Twelve people have died following a landslide in Western Highlands Province, Papua New Guinea, on Saturday 21 March 2020. The incident happened at about 1.00 am local time, in the village of Tendepo Council, close to Tambul, and struck two houses in which families of five and seven were sleeping. The precise cause of the incident is unclear at this time, but March is peak Monsoon Season in Western Highlands Province, with rainfall typically exceeding 270 mm per day, and landslides and flash floods are common in the area. 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 scene of a landslide that killed 12 people in Western Highlands Province, Papua New Guinea, on Saturday 21 March 2020. Loop PNG.
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.
Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.
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