Slow-Moving Typhoon: Vigilance Required against Damage Occurring over Wide Area

Editorial

15:00 JST, September 3, 2024

Typhoon Shanshan, which hit the Japanese archipelago, followed an unpredictable path at a slow speed, causing damage over a wide range of areas. This was a rare phenomenon that differed from previous typhoons. Similar storms are expected to occur more frequently in the future due to drastic climate change, and vigilance is essential.

The 10th typhoon of the year landed in Kagoshima Prefecture on Thursday, passed through Kyushu and Shikoku and turned into a tropical cyclone off the Pacific Ocean on Sunday. During this period, it moved about as fast as a bicycle and stayed in the same areas, causing storms for an extended period of time.

The areas the typhoon passed through suffered such damage as flooded houses and collapsed bridges. Miyazaki Prefecture saw gusts of wind that were believed to be a tornado. The number of deaths and injuries exceeded 100 people nationwide.

The typhoon was initially expected to land in an area stretching from the Kanto to Kinki regions. However, because of a prevailing Pacific Ocean high-pressure system, it took a more westerly course than expected. As the westerlies were also blowing more northerly than usual, the typhoon could not ride on the winds and its speed did not increase.

It was difficult to predict the typhoon’s course, so local governments must have struggled to determine the right timing to alert their residents.

Typhoons are becoming larger due to the impact of global warming. There will likely be more cases in which typhoons take unpredictable courses that have them moving at slower speeds and heading in unforeseen directions. Local governments should draw on this experience when devising their future measures.

Another feature that should be especially noted about the recent typhoon is the “predecessor rain event.” As the typhoon moved northward, warm and moist air flowed in, stimulating the autumn rain front.

This caused heavy rainfall in the Kanto and Tohoku regions, far away from the typhoon, due partly to the development of linear precipitation zones.

Landslides, overflowing rivers and flooded roads occurred in both mountainous areas and urban districts. In some cases, the drainage capacity could not keep up with the large amount of rainfall in the short period of time. It is necessary to verify whether current facilities can cope with record-breaking rainfall like that from the latest typhoon.

A number of Shinkansen services were suspended, and flights were canceled. There must have been many people who did not know what to do when they were stranded at their travel destinations at the end of their summer vacation. In such cases, transportation companies should promptly provide information on places where people can wait, as well as alternative means of transportation.

There were also large-scale power outages in areas of Kyushu. If air conditioners are disabled during a heat wave, lives could be lost due to heatstroke.

It is important for each member of society to take what measures they can, such as filling plastic bottles with water and freezing them during normal times, so they can be used as ice packs during a power outage.

When Typhoon Faxai, the 15th such storm of 2019, hit the Boso Peninsula, water outages occurred for an extensive period of time in addition to power outages. It is also important to check if there are sufficient stockpiles of water and food.

(From The Yomiuri Shimbun, Sept. 3, 2024)