft) were reported within 7-8 km of the start of the incident. Even further down the river valley flood depths hit 9m (27 ft) within 30 minutes. Depending on local topography it would be necessary to move a considerable horizontal distance to reach a safe vertical elevation. Though there's an inverse relation between narrowness of a channel and the direct kinetic risk, in the case of this event, even a fairly broad floodplain would have presented considerable risk, and refuge structures would have to be exceptionally robust to survive and provide protection.
Monitoring of potential risks, advanced warning (that is, of a potential situation rather than a current one), and evacuation of the affected area would be necessary.
Anything constructed within the risk area would have to be seen as a sacrifice zone. Ironically the Gyirong Port was substantially rebuilt this past January following similar, though lesser floods about a year ago which wiped out the Friendship Bridge between China and Nepal. Infrastructure such as roads and bridges might be elevated above river level, but would otherwise have to be rebuilt following events.
Advance warnings are disruptive and often turn out not to reflect a manifest threat. With time, public and business response tends to be to deprecate and ignore such warnings. The region has a literacy rate below 70%, as well as being both an international trade route and tourist region, further complicating communications, awareness, and compliance with emergency preparation and response efforts.
This isn't to say that nothing can be done, but there are no easy choices, and local poverty will make even modest efforts challenging.