Typhoon Matsa

Typhoon Matsa, known in the Philippines as Typhoon Gorio, was the second of eight Pacific tropical cyclones to make landfall on China during the 2005 Pacific typhoon season. The ninth tropical storm and fifth typhoon of the season, Matsa developed on July 30 to the east of the Philippines. Matsa intensified as it tracked northwestward, and attained peak 10-minute sustained winds of 150 km/h (93 mph) near Taiwan before weakening and striking the Chinese province of Zhejiang on August 5. The system continued northward into the Yellow Sea, and on August 7 Matsa became extratropical after again moving ashore along the Liaodong Peninsula. Matsa is a Laotian name for a lady fish.

In Taiwan, Matsa dropped torrential rainfall of up to 1,270 mm (50 in), which caused mudslides and moderate damage across the island. Flooding from the rainfall contaminated some water supplies, leaving around 80,000 homes without water at one point; much of Taoyuan County (now Taoyuan City) was without water for at least 5 days. As in Taiwan, the typhoon dropped heavy precipitation in the People's Republic of China, and in combination with strong winds destroyed about 59,000 houses and damaged more than 20,000 km² (7,700 sq mi) of croplands. Throughout the country, Matsa caused 25 direct fatalities and ¥18 billion (2005 CNY, $2.23 billion 2005 USD) in damage.

The origin of Typhoon Matsa is traced to the formation of an area of convection about 185 km (115 mi) east of Yap in late July. The convection gradually consolidated over a weak low-level circulation, and at 0300 UTC on July 30 the system was first mentioned in the Joint Typhoon Warning Center (JTWC) Significant Tropical Weather Outlook. Located within an area of moderate wind shear, the system continued to slowly organize, and by 1200 UTC on July 30 it was sufficiently organized for the Japan Meteorological Agency (JMA) to classify it as a weak tropical depression while located about 65 km (40 mi) east of Yap. Shortly thereafter, the JTWC followed suit by issuing a tropical cyclone formation alert. The depression tracked steadily westward, followed by a turn to the northwest on July 31 under the influence of a mid-level ridge to its east. It continued to organize, and at 1200 UTC on July 31 it intensified into Tropical Storm Matsa; the depression was unofficially classified a tropical storm six hours earlier by the JTWC. Additionally, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) named the system Tropical Storm Gorio, due to its location within the administration's area of responsibility.

Tropical Storm Matsa gradually intensified as it tracked steadily northwestward; by late on August 1 it strengthened into a severe tropical storm. Outflow and deep convection to the north remained limited, though the storm was able to intensity further to attain typhoon status on August 2 about 780 km (480 mi) south of Okinawa. Intensification slowed, and late on August 3 Matsa reached a peak intensity of 150 km/h (93 mph) while located 495 km (308 mi) east of the southern tip of Taiwan as reported by the JMA; the JTWC and the National Meteorological Center of China reported the typhoon as strengthening further to attain peak winds of 165 km/h (103 mph) on August 4. Shortly after passing over the Japanese island of Ishigaki, Matsa began to weaken steadily as it approached the coast of China, and made landfall as a minimal typhoon late on August 5 near Yuhuan in the southern region of Zhejiang Province. It crossed the Gulf of Yueqing and 40 minutes after its first landfall it struck Mainland China near Yueqing. It quickly weakened to a tropical storm, and within hours of moving ashore the JTWC issued its last advisory. Matsa turned to the north, weakening to a tropical depression on August 7 shortly before entering the Yellow Sea. The weakening depression continued northward, and became an extratropical cyclone on August 9 after hitting the Liaodong Peninsula.

The Taiwan Central Weather Bureau warned for the potential for heavy amounts of rainfall across the island. This resulted in officials to close schools and offices in Taipei. Additionally, the typhoon caused the cancellation or delay of several flights in and out of Taipei, though complete air service was restored by the day after Matsa's passage. The Taiwan Stock Exchange closed due to the threat of the typhoon.

Prior to the arrival of the typhoon, officials in China ordered the evacuation of about 2.3 million people, mostly in Zhejiang. The typhoon also resulted in the cancellation or delay of thousands of flights, with the two main airports in Shanghai closed for 30 hours. Officials near Matsa's projected landfall were advised to lower the levels in reservoirs to mitigate the threat of flooding. In Zhejiang, officials set up shelters for about 35,000 boats to prevent marine damage. Due to the potential for rough seas, officials closed the port at Ningbo and Shanghai and also canceled some ferry service. Matsa was predicted to be first typhoon to affect Beijing in 11 years by dropping heavy amounts of rainfall. Local officials advised water operators to lower water levels to prevent flooding. Up to 100 mm (3.9 in) of rainfall was forecast for the city, and officials prepared to evacuate 40,000 residents in the outskirts of the city.

While passing to the north of Taiwan, Matsa produced strong winds reaching 144 km/h (89 mph), with gusts of up to 188 km/h (117 mph). The storm dropped heavy rainfall across the island, with precipitation totals reaching up to 1,270 mm (50 in) in a 30‑hour period; one station located in Taitung County recorded 843 mm (33.2 in) in one day, which was the highest daily rainfall total in association with the storm. The rainfall led to flooding and mudslides throughout the island. In response to the flooding, residents placed sandbags around houses and office buildings to prevent flood damage. The mudslides blocked roads across the mountainous region, leaving hundreds stranded, and in combination with flooding the mudslides washed away several bridges and damaged some roadways. Strong winds left 56,211 houses without power, most of which were quickly repaired. Typhoon Matsa caused moderate crop damage across the island, which was still recovering from the damage caused by Typhoon Haitang a month before. More than 80,000 homes were left without water due to the passage of the typhoon. Subsequent flooding left more than 630,000 homes without water or receiving water at infrequent intervals. About 368 hectares (910 acres) of crop fields were destroyed, and crop damage from Matsa totaled NT$47 million (2005 TWD, $1.5 million 2005 USD). According to the Taiwan Council of Agriculture, the banana and pear crops were the worst affected.

Upon making landfall in China, several coastal locations reported winds in excess of 120 km/h (75 mph), with wind gusts peaking at 175 km/h (109 mph). Further inland, winds reached 147 km/h (91 mph) at Shanghai, the highest wind gust on record in the city. The storm produced heavy amounts of rainfall, reaching a maximum of 701 mm (27.6 in) at a station in Yongjia County. Extreme amounts of precipitation fell in short durations, including 91 mm (3.6 in) in just 1 hour and 200 mm (7.9 in) in 3 hours at Dinghai District. Just days after a previous heavy rainfall event, the rainfall from Matsa caused record-breaking river flooding along eight Chinese rivers, including a station at a floodgate on Suzhou Creek which peaked at 4.55 m (14.9 ft).