A super typhoon is headed for Hong Kong: here’s what you need to know

Happy mid-Autumn festival, everybody!
Happy mid-Autumn festival, everybody!
Image: NOAA
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An atmospheric monster has blossomed in the western Pacific Ocean, and it could have a devastating impact on Hong Kong this weekend.

On Thursday, Super Typhoon Usagi—now officially Earth’s strongest storm this year—rapidly grew from tropical storm strength to the equivalent of a category five hurricane, the scale’s highest level. That transformation occurred in an impressively short period of time: the storm’s estimated winds increased in speed by about 85mph (140kph) in less than a day—good enough for one of the fastest intensification rates ever recorded. Maximum wind gusts within Usagi are now estimated to be an incredible 170 knots (see below), or 195 mph (315 kph).

And it may be even stronger than that. Unlike in the Atlantic Ocean, there are no direct ‘hurricane hunter‘-style aircraft observations of typhoons in the Pacific, so we don’t really know how strong this mega-storm is. One satellite-based estimate shows the storm’s minimum central pressure to be around 882 millibars, good enough to be the planet’s strongest storm since 1984.

The Joint Typhoon Warning Center, a US Military forecasting command post in Pearl Harbor, Hawaii, said there is “high confidence” that the track of Usagi will skirt the southern tip of Taiwan on Friday and make landfall near Hong Kong late Saturday. The storm is gathering in the Pacific as Hong Kong, mainland China, and much of Asia, celebrates the mid-Autumn festival, a time when far-flung families gather and neighborhoods host outdoor carnivals.

Usagi, which means “rabbit” in Japanese, is forecast to weaken slightly on its path over the next day or two. However, it will still cause heavy rains as the storm’s outer bands hit the mountains of central Taiwan. The island’s Central Weather Bureau has issued an ‘Extremely Torrential Rain Advisory’ for many of its southern and eastern counties. Huge, 12 meter (~35 foot) waves may also strike Taiwan’s east coast on Friday, along with destructive storm surge.

China’s National Meteorological Center also issued a Yellow Alert on Thursday (it’s third highest) in advance of anticipated impacts on the mainland later in the weekend. If the storm makes a direct hit in Hong Kong, it would be the first time the city has suffered consecutive Signal 10 warning typhoon strikes in more than 50 years, since 1960-62.