Taiwan storm intensifies to typhoon level in 48 hours: AIR

Typhoon Nepartak, which formed to the south of Guam, has rapidly strengthened, according to catastrophe modeling firm AIR Worldwide.

Nepartak is the first named storm in the western North Pacific basin since mid-December 2015, setting a new record for the longest period (200 days) without tropical storm in the basin in 66 years.

Christopher Bednarczyk, scientist at AIR Worldwide, said that the transformation from storm to typhoon had been rapid and intense and had happened in 48 hours. He also warned that it was equivalent to a category 4 hurricane on the Saffir-Simpson scale with maximum sustained winds of 216 kilometers an hour (134 miles per hour) and a minimum central pressure of 900mb.

Bednarczyk said that the typhoon was in an area of high ocean heat content and low vertical wind shear, which had contributed to its rapid intensification.

He added: “Satellite imagery shows a clearly defined eye and good upper-level outflow. It is expected to make landfall early Friday before turning northward toward eastern China. The Northwest Pacific Basin produces more tropical cyclones each year than anywhere else in the world.”

Bedarczyk suggested that on average, this basin produces 29 tropical cyclones each year, where 20 of these reach typhoon status. He says that the “extremely large expanse” of very warm water temperatures in the basin could be one of the contributing factors to this statistic.

According to the scientist, Taiwan experiences the third-highest number of land falling tropical cyclones every year compared with other Southeast Asian countries. On average, two cyclones occur in Taiwan each year and the Philippines receives the highest number, while Vietnam experiences the second-highest number of cyclones.

The severity of the natural disaster will be reduced by the steep elevation along the island’s east coast. It is expected to cause flooding, landslides, wind-borne debris, coastal flooding and damage or interruption to the infrastructure such as power and transportation systems.

The mountainous terrain movement is expected to weaken the typhoon before it moves northward, which would make a potential second landfall in eastern China on Saturday. However, the risk level in the location and intensity of the possible impact on China is still considerably uncertain.

AIR suggests that while high winds usually cause the most cyclone damage in other parts of the world, rain-induced flooding often causes the most damage in the Northwest Pacific Basin.

While tropical cyclones usually become weaker as they interact with the central mountain range in Taiwan and the eastern coast of the island is relatively under populated, heavy wind losses tend to be limited to the east cost of the island. This includes areas of Taitung and Hualien.

Strictly enforced building codes throughout the nation have resulted in structures with generally good wind resistance.

The country faces a serious threat from flooding, particularly along the southwestern mountains due to orographic lifting combined with occasional South China Sea monsoon-scale influences. In the past, heavy flood damage has occurred to the heavily urbanized areas of Taipei and Kaohsiung during typhoons, including Typhoons Nari (2001) and Morakot (2009).