Typhoons Saola, Damrey Strike, Philippines, Taiwan, China: AIR Analysis

According to catastrophe modeling firm AIR Worldwide, Typhoon Saola, the ninth typhoon of the Northwest Pacific storm season, made its first landfall early Thursday morning local time in Hualien, Taiwan.

AIR noted that the storm has since “been downgraded to a tropical storm, with maximum 1-minute sustained wind speeds of 106 km/h (66 mph) and is poised to strike near the border between Fujian and Zhejiang province late Thursday night or early Friday morning, local time.”

Dr. Peter Sousounis, senior principal atmospheric scientist at AIR Worldwide, indicated that “damage from Saola’s winds is expected to be minimal to well-constructed buildings in China. There may be instances of roof and wall cladding damage to poorly built structures, including masonry dwellings (which dominate China’s residential building stock) and non-engineered commercial structures. The main concern remains precipitation-induced flooding, as rainfall of up to 400 mm [app. 15 ¾ inches] is forecast in coastal regions.”

In the Philippines, Saola (locally known as Typhoon Gener) brought torrential downpours earlier this week forcing 154,000 to evacuate their homes. The storm tracked slowly just north of the Taiwan after its brief landfall. The Central Weather Bureau in Taipei reported more than 800 mm [app. 31 ½ inches] of accumulated rainfall from Tuesday to the present at 35 stations in northern and central portions of Taiwan. The city of Taipei has reported about 355 mm [app. 14 inches] of precipitation. Anticipating high water levels, administrators at Taiwan’s seven major reservoirs have released water to mitigate flooding.

Dr. Sousounis noted: “Saola has flooded homes, business, and vast expanses of farmland in Taiwan. Mudslides in mountainous regions have shut down roads, and high winds have toppled trees onto cars and buildings. Heavy rains are expected to continue into the night in Taiwan, easing by midday Friday.”

China’s Central Meteorological Administration has issued a red warning for typhoon, the first such warning for this year. After its projected landfall at tropical storm strength, Saola is expected to move into Jiangxi province.

Meanwhile, Typhoon Damrey has made landfall along China’s coast farther to the north than Saola. Damrey is the tenth typhoon of the season and hit northern Jiangsu province with maximum 1-minute sustained wind speeds of 150 km/h (93 mph, or a strong Category 1 hurricane on the Saffir-Simpson scale), according to the Japan Meteorological Agency’s 15:45 UTC advisory. It is moving to the west-northwest with a forward speed of 25 km/h.

Dr. Sousounis commented: “At this time of year, typhoons that form near where Damrey did typically make landfall in southern Japan or Korea. However, a strong blocking ridge of high pressure, along with the counter-clockwise pull from the larger Saola, has tracked Damrey farther to the south. The storm is not expected to affect Shanghai, China’s largest city, which is some 400 km (250 miles) to the south of Damrey’s forecast landfall location.”

According to AIR, the storm is expected to turn to the northwest into Shangdong province and approach Hebei province farther to the north, where it is expected to dissipate on Saturday. Because of Damrey’s compact size, effects of its rainfall are expected to be less severe than Tropical Storm Saola. Precipitation of up to 250 mm [9.85 inches] is forecast by the China Meteorological Administration. At its wind speeds at landfall, Damrey is expected to cause minor damage to roof and wall claddings and damage is expected to trees, utility poles, and signage. A red warning for typhoon is in effect.

Source: AIR Worldwide