Abstract
During June 28th-July5th, 1938, Central Japan experienced a severe rainfall which is the heaviest ever recorded during any month since the Meteorological Observatories at Mito, Tokyo, Yokohama, Numazu and Kobe were opened. For several days prior to June 30th there had existed a stationary front running from northeast to southwest across Southern Kwanto district between cool air to the north and warm and moist air to the south. These conditions are shown on the chart for 0600 J. M. T. June 29th. During 28th-30th a typhoon continued to move ENE on this front. The full violence of the exceptionally heavy rains occurred during 29th. Rain commenced to fall few days before and was almost continuous until morning on the 30th During the whole period on the 29th 276.6mm of rains were recorded at Mito, 278.3mm at Tokyo, 268.3mm at Yokohama and 363.5mm at Numadu. The normal monthly total of rainfall in July in Tokyo is 132.3mm and the maximum fall for any one day hitherto recorded is 193.7mm. The 1200 J. M. T. Chart for June 30th showed that the centre continued to move ENE or NE passing just south of Tokyo.
After 1800 J. M. T., as the typhoon moved farther away, the wind velocity fell and it was fine weather. One day later there formed a new front of stationary type running along Japan proper between cool air to the north and warm and moist air to the south. During the second period of the exceptionally heavy rainfall July 5th 270.4mm of rain were recorded at the Kobe Meteorological Observatory.
As might be anticipated serious damage was done in Japan proper, mostly due to floods, 715 lives were lost and the total momentary loss from this storm has been variously estimated at ¥1, 000, 000, 000 to ¥2, 000, 000, 000. Full report on the heavy rainfall may be seen in the “Gou Hokoku” (253 pages with 32 plates), published by the Central Meteorological Observatory.
