Typhoon # 15: Strong winds and high waves in the coastal area, or damage spread on Yokohama Oct. 8 14:03
In the industrial park in Kanazawa-ku, Yokohama, where the typhoon No. 15 was damaged last month, very strong winds were generated locally on the coast during the time the typhoon passed. It turned out that a large amount of seawater was taken to the land side in a short time.
In an industrial estate facing Tokyo Bay in Kanazawa-ku, Yokohama, the revetment was damaged in a wide area due to the high waves caused by Typhoon No. 15, and seawater flowed into factories and offices of about 480 companies, resulting in damage such as machinery breakage. It was.
When Professor Tomoya Shibayama of Waseda University specializes in coastal engineering surveyed the site, the high waves that occurred at that time were about 4 meters, and it was close to the height of the revetment when combined with the storm surge.
And during the time zone when the typhoon around 3:00 am on the 9th, a very strong wind exceeding the maximum instantaneous wind speed of 41 meters occurred locally in the coastal area, and high waves rushed in the form of being hit by this wind and the revetment It was also found that a large amount of seawater seemed to have been brought to the land in a short time.
Prof. Shibayama also created a phenomenon called “a whirlwind” that winds up like a tornado on the point where water reached the hill about 10 meters high near the industrial park, and the seawater sucked up vertically. It is analyzed that there was a possibility that the damage was spread.
As for the high waves, damage is often assumed by the method of determining the height to reach the coast based on the offshore wind, and this case that occurs locally in the coast is not assumed is.
Prof. Shibayama said, “We have never experienced such a strong wind on the coast of Tokyo Bay. We need to devise countermeasures that keep in mind that the strong wind blowing on the coast will increase the damage caused by storm surges and high waves.” It is.