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Prefectural Road Okutama-Akiruno Line Left bank of Hirai River (Hinode Town)● Typhoon: A typhoon is a tropical low-pressure system of which the maximum wind speed isabout 17 m/s or more among the tropical low-pressure systems developing in the north- western Pacific Ocean or the South China Sea.Akigawa Yamada area (Akiruno-shi)(2) Damage Caused by Wind and Rain　Current Situation　We have experienced every year natural disasters along with unprecedented heavy rain and typhoons all over the country possibly due to global climate change. 　The Tokyo Metropolitan Government has steadily reduced flood damage by taking comprehensive measures through construction of river walls resistant to the rainfall of 50 mm per hour and upgrades to sewers as well as by city development. However, the number of times we experience rainfall over 50 mm per hour has been increasing in recent years. These torrential rains and typhoons have caused flood disasters.Damage by Torrential Rain　In September 2005, Typhoon No. 14 and the autumn rain front caused torrential rain with precipitation of 100 mm/hr. in the western wards area. The Kanda River, the Myoshoji River, and the Zenpukuji River flooded, causing damage to about 6000 buildings in Suginami-ku, Nakano-ku, etc.; the Disaster Relief Act was applied.Damage Caused by Typhoons　In October 2013, as Typhoon No. 26 approached, Moto-machi in the Oshima-machi district experienced torrential rain of 122.5 mm per hour and 24-hour rainfall of 824.0 mm, both of which are the highest figures ever recorded in the history of observation.　This rainfall caused large-scale landslides in the Moto-machi, Senzu, Okada, and other areas, causing a large number of casualties. Extensive damage was also caused to buildings, roads, lifelines, and other structures. Casualties in the Tokyo area caused by this typhoon were 40 persons dead or missing and 25 persons injured.　In October 2019, as Typhoon No. 19 approached, the west area of Tama experienced a record rainfall of 650 mm from 11 to 13 of October, and a special heavy rain warning was irrued in 25 municipalities including the Tama area. In the Tokyo metropolitan area, 7 rivers such as Aki River flooded, while river walls of 4 rivers including Asa River collapsed at 10 different sites. About 850 houses were flooded above or below floor level in the Tokyo metropolitan area due to this Typhoon.Disaster-Prone Locations　Caution is required in the following areas of Tokyo.● For storm surges: Lands near a shoaling beach, at the end of a bay, or ● Storm surge: An offshore rise of water due to a typhoon or a strong wind. When the water level rises above the floodwalls, coastal areas and downriver lowlands may be flooded.● Torrential rain: Concentrated heavy rain for several hours in the same location, resulting in a rainfall of 100 mm to several hundred millimeters. Heavy rain and thunderstorms that last for hours at a time are a characteristic.at the mouth of a river, coastal lands near sea level● For floods: Alluvial (low-lying) plains and riverbanks● For landslides: Reconstructed lands, alluvial fans, mountainous regions10