Typhoon Fanapi Crosses Southern Taiwan; Flooding is Main Concern

Catastrophe risk modeling firm AIR Worldwide reports that Typhoon Fanapi made landfall on the east coast of Taiwan on Sunday morning, September 19 (0:00 UTC). The storm, which had been a Category 3 typhoon for several days, weakened slightly just before landfall due in part to having undergone an eye wall replacement cycle and to the effects of increased wind shear caused by an anticyclone to the north of the storm.

Fanapi arrived onshore near rural Fengbin township (estimated population 5,000) in Taiwan’s Hualien County as a strong Category 2 on the Saffir Simpson Wind Scale. Winds at landfall were 80 knots 10-minute average, or about 105 mph 1- minute sustained wind speeds.

Earlier in the week, Fanapi was forecast to track very close to Taipei. According to AIR, the storm took a more southerly course and made landfall about 40 kilometers south of Hualien City (est. pop. 115,000), the capital of the county of the same name and Taiwan’s largest port. The stretch of coast along which Fanapi made landfall is relatively sparsely populated, with coastal mountains separating the shore from an agricultural region further inland.

At Fanapi’s wind speeds, roofs, awnings and signage can be torn off. According to AIR, low- to mid-rise buildings in Taiwan are typically of reinforced concrete or reinforced concrete frames with brick infill walls. The first story in these structures is used for commercial purposes with residential occupancy above. The mixed occupancy use in Taiwan makes the vulnerability of residential and commercial lines of business very similar. It should be noted that in Taiwan’s rural and mountainous regions, construction is of poorer quality and thus less wind resistant.

Gusty winds reached as far north as Taipei, where several cars were reported to have been crushed by downed trees. The primary concern, however, is flooding. According to AIR, by the time Fanapi made landfall, Yilan County to the north had already recorded more than 300 mm (12 in.) of precipitation. Twelve hours later, as the storm was exiting Taiwan and heading into the South China Sea, areas in southern Taiwan had received more than 800 mm (30 in.) of rainfall and these totals may ultimately rise to 1,000 mm (40 in.).

After making landfall, Fanapi turned south, away from Taipei. The storm tracked across the island for the next twelve hours and exited near the western city of Tainan, Taiwan’s fourth largest city. Sustained winds had diminished to about 70 knots (10-minute average) or about 92 mph (1-minute). However, heavy rainfall, which is likely to continue over southern Taiwan for up to another 12 hours, remains the chief concern.

According to AIR, Fanapi is the first to strike Taiwan this season. Its effects, however, will undoubtedly be compared to last year’s Typhoon Morakot, which killed more than 700 people, most from flooding and landslides. Morakot, which tracked further north than Fanapi, closer to Taipei, is estimated by AIR to have caused total economic losses of TWD 110 billion ($3.3 billion).

AIR is continuing to monitor precipitation accumulations in Taiwan from Typhoon Fanapi even as the storm heads towards China’s south coast, where a landfall between Guangdong and Fujian provinces is expected tomorrow. Updates will be issued as warranted by events.

Source: AIR Worldwide