TOKYO - A powerful typhoon churning toward Japan's Okinawa islands strengthened by Friday to a Class Five storm -- technically the same strength as Hurricane Katrina, which devastated New Orleans -- and experts said it could also threaten Japan's southernmost main island.
Typhoon Nabi -- Korean for "butterfly" -- increasedin power to super-typhoon status, the Tropical Storm Risk group at University College London said on its website, www.tropicalstormrisk.com
An official at Japan's Meteorological Agency warned that the storm could reach Okinawa by Monday and could curve up to hit Japan's southernmost main island of Kyushu.
Nabi was expected to increase its windspeed enough to be dubbed "violent", the strongest designation Japan uses for typhoons, by Saturday morning.
"It is an extremely dangerous storm, and there is the potential for quite a bit of damage," he said.
But cooler ocean temperatures near Japan mean Nabi is unlikely to have the same destructive power as Katrina, while strong prevailing winds are likely to help dissipate its force relatively rapidly once it approaches.
"The storm will be strongest when it is out over the open ocean, and by the time it nears any part of Japan it should have weakened a bit," he added.
As of 9am NZT on Friday, Nabi, with winds near its centre of around 180 km/h, was about 250 km southeast of Okinotorishima, a rocky islet 1700 km south of Tokyo.
Katrina, by comparison, struck the US Gulf Coast with winds of 225 km/h.
Nabi was moving north-northwest around 20 km/h, a speed and course that, if unchanged, would put it on track to hit Okinawa by Monday or Tuesday.
Okinawa, a string of islands with a population of 1.36 million, is regularly hit by typhoons.
