Weakened Typhoon Danas in Korea Strait, Sea of Japan: AIR Worldwide

According to catastrophe modeling firm AIR Worldwide, after pounding Okinawa with the outer reaches of its 184 km/h [114 mph] winds Monday evening local time, Typhoon Danas has weakened to tropical storm strength and it is passing through the Korea Strait into the cooler waters of the Sea of Japan, where it is expected to weaken further.

As of the Japan Meteorological Agency’s (JMA) 1700 UTC analysis today (2 a.m. local time), Tropical Storm Danas had maximum 10-minute sustained winds of 92 km/h [57 mph] with gusts up to 130 km/h [80.7 mph]. Danas’ center was located about mid-way in the Korea Strait about 240 km [149 miles] from the city of Hiroshima in Japan and 100 km [62 miles] from Busan in South Korea. Danas’ tropical storm force winds extend outward about 110 km [68.3 miles] to the northeast and 60 km [37 miles] to the southwest. It is currently moving to the northeast at about 35 km/h [21.7 mph].

“Tropical Storm Danas began as a tropical depression northeast of Guam on October 3 and became a tropical storm late the next day,” said Dr. Peter Sousounis, senior principal scientist, AIR Worldwide. “Even as Danas passed just north of Okinawa on October 7, it maintained its strong winds of 184 km/h (10-minute sustained)—a Category 4 storm on the Saffir-Simpson Hurricane Wind Scale.

“Typhoon Danas arrived at the island prefectures of Okinawa and Kagoshima on the heels of Typhoon Fitow, which impacted the region just three days earlier. After leaving Okinawa, Danas weakened to Category 1 status as it approached the Korea Strait, and it has since weakened further.”

AIR said “minimal structural damage from wind is expected from Tropical Storm Danas once it makes landfall in northern Honshu. In the countryside, wood frame homes dominate residential construction. Many have heavy, clay tile roofs meant to prevent damage from wind. At Danas’ forecast wind speeds, these buildings are expected to possibly have minor roof damage and little or no structural damage.

“Larger multi-family apartment buildings and commercial and industrial structures, are generally engineered and made of reinforced concrete or steel, making them even less vulnerable to Danas’ winds. Modern urban structures are similarly expected to experience little or no damage.”

According to AIR, any further damage from Danas is expected to be “from heavy precipitation and the effects of flooding and mudslides, mostly in the relatively circumscribed northern part of Honshu—Tohoku—where Danas is now expected to make landfall”.

Dr. Sousounis added: “At Okinawa, the two typhoons in three days, Fitow and Danas, dropped as much as 23 centimeters [app. 9 inches] of rain on the island. No significant damage has been reported, however.”

Throughout the region, about 30,000 homes lost power. Danas is only the fourth “October Typhoon” to affect Korea since 1950; the last October typhoon was in 1998. As Danas approached the Korea Strait, China issued an Orange alert for its nearby coastal region, the second highest warning level for waves.

Dr. Sousounis concluded: “The 24th typhoon of the current Northwest Pacific tropical cyclone season, Danas became the fourth strongest tropical cyclone to develop anywhere this year when it reached Category 4 status.

“Prior to Danas entering the Korea Strait, however, it began to experience shear to its north. The system also began undergoing extratropical transition. As Danas leaves the Strait it will encounter more shear and even cooler sea surface temperatures. It is forecast to become embedded within a mid-latitude trough and complete its extratropical transition in the next 24 hours. It is then that Danas is forecast to make landfall in northern Honshu and then emerge back over the Pacific Ocean. Danas continues to produce heavy rainfall, which is the main impact expected from the storm.”

Source: AIR Worldwide