July 28, 2011 12:52
Emergency officials believe the main reason for the heavy damage caused by torrential rain is the weakening effect constant downpours have had on the surface of mountains, triggering devastating landslides. As soon as the record rainy season ended, new torrential downpours followed, prompting weather experts to conclude that this pattern is becoming the norm rather than the exception.
"Unusual weather patterns have now become the norm and we must change the way we deal with disasters," said Jeong Sang-man, head of the National Institute for Disaster Prevention.
The Korea Meteorological Administration gathered data from 60 locations throughout the country that saw more than 30 mm of hourly rainfall from 1971 to 2010 and found that instances of such downpours more than doubled over the last 30 years. From 1971 to 1980, there were only 11.7 times, but that increased to 16.9 in 1981-1990, 18.1 in 1991-2001, and 22 in 2001-2010.
In Seoul, instances of torrential downpours increased from 12 days in 1971-1980 to 37 days in 1991-2000, a three-fold increase over the period. The KMA said the intensity of rainfall in Korea is rising. "It looks like we're seeing more torrential downpours as the amount of water vapor in the atmosphere rises due to climate change," said the KMA. "We need to revamp rules and guidelines for disaster prevention to deal with sudden floods," said Yoon Ju-hwan, a professor at Korea University.
Weather experts at the KMA also believe that a Korean form of squalls, or brief torrential downpours, may have emerged. The heavy rains that fell on Seoul and the central part of Korea between Tuesday and Wednesday resemble a tropical squall that is more common near the equator. Warm air that has been heated by the scorching earth rises to form huge rain clouds that cause these sudden downpours.
But Kim Seung-bae, a spokesman for the KMA, said, "The latest downpours did not result from air heated by the hot earth, but resembled tropical squalls in terms of precipitation patterns where the rain clouds move around, briefly drop sudden huge amounts of rain, and repeat the cycle."
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