Fact Check: A look at how the Idukki landslide occurred

The landslide happened at 10:45 pm on August 6 at Pettimudi, a hamlet in Rajamala ward under Munnar village panchayat in Kerala’s Idukki district. Workers of Kanan Devan Hills Plantations Company (P) Ltd were living in Pettimudi. Rajamala includes Eravikulam National Park, and the landslide was triggered from a shola forest region in the national park. Rocks, slurry and sludge crashed down a distance of around 1½ km to a patch of valley in Pettimudi, crushing the single-room houses of estate workers that stood in two rows, face to face.

Vulnerable area

The location where the landslide was triggered, according to the Kerala Geology Department, has a 40° slope, and any slope above 20° is vulnerable to slipping during heavy rain. The soil has a high content of sand, which absorbs more water, takes a loose form, and is at risk of slipping down.

A look at the hamlet before and after the Idukki landslide

An analysis of landslides in Idukki by the State Disaster Management Authority has shown that high-intensity rainfall saturates the soil on the slopes. Soil with higher clay content has high water retention capacity and low drainage capacity, leading to high water pressure in the slope material.

Human interventions such as heavy loading on the slopes caused by buildings on cut-and-fill ground, without adequate protective measures on the uphill and downhill sides, have made the area particularly vulnerable. Frequent slides have resulted in blockage of river channels and changed the river’s course.

Officials said 83 people were living in 30 single-room, sheet-roofed quarters, provided by the estate.

An analysis of landslides in Idukki by the State Disaster Management Authority has shown that high-intensity rainfall saturates the soil on the slopes.

The victims

Officials said 83 people were living in 30 single-room, sheet-roofed quarters, provided by the estate. 12 of them were rescued by residents of another settlement. So far, 49 bodies have been recovered in laborious rescue operations. Local people said more are missing as many had come as guests from other areas. Only a handful of residents, who were away, have survived. The victims included 31 persons of one extended family who lived in adjacent quarters, and six temporary staff at the Eravikulam National Park. Nineteen schoolchildren have either died or are still missing.

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Previous landslides

2019: 59 persons died in Kavalappara, Malappuram. In Puthumala, Wayanad, another landslide killed 17.

2018: Invarious landslides in Idukki, 60 died. Elsewhere, a landslide in Thamarassery, Kozhikode killed 14, and another in Kurancheri, Thrissur killed 1.

The location where the landslide was triggered has a 40° slope, and any slope above 20° is vulnerable to slipping during heavy rain.

Also read | Kerala: Idukki landslide toll rises to 49, search ops to continue