Friday 25 September 2020

Landslides kill at least eleven in Nepal.

Eleven people are known to have died and five more are missing after three communities in Nepal were hit by landslides on Thursday 24 September 2020. The first incident hit the village of Tamadi in Syanja District at about 5.30 am local time. Destroying a house occupied by a family of ten. Nine of those inside the house were killed, while one, sixteen-year-old Manisha Nepali, suffered severe injuries to her legs, and is currently being treated in the Gandaki Medical College in Pokhara. Those killed in the incident have been identified as two men, three women, a teenage girl, two boys, and a seven-month-old baby.

Rescuers at the site of a landslide which destroyed a house with ten people inside it in Syangia District, Nepal, on 24 September 2020. Hobindra Bogati/The Kathmandhu Post.

A second landslide in Syangia is reported to have killed an as yet unidentified 16-year old, while at Phoksingkot in Palpa District another family home was destroyed, leaving a pregnant 27-year-old woman dead and four other people missing. All three incidents are reported to have happened following heavy rains associated with Nepal's annual Monsoon. Monsoon Season, and is reported to have destroyed seven houses and a school. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.

The aftermath of a landslide in Palpa District on 24 September 2020, which left one person dead and four more missing. Kathmandhu Post.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate. This situation is particularly intense in South Asia, due to the presence of the Himalayas. High mountain ranges tend to force winds hitting them upwards, which amplifies the South Asian Summer Monsoon, with higher winds leading to more upward air movement, thus drawing in further air from the sea.

Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

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