Typhoon Flo (1990)

Pacific typhoon in 1990

Typhoon Flo (Norming)
Flo after peak intensity on September 17
Meteorological history
FormedSeptember 8, 1990
ExtratropicalSeptember 20, 1990
DissipatedSeptember 22, 1990
Violent typhoon
10-minute sustained (JMA)
Highest winds220 km/h (140 mph)
Lowest pressure890 hPa (mbar); 26.28 inHg
Category 5-equivalent super typhoon
1-minute sustained (SSHWS/JTWC)
Highest winds270 km/h (165 mph)
Overall effects
Fatalities40 total
Damage$918 million
Areas affectedJapan

Part of the 1990 Pacific typhoon season

Typhoon Flo, known in the Philippines as Typhoon Norming, was a long-lived typhoon that brought destruction to much of Japan during September 1990. Flo originated from an area of convection that first formed to the southeast of the Marshall Islands on September 7. Five days later, the disturbance obtained tropical depression status, and on September 13, intensified into a tropical storm. Tracking west-northwest as it rounded a subtropical ridge, Flo slowly deepened, and on September 15, became a typhoon. After developing an eye, Flo began to rapidly intensify, and on September 17, Flo attained peak intensity. Shortly thereafter, the typhoon began to recurve to the northeast towards Honshu in response to deepening troughs to the northwest and north of the system, which resulted in a weakening trend due to increased vertical wind shear despite remaining over warm water. On September 19, Flo made landfall on southern Honshu, becoming the first typhoon to hit the Kii Peninsula in 11 years, and thereafter started to transition into an extratropical cyclone. The extratropical remnants of Flo were last noted on the morning of September 22.

Typhoon Flo was the strongest system to affect Japan since 1959. For a period of three days, the typhoon dropped heavy rainfall across much of the Japanese archipelago, which inflicted damage in 44 of 47 prefectures. The typhoon also passed just east of Okinawa, coming close enough to drop heavy rainfall. There, four people were killed, four were hurt, and five vessels sunk. On the northeastern side of Shikoku Island, in Kagawa Prefecture, two people were killed, 1,748 homes were damaged, and another 116 homes were destroyed. Across the Amami Islands, 13 people were killed, 29 others were hurt, 917 homes were damaged, and an additional 446 houses were destroyed, resulting in 2,327 homeless individuals. In Okayama Prefecture on the main Japanese island of Honshu, ten people perished and nine others were injured. There, 2,810 homes were demolished, 4,675 others were damaged, and Flo was the worst typhoon to strike the prefecture since 1964. While damage in Tokyo was slight, 260,000 passengers were stranded after 117 trains along the Tōkaidō Shinkansen line were disrupted. Due to a prolonged period of heavy rain, partially caused by Flo, rainfall was 300% of normal in some locations on the island as of mid-September 1990 while sunshine time was a mere 64% of average in Hokkaido Prefecture. Overall, 40 fatalities were reported and 131 others sustained injuries. A total 16,541 houses were destroyed while 18,183 others were flooded. Additionally, 413 ships sunk and 10,365 acres (4,195 ha) of farmland were damaged. The typhoon flooded or cut roads at 418 locations and railroads at 31 spots while there were also greater than 450 landslides. A total of 337 flights were canceled by Japan's four major airlines (Japan Airlines, All Nippon Airways, Japan Air System, and Air Nippon) affecting around 33,000 passengers. Moreover, 245 trains were halted, leaving almost 300,000 stranded. Monetary damage amounted to ¥132 billion or US$918 million across the country.[nb 1]

Meteorological history

Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
  Tropical depression (≤38 mph, ≤62 km/h)
  Tropical storm (39–73 mph, 63–118 km/h)
  Category 1 (74–95 mph, 119–153 km/h)
  Category 2 (96–110 mph, 154–177 km/h)
  Category 3 (111–129 mph, 178–208 km/h)
  Category 4 (130–156 mph, 209–251 km/h)
  Category 5 (≥157 mph, ≥252 km/h)
  Unknown
Storm type
circle Tropical cyclone
square Subtropical cyclone
triangle Extratropical cyclone, remnant low, tropical disturbance, or monsoon depression