What to Know About the Deadly Landslides in Southern India

Earlier this week, multiple landslides hit the Wayanad district of India’s Kerala State, killing more than 126 people and injuring hundreds of others. The landslides were caused by torrential rains that lasted for days, uprooting trees, burying villages, and cutting off roads and communication lines. State officials described it as one of the worst natural disasters Kerala has ever witnessed.

Rescue workers continue to recover and identify bodies, and with more than 180 people still missing, the death toll is likely to rise. The state government has set up temporary hospitals and shelters, and sent rations and clean water to thousands of affected residents. It declared a two-day mourning period on Tuesday.

Wayanad is a hilly region in the northeastern part of Kerala known for its natural beauty and wildlife. A big tourist attraction, its slopes carry spice plantations and its valleys contain paddy fields.

But the elevation, the angle of the slopes, a thick bed of loose soil that sits atop hard rock and rivulets created by heavy rainfall create the perfect conditions for landslides, said S. Sreekumar, a geologist who has worked with multiple government bodies on disaster management. New construction and irrigation methods used by farmers have also compromised the natural drainage system, he said.

“There are high slopes and people are settled at the base of the slope,” Mr. Sreekumar said. Extreme and frequent rainfall owing to climate change are also “a big contributor, no doubt about that.”

Kerala is one of India’s most developed and populous states, with high per capita income and education levels. It is prone to natural calamities because of its topography and a heavy monsoon season. A construction boom fueled by the