2007 Pacific typhoon season

A below-normal year

The site's archive tracks 27 systems in the western Pacific during 2007, with an accumulated cyclone energy of 214.2. The Joint Typhoon Warning Center (JTWC) also counted 27 tropical cyclones, against an average of about 31 per year since 1959, and described the year as a continuation of below-normal activity in the basin. Energy was well short of the long-term average of 305 cited by Tropical Storm Risk, whose seasonal forecasts had ranged from about 15 percent below normal in March to near normal by midsummer.

Early in the year the Philippine weather agency PAGASA pointed to a weak El Niño and expected no tropical cyclone to enter its area of responsibility before May. That held: the first storm it named was Typhoon Yutu, called Amang locally, which crossed into the Philippine area on May 18.

How the season unfolded

Typhoon Kong-Rey opened the season on March 30 and became its first typhoon on April 2, passing through the Northern Mariana Islands before turning northeast and losing its tropical character. Typhoon Yutu followed in mid-May, recurving past Iwo Jima after a burst of rapid strengthening. No tropical storm formed in June, and the season did not pick up until July, when Tropical Storm Toraji crossed Hainan into northern Vietnam, Typhoon Man-Yi raked Okinawa and southern Japan, and Typhoon Usagi came ashore on Kyushu.

August and September carried the main run of the season. Typhoon Pabuk crossed southern Taiwan and meandered near Hong Kong, Typhoon Sepat became the year's strongest storm, and Typhoon Fitow came ashore near Tokyo in early September. Typhoon Nari and Typhoon Wipha then intensified quickly in mid-September, and Tropical Storm Francisco crossed Hainan before the month ended.

October brought Typhoon Lekima into Vietnam and Typhoon Krosa into Taiwan and China, while Typhoon Kajiki peaked over the open ocean near Iwo Jima. November was unusually crowded: JTWC recorded six tropical cyclones that month, about twice its long-term November average, including Typhoon Peipah, Typhoon Hagibis and Typhoon Mitag, all of which crossed the Philippines. The archive's last tropical observation is on November 28.

The strongest storms

Typhoon Sepat was the only Category 5 storm of the year, reaching one-minute winds of 140 kt and a pressure of 918 hPa on August 15. It weakened through an eyewall replacement cycle before making landfall on eastern Taiwan late on August 17 UTC, then crossed the Taiwan Strait to strike China near Quanzhou about a day later. The Japan Meteorological Agency (JMA) analyzed a lower central pressure of 910 hPa.

Eight more storms reached major typhoon strength. Typhoon Wipha peaked at 135 kt on September 18 before landfall near Wenzhou, China, and Typhoon Yutu and Typhoon Krosa each reached 130 kt. Typhoon Man-Yi and Typhoon Nari peaked at 125 kt, Typhoon Usagi at 120 kt, Typhoon Kajiki at 115 kt and Typhoon Kong-Rey at 100 kt. Man-Yi also had the longest record of the year, tracked for 396 hours from early July until its remnants faded.

Krosa stood out to forecasters. JTWC found that it strengthened by 40 kt a day for two days in a row, growing from a 25 kt depression to a 100 kt typhoon between October 1 and 3, a pace its intensity guidance failed to capture. Its track forecasts were accurate, but intensity was badly underforecast, and JTWC cited the storm as a reason to refocus on intensity prediction.

Landfalls and impacts

Southeast Asia suffered the heaviest losses. A tropical depression numbered 06W by JTWC meandered off Vietnam in early August, and flooding there killed at least 60 people; its remnants caused two deaths and damage of about US$7.5 million (2007 dollars) in Thailand. Typhoon Lekima crossed Luzon, where a landslide in Ifugao Province killed eight, and then struck Vietnam near Dong Hoi on October 3, where 88 people were killed and 8 left missing.

China faced two major threats within a month. Nearly 2 million people were evacuated from Shanghai, Zhejiang and Fujian ahead of Typhoon Wipha, which killed nine people and caused damage estimated at more than US$880 million (2007 dollars). Typhoon Krosa injured at least 17 people in Taiwan in early October, and 730,000 people were ordered to evacuate from Zhejiang and Fujian as it approached the mainland.

In Japan and Korea, Typhoon Fitow killed seven people and disrupted transport around Tokyo, and Typhoon Man-Yi injured 37 people on Okinawa after high seas capsized a ship northwest of Guam, killing three with six missing. Typhoon Nari reached South Korea near Yeosu at tropical storm strength; its rain set a record of 590 mm on Jeju, and at least 20 people were killed or missing in the flooding.

The Philippines saw repeated flooding. Typhoon Pabuk was blamed for at least 11 deaths there, and Tropical Depression Wutip killed six people and caused PHP16.8 million (about US$349,000 in 2007) in damage. Sepat enhanced the monsoon over Metro Manila without making landfall. In November, Typhoon Hagibis killed nine people in the Visayas and Mindanao, and ten deaths were attributed to Typhoon Mitag, known locally as Mina, after some 200,000 people were evacuated from the Bicol Region.

Unusual tracks and how agencies counted

Typhoon Hagibis followed one of the year's oddest paths. It formed over the southern Philippines and moved west into the South China Sea, then stalled east of Vietnam when a midlatitude trough weakened the ridge steering it. Equatorial westerlies pushed it back east to the Philippines, and JTWC, which had forecast a landfall in Vietnam, recorded its largest track error of the year, 658 nautical miles at 72 hours.

Tropical Storm Haiyan was a late addition. It began as a midlatitude low northeast of Wake Island and was first assessed as subtropical, but post-season analysis of satellite data showed it had become a warm-core tropical storm with an apparent eye, peaking at 50 kt on October 5. JTWC never issued warnings on it and added it to its database afterward as 27W.

JMA named 24 tropical storms and counted 14 typhoons using ten-minute winds, which run lower than the one-minute winds behind the site's figures. That is why Typhoon Danas and Typhoon Lekima, which reached typhoon strength on one-minute winds, stayed severe tropical storms for JMA. JMA's count is higher on tropical storms because it named Wutip and Podul, which the US-agency record does not take to 34 kt, and Lingling, which formed near the date line and is not in this map's storm list. JTWC's four super typhoons, Yutu, Sepat, Wipha and Krosa at 130 kt or more, include three that fell short of the 137 kt Category 5 threshold.

The name Peipah was used for the first time in 2007, having replaced Vamei on the international list, and no names were retired after the season.