Six people have died in two separate landslides in the Philippines on Saturday 13 January 2017. Four people died in the city of Tacloban on Leyte Island, when a landslide pushed over a perimeter wall onto a house at abut 9.00 pm local time. The four have been identified as village secretary Inday Hernandez, her husband, one of her children, and Delia Carzon, a 67-year old woman employed by the family as a watchman. It a separate incident two people described as pensioners were killed by a second landslide in Pantar town in Lanao del Norte Province on Mindanao Island.
Rescue teams at the site of the 13 Jabuary 2017 Tacloban landslide. Cristina Gonzalez Romuldez.
The incidents occurred following heavy rains across the Philippines associated with the Northern 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.
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.
Southeast Asia has two distinct Monsoon Seasons, with a Northeast Monsoon driven by winds from the South China Sea during the Southern Hemisphere Summer and a Southwest Monsoon driven by winds from the southern Indian Ocean in the Northern Hemisphere Summer. 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.
The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.
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