Like much of the world, I watched and rewatched the videos of the catastrophic flood that have been filtering out of Nepal since Wednesday with horror and sadness.
But unlike many, I have an intimate knowledge of this part of the world, where I first traveled as an undergraduate geology student in 2005 to study how glaciers in the Khumbu region disintegrate into hazardous lakes. I’ve made six expeditions there over the last two decades.
Because of the remote location, scientists don’t know what precisely triggered Wednesday’s disaster — yet. What’s clear at this point is that a giant hunk of glacier peeled off the side of the mountain, tumbled down 4,000 vertical feet and slammed into a tributary of the Bhote Koshi River in China.
Originally misidentified as an earthquake, the mountain-shaking event registered as a 5.2 magnitude seismic event. Moments later, a wall of rocks and water blasted through the Gyriong Port building as the flood barreled down the valley.
The source of the water remains a mystery.
In many catastrophic floods in the Himalaya, glacier lakes are to blame. When Nepal’s glaciers were healthy, they bulldozed down mountains and pushed up piles of rocky debris hundreds of feet high to form features glaciologists call moraines.
