Typhoon Nanmadol winds weakened, impacts seen largely from rainfall

Typhoon Nanmadol made landfall in southwest Japan in the Kagoshima region of Kyushu yesterday. While winds were reported as high as 150 mph, in terms of gusts, Nanmadol noticeably weakened, with rainfall, flooding and landslides appearing the main threats.

Some wind related damage has been experienced in Kyushu, particularly in the region closest to landfall, but at this time it appears to have been far less than had been anticipated.

The Japanese Meteorological Agency had warned that typhoon Nanmadol could be historic, with the storm said likely to be among the strongest to ever impact Japan.

As a result, they also likened its potential for causing damage and disruption to two more recent typhoons, Jebi and Hagibis, both of which were significant insurance and reinsurance market loss events.

The threat to insurance and reinsurance markets from wind-related property damage caused by typhoon Nanmadol appears greatly lessened, as the typhoon has weakened considerably now.

However, with rainfall totals as high as 700 mm reported from the storm and high levels of rain anticipated for much of Japan as Nanmadol travels along its length, the flood threat is severe and likely to be the main damage component of any insurance or reinsurance industry loss associated with the typhoon.

Damage is likely to be worst in the southwest and in Kyushu cities like Nagasaki and Fukuoka lost a significant percentage of their power, while flooding and landslides have been seen to cause property damage.

Overall it appears the forecasts for a more prolonged typhoon strength wind event that affected a significant proportion of Japan’s Honshu island as well now looks unlikely, meaning the industry loss potential from Nanmadol is likely reduced.

It’s far too early for any loss estimates to come out, but given the weakening seen and more limited scope of the anticipated damage, it seems unlikely Nanmadol will drive a particularly significant impact for the reinsurance market at this time and once any figures are available the main component could be water-driven rather than wind.

Nanmadol will still track much of the length of Japan, weakening as it goes, but dropping rainfall as well. However, with the storm track having shifted north the heaviest rains may now not impact the most populated areas of Honshu island.

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Update: Some reinsurance layers are expected to attach on the back of losses from typhoon Nanmadol.