Verisk charts impact of Nanmadol, Fiona and M6.9


Verisk charts impact of Nanmadol, Fiona and M6.9

Typhoon Nanmadol (NASA)

According to extreme event modelers at Verisk, Typhoon Nanmadol, the fourth strongest typhoon to make landfall in Japan in the last half century, made its first landfall on 18 September, around 7pm local time, near Kagoshima City on the southwestern tip of Kyushu Island.

The storm then tracked just west of due north over Kyushu Island before turning northeast and tracking along the northern coast of Honshu. Nanmadol is currently located along the north coast of Shimane prefecture and has weakened to a tropical storm.

Around the city of Kagoshima, on the southern tip of Japan’s southerly Kyushu Island, wind and flood damage have been reported. There are widespread reports of downed trees, certain roofs ripped off buildings, and toppled billboards. In addition to impacts from winds, heavy precipitation will also drive losses from Nanmadol. Widespread reports of rainfall of 400mm (about 16 inches) have been reported across Kyushu Island, with a high of 900mm (about 35 inches) reported in Misato town in Miyazaki prefecture.

“There is considerable uncertainty in the reported minimum central pressure at landfall for Typhoon Nanmadol,” Verisk said.

The Japan Meteorological Agency reported a central pressure at landfall of 935 mb, while the Joint Typhoon Warning Center reported a pressure of 947 mb just prior to landfall, and 958 mb just after.

Hurricane Fiona has made two landfalls in the Caribbean thus far–the first on 18 September, in the afternoon, on the southwestern corner of Puerto Rico near Punta Tocon, followed by a second landfall near Boca de Yuma, Dominican Republic early on 19 September, with maximum 1-minute sustained winds of 90 mph, per the National Hurricane Center.

“After initially battling wind shear, Fiona began to organise and strengthen over the weekend, reaching hurricane status on Sunday morning,” Verisk said, adding that catastrophic flooding is likely to be the main impact from Fiona.

Up to 20 inches of rain, with the potential for locally up to 30 inches are forecast for Puerto Rico, with up to 12 inches forecast for parts of eastern Dominican Republic. Power is expected to be out across Puerto Rico for several days, Verisk said, citing LUMA energy, which is the primary power utility there. The outage will not be as severe however as that caused by 2017 Hurricane Maria, which left much of the island without power for the better part of a year.

Several rivers in eastern Puerto Rico are at or near flood stage, and mudslides and landslides are likely in parts of both territories impacted by Fiona as the precipitation continued on 19 September, Verisk said.

Fiona is expected to continue its northward turn and to strengthen. The eastern Bahamas and Turks and Caicos will experience tropical storm force winds and heavy rainfall as the storm passes, with hurricane force winds possible over Turks and Caicos. From there on, the storm will start to curve and accelerate toward the northeast. The current forecast takes Fiona on a relatively close pass to Bermuda later on 22 September and into 23 September, Verisk said.

A magnitude 6.9 earthquake struck Taiwan on 18 September, leading to reports of a building collapse, a landslide, a bridge failure, and more than 100 injuries. The quake was centreed near the township of Chishang, in Taitung county, which is in southeastern Taiwan, at a depth of 10 km. It was preceded by a magnitude 6.5 event several hours prior, and dozens of aftershocks, one reaching 5.9 in magnitude, have occurred since.

“The location, preliminary fault mechanism, and aftershock activity indicates that this earthquake (sequence) most likely occurred as a result of the Longitudinal Valley fault (LVF) movement,” Verisk said.

LVF is the major active fault in Taiwan taking up much of the plate motion between the Philippine Sea plate and Eurasian plate in this collision zone.

Much of the reported damage so far has been north of the quake’s epicentre, Verisk noted.

Verisk, hurricane, earthquake, typhoon, climate change

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