2001 Pacific typhoon season

A busy year in a neutral Pacific

The season unfolded as a weak La Niña faded early in 2001 and the tropical Pacific settled into near-neutral conditions for the rest of the year. Tropical Storm Risk had expected close to average activity, forecasting about 26 to 28 tropical storms and 16 to 18 typhoons. By the archive's count the basin produced 29 tropical storms and 20 typhoons, with 11 reaching major strength and an accumulated cyclone energy of 306.4, so intense typhoons were a defining feature of the year.

Agency totals differ because each counts in its own way. The Japan Meteorological Agency, the official regional centre, uses ten-minute average winds and named 26 storms, 16 of which it classed as typhoons. The Joint Typhoon Warning Center, whose one-minute winds are closer to the archive's definition, tallied 30 tropical storms and 20 typhoons from its own warnings. The archive counts from the reanalysed US-agency best track over the calendar year, so systems such as late-year tropical storms that the Japanese agency never named are included here.

How the season unfolded

The first tropical-stage observation came on 16 February, when a depression crossed the central Philippines and dissipated in the South China Sea. Rain from the system set off landslides on Mindanao, where news reports cited by the Joint Typhoon Warning Center put the toll at 17 deaths, and a further 10 people died when a passenger boat sank in rough seas off Tawi-Tawi. After another weak depression in April, Tropical Storm Cimaron became the first named storm in May, passing near Okinawa without reported casualties.

The season came alive in late June. Typhoon Chebi became the first typhoon on 22 June, and within a month the basin had produced Durian, Utor, Trami, Kong-Rey, Yutu and Toraji, most of them tracking toward the Philippines, Taiwan and southern China. August and September brought the densest run of storms, including Man-Yi, Pabuk, Wutip, Danas, Nari, Vipa, Francisco and Lekima, several of which curved north toward Japan or recurved over open water.

Activity eased but did not stop in the autumn. Krosa, Haiyan and Podul formed in October, Lingling crossed the central Philippines in November, and December produced Tropical Storm Kajiki, the short-lived Tropical Storm 31W, Typhoon Faxai and finally Typhoon Vamei, whose track continued into the first day of 2002.

The strongest typhoons

Typhoon Faxai was the season's strongest storm. It lingered almost stationary near Kosrae for about five days in mid-December before moving northwest and intensifying rapidly, reaching one-minute winds of 155 kt and a central pressure of 879 hPa on 23 December. Typhoon Podul, the other Category 5 storm, peaked at 140 kt on 24 October during a track that stayed entirely over the ocean as it moved north from near Pohnpei.

Several other typhoons came close. Typhoon Wutip strengthened from 45 kt to 120 kt in 36 hours and peaked at 130 kt on 29 August, the first storm the Joint Typhoon Warning Center classed as a super typhoon that year. Typhoon Man-Yi went through a similar burst in early August, reaching 120 kt before an eyewall replacement cycle, and Typhoon Lingling intensified rapidly in the South China Sea to 115 kt on 10 November.

Taiwan and southern China in the firing line

Taiwan bore the brunt of the season. Typhoon Toraji crossed the east of the island on 29 July, and Taiwan's Central News Agency reported 72 deaths from its torrential rain and mudslides, making it the deadliest typhoon on the island since 1961 by that count. In one Nantou County village buried by mud and rock, at least 30 people died, and Taiwan's premier afterwards blamed overdevelopment and launched a reforestation effort.

Typhoon Nari was the longest-lived storm of the year, with a track spanning 5 to 21 September. It traced three cyclonic loops west of Okinawa and peaked at 100 kt before turning southwest and striking northeastern Taiwan on 16 September. Taiwan's Central Weather Bureau reported up to 800 mm of rain in a single day, the island's greatest on record, and BBC reporting cited by the Joint Typhoon Warning Center put the toll at no fewer than 66 deaths, with 650,000 households losing power and water. Later in the month Typhoon Lekima crossed southern Taiwan, the eighth tropical cyclone to hit the island that year by the Joint Typhoon Warning Center's count.

Southern China took a series of blows in early summer. Typhoon Chebi made landfall in Fujian on 23 June after rapidly strengthening southwest of Taiwan; the China News Service reported at least 73 deaths, 83 people missing and US$422 million in damage in 2001 dollars, while at least nine people died in southern Taiwan. Typhoon Durian struck southern China on 2 July, with China's Meteorological Administration reporting 65 people killed or missing, and it went on to cause northern Vietnam's worst flooding in 40 years. Typhoon Utor, a very large storm, killed 121 people in the Philippines according to the Philippine government and 23 in Guangdong according to Xinhua, where damage was estimated at US$286 million in 2001 dollars.

Floods in Thailand, the Philippines and Japan

Tropical Storm Usagi was weak when it came ashore in Vietnam on 10 August, but its rain caused deadly flash floods in northern Thailand, where the Thai Meteorological Department reported up to 177 deaths. Mudslides in the deforested hills of Phetchabun province, especially Lom Sak district, accounted for many of them.

In November, Typhoon Lingling moved slowly over the central Philippines as a weak system and drenched the island of Camiguin, where news reports put the toll at 171 confirmed dead and 118 missing. It then strengthened in the South China Sea and struck central Vietnam near Qui Nhon, where 18 deaths were reported.

Japan faced two landfalling typhoons. Typhoon Pabuk came ashore in Wakayama Prefecture on 21 August, and the Japan Meteorological Agency reported eight deaths. Typhoon Danas struck near Yokosuka on 11 September and moved over Tokyo, with up to 895 mm of rain in the Kanto region; officials reported six deaths and 45 injuries, and the storm also spawned an F1 tornado near Tokyo.

A remarkable December

Faxai's slow start brought heavy rain to Kosrae, where an indirect death was reported and power was cut. As the typhoon later recurved near the Northern Mariana Islands, its swells reached Guam, where a man drowned in rip currents at Gun Beach on 22 December. Damage across the affected islands was estimated at about US$1 million in 2001 dollars.

Typhoon Vamei formed only about 1.5 degrees north of the equator east of Singapore, a latitude at which tropical cyclones almost never develop. Naval ship observations inside its small eyewall led the Joint Typhoon Warning Center to classify it as a typhoon on 27 December, shortly before it made landfall in Malaysia northeast of Singapore. A landslide at Gunung Pulai killed five people, and Malaysian flood damage was put at RM13.7 million (about US$3.6 million in 2001). Post-analysis found that Vamei crossed into the Bay of Bengal and briefly regenerated there.

Names and forecasting milestones

2001 was the first year for the current international naming list, and all 26 names were used for the first time. The Typhoon Committee later retired Vamei, replacing it with Peipah, and the spelling of Vipa was corrected to Wipha. In the Philippines, PAGASA retired Nanang, its local name for Lingling. Agency peaks also differ by definition: the Japan Meteorological Agency gave Faxai ten-minute winds of 105 kt and a pressure of 915 hPa, compared with the archive's one-minute 155 kt and 879 hPa.

For the Joint Typhoon Warning Center the year was a milestone in forecast accuracy, completing three consecutive record-breaking years. Its mean track errors were 73, 122 and 180 nautical miles at 24, 48 and 72 hours, its best performance in 43 years of operation, which it credited to consensus forecasting, while 72-hour intensity errors fell by 17 percent from 2000.