Initially, Rashid told this writer, he was not very successful because much of the area was heavily cloud covered, while the timing of satellite overpasses was another constraint.
“Fortunately, Landsat 9 had an overpass shortly after the event, and the imagery provided a much clearer view of the failure zone, on 26th August.
This was particularly useful because it allowed to examine the area where the event appears to have originated in considerably greater detail,” Rashid said.
Planet imagery and observations shared by geomorphologist Dan Shugar of the University of Calgary in Canada had already helped him identify the source area a day earlier.
The source area lies at around 5,200 metres above sea level, on a very steep slope.
When images of the catastrophic floods in Nepal began circulating on social media, the scale and apparent violence of the event immediately caught Kashmiri geoscientist Irfan Rashid’s attention, and he scrambled to look for the landscape behind the headlines.
Rashid, Head of the Department of Geoinformatics at Kashmir University who spends much time in his lab and high-altitude landscapes studying glaciers and glacial hazards in Kashmir and Ladakh, began searching satellite archives for a glimpse of the source area “when I first became aware of the event through social media, particularly posts circulating on Instagram and X.”
Rashid examined imagery from United States Geological Survey (USGS) Earth Explorer, Planet and the European Space Agency’s Sentinel missions.
It was not straightforward. Initially, Rashid told this writer, he was not very successful because much of the area was heavily cloud covered, while the timing of satellite overpasses was another constraint.
“Fortunately, Landsat 9 had an overpass shortly after the event, and the imagery provided a much clearer view of the failure zone, on 26th August. This was particularly useful because it allowed to examine the area where the event appears to have originated in considerably greater detail,” Rashid said.
Planet imagery and observations shared by geomorphologist Dan Shugar of the University of Calgary in Canada had already helped him identify the source area a day earlier. Taken together, the imagery pointed towards what Rashid described as a major ice collapse from the frontal part of a glacier, followed by the rapid downstream mobilisation of ice, rock, debris and water.
What particularly caught Rashid’s attention was the apparent magnitude of the collapse. The source area lies at around 5,200 metres above sea level, on a very steep slope. Preliminary estimates suggest that the event may have involved 100-200 million cubic metres of ice, rock and debris, although Rashid stressed that this remains an early estimate requiring much more rigorous analysis.
