12 November 2018

A dangerous, valley-blocking landslide in Jomda County, Tibet

Posted by Dave Petley

A dangerous, valley-blocking landslide in Jomda County, Tibet

On Sunday Xinhua reported heightened concern about the Jomda County landslide dam in Tibet:-

More than 25,000 people have been evacuated as the water levels continue to rise in a landslide-formed barrier lake in Tibet Autonomous Region, local authorities said Sunday.  The municipal government of Changdu in Tibet said the water level has risen 57.44 meters with an estimated 469 million cubic meters of water storage as of 9 a.m. on Sunday.  As of Saturday, 42 temporary settlements, equipped with basic living necessities, have been set up for relocated villagers, with medical teams stationed near the settlements.

I reported on this landslide almost a fortnight ago.  It is now clear that a second very major failure has occurred at this site, blocking the valley completely.  This Planet Labs image, collected today (12th November 2018 at 03:40 am UT), shows the scale of the landslide and of the blocked valley:-

Jomda County

The major valley-blocking landslide in Jomda County, Tibet. Planet Labs 3-band PlanetScope scene collected on 12th November 2018, used with permission.

.

This Planet Labs image, collected on 10th November, shows the scale of the lake that has developed:-

Jomda County

The lake formed by the major valley-blocking landslide in Jomda County, Tibet. Planet Labs 3-band PlanetScope scene collected on 10th November 2018, used with permission.

.

Whilst this image shows the scale of the threat to the town of Bolo, upstream from the dame (the location can be seen in the image above):-

Jomda County

Flooding in the vicinity of the town of Bolo induced by the lake formed by the major valley-blocking landslide in Jomda County, Tibet. Planet Labs 3-band PlanetScope scene collected on 10th November 2018, used with permission.

.

This looks to be a dangerous situation that needs very careful management.  Some reports suggest that overtopping is expected today (12th November).

Reference

Planet Team (2018). Planet Application Program Interface: In Space for Life on Earth. San Francisco, CA. Planet.com