Eight people have been confirmed dead following a landslide in Nan Province in northern Thailand. The event happened at about 6.10 am local time on Saturday 28 July 2018, when a 200 m wide section of the hillslope above the village of Baan Huay Khab collapsed, destroying most of the community's houses, following heavy rains in the region associated with the Southwest Monsoon. 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 number of fatalities was initially feared to be much higher, but all local residents have now been accounted for,
The aftermath of a landslide that destroyed the village of Baan Huay Khab on 28 July 2018. Thai Residents.
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.
Much of Southeast Asia has two distinct Monsoon Seasons, with a Northeast Monsoon driven
by winds from the South China Sea that lasts from November to February
and a Southwest Monsoon driven by winds from the southern Indian Ocean from March to October. Such a double Monsoon Season is common
close
to the equator, where the Sun is highest overhead around the equinoxes
and lowest on the horizons around the solstices, making the solstices
the coolest part of the year and the equinoxes the hottest. However
northern Thailand is largely protected from the Northeast Monsoon by the
mountains
separating the country from Myanmar.
The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.
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