Nine people, including several children, have died in a landslide in Tamenglong District in Manipur State, India, on Tuesday 10 July 2018. The incident happened following several days of heavy rain, associated with the Southwest Monsoon, that have caused a series of floods, landslides and other problems across northeast India. Landslides are 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 in Manipur, India, where nine people died on 10 July 2018. News 18 Assam/Twitter.
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
northeast India is largely protected from the Northeast Monsoon by the
mountains to its north and east, though these can also add to the
severity of flooding in the region, with melting snow in the Himalayas
swelling the rivers that flow through these states.
The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.
