Three-quarters of annual rain in the Himalayas arrives in the monsoon season from June to September. Within this rainy period are sudden and extremely intense cloudbursts, which often “pop” over a relatively small area (akin to a cloud bursting open like a balloon).
As climate change is making these cloudbursts and other forms of heavy rainfall more intense and more frequent in the Himalayan foothills, the hilly slopes are becoming saturated more frequently, and thus unstable. Rainfall-triggered landslides are already happening extensively across the Himalayas, and things are likely to get worse.
From July to August 2023, the Indian Himalayas, particularly the state of Himachal Pradesh in the northern part of the country, experienced an unprecedented number of cloudbursts which triggered thousands of devastating landslides. The state’s disaster management authority reported that by the end of August, heavy rain and rainfall-triggered landslides had caused 509 fatalities, destroyed at least 2,200 homes and damaged a further 10,000. It is estimated that Himachal Pradesh’s losses from this period amount to US$1.2 billion. Much of the destruction took place during two short periods, one in mid-July and one in mid-August.
