Super Typhoon Usagi,the equivalent of a Category 5 Atlantic hurricane, intensified rapidly Thursday in the western Pacific Ocean and will threaten parts of Taiwan, the far northern Philippines and southern China through the next several days.

Image
A tropical cyclone is dubbed a "super typhoon" when maximum sustained winds reach at least 150 mph. Usagi underwent a period of rapid intensification from early Wednesday through midday Thursday (U.S. Eastern time), going from a 55-knot tropical storm to a 140-knot super typhoon in just 33 hours, or just under a 100 mph intensification, based on satellite estimates of intensity.

Usagi is expected to maintain a west-northwest path through the weekend. Here are the potential forecast impacts by location for Usagi:

Taiwan
  • Closest approach of center of Usagi: Saturday afternoon, local time.
  • The most likely path for the center of Usagi is to pass near the southern tip of Taiwan at that time. This would put Taiwan in the most dangerous eastern semicircle of Usagi.
  • Potential impacts: Surge flooding/battering waves (eastern coast especially), damaging winds (particularly southern Taiwan), flooding rain/mudslides (central, eastern Taiwan).
  • Local forecast: Taipei
Northern Philippines
  • The center of Usagi will likely pass north of the north coast of Luzon from late Friday into Saturday, local time.
  • Potential impacts: Coastal flooding/high surf along the north coast of Luzon, bands of locally heavy rain (trigger flash flooding/mudslides), some wind damage possible.
  • Local forecast: Manila
Hong Kong
  • Closest approach of center of Usagi: Sunday evening/night, local time.
  • Current forecast anticipates Usagi will weaken before reaching southern China, but still may be a Category 1, 2 or 3 equivalent system.
  • Potential impacts: These will depend on exact track of Usagi's center Sunday. It is still too soon to forecast these impacts.
  • Local forecast: Hong Kong
Incidentally, Hong Kong is one of the most densely populated places in the world, with over 7.1 million residents, as of a 2012 estimate.