In many parts of the country, it has been raining for an extended period as if it were the rainy season. There is a possibility that heavy rain will continue over a widespread area for several more days, so people need to beware of landslides and flooding.
Record rainfall amounts have been observed mainly in western Japan since the rain began to fall on Aug. 11, with some areas having accumulated over 1,000 millimeters. At one point, the Japan Meteorological Agency issued special heavy rain warnings to Saga, Nagasaki, Fukuoka and Hiroshima prefectures.
The number of houses flooded in Kyushu and other areas has reached several thousands, and the number of people told to evacuate nationwide is in the millions. Mudslides and flooding of roads continue to occur in various parts of the nation, leaving some people dead or missing. The central and local governments need to do their utmost in search and recovery efforts.
Heavy rain like this usually occurs around July, when there is a stationary seasonal rain front. This year, however, a high-pressure system in the Pacific Ocean that should be over Japan is farther south, creating in the vicinity of Honshu a long front as in the rainy season.
When the temperature rises by 1 C, it is said that the amount of water vapor in the atmosphere increases by 7%. Heavy rain has poured down over a wide range of areas as a result, with this atmospheric pressure pattern similar to that in the rainy season appearing amid the high heat of midsummer. In recent years, linear precipitation bands that have caused damage in various areas have also been verified.
This month, the Intergovernmental Panel on Climate Change (IPCC), an expert body of the United Nations, compiled a report stating that the effects of global warming are clearly starting to appear. It is feared that torrential rains said to occur once every several tens of years will continue to occur almost annually.
This time, in addition to rivers overflowing, there have been cases of inundation of drainage facilities, which occurs when rainwater flowing into sewage pipes exceeds the drainage capacity and spews back out to the ground to cause flooding. As such flooding inside drainage facilities can occur suddenly even in urban areas, caution is needed.
It has been raining on and off. It is difficult to determine when to evacuate, but a temporary lull in the rain does not mean that it is a reassuring situation. There is a possibility that the ground has already come loose. It is necessary to consider evacuating early to avoid doing so at nighttime.
If evacuation centers become crowded, there are concerns about evacuees being infected with the novel coronavirus. Moving to an acquaintance's home or hotel is also an option. Even though people live on the upper floors of a sturdy condominium building, they need to stockpile food and water. Evacuation plans should be made according to the circumstances of each household.
The risk of landslides and floods varies greatly from region to region. In recent years, it has become possible to view various kinds of information, such as distribution of risk of disasters caused by rain that the JMA publishes on its website.
It will be important to be ready to actively gather information on weather and disasters, judge the degree of danger on our own and act accordingly, rather than merely waiting for instructions from the central and local governments.
-- The original Japanese article appeared in The Yomiuri Shimbun on Aug. 17, 2021.
Read more from The Japan News at https://japannews.yomiuri.co.jp/
