Japan’s Typhoons: Peak Numbers in August, Peak Damage in September

Every summer Japan is struck by typhoons, which at times result in major natural disasters.

The Japanese term taifū (typhoon) is used to describe a low-pressure system that develops over tropical waters in the Pacific Ocean and then heads toward Japan or other parts of East Asia, with maximum sustained surface winds averaging at least 17 meters per second over a period of 10 minutes. Typhoons are carried by higher altitude winds and have the tendency to head north under the influence of the Earth’s rotation. Many of the typhoons that approach the Japanese archipelago are carried by the prevailing westerly winds in a northeastern direction at high speeds.

The number of typhoons per year varies, but the annual average for the period from 1951 to 2017 was approximately 26, of which around 3 hit Japan.

Typhoons’ development is fueled by the energy released when water vapor rising from the warm ocean surface condenses into water droplets within clouds. This is why most of the typhoons that are generated and make landfall occur from July to October, when ocean temperatures are higher.

A list compiled by the Japan Meteorological Agency of typhoons that have caused major damage in Japan reveals that most struck in September. Not only do more typhoons form and make landfall during that month, but it is also the time when the autumn rain front hovers near Japan. At times humid air spinning on the eastern side of the typhoon is swept into the rain front, causing it to become more active and generating torrential rains.

List of Typhoons Causing Major Damage in Japan

Date typhoon hit Japan	Typhoon name	Number of dead or missing	Number of houses destroyed
September 21, 1934	Typhoon Muroto	3,036	92,740
September 17, 1945	Typhoon Makurazaki	3,756	89,839
September 15, 1947	Typhoon Kathleen	1,930	9,298
September 26, 1954	Typhoon Tōyamaru	1,761	207,542
September 26, 1958	Typhoon Kanogawa (Ida)	1,269	16,743
September 26, 1959	Typhoon Isewan	5,098	833,965
September 19, 1990	Typhoon Flo	40	16,541
September 27, 1991	Typhoon Mireille	62	170,447
September 3, 1993	Typhoon Yancy	48	1,784
September 7, 2004	Typhoon Songda	46	64,999
October 20, 2004	Typhoon Tokage	98	21,350
September 3, 2011	Typhoon (Tropical Storm) Talas	98	4,008
October 16, 2013	Typhoon Wipha	43	1,094

The table above was created by Nippon.com based on data on the Japan Meteorological Agency’s website. Shaded areas are typhoons that struck Japan in September. The data was published by the JMA to show how figures for dead and missing were more than 1,000 persons for major typhoons that struck during the Shōwa era (1926–1989), whereas fatalities were less than 100 persons during the Heisei era (1989–present).

(Translated from Japanese. Banner photo: © Pixta.)