1997 Pacific typhoon season

The year of the super typhoon

The Joint Typhoon Warning Center counted 33 significant tropical cyclones in the western North Pacific in 1997, close to its average of 32. What set the year apart was intensity. Eleven storms reached its super typhoon threshold of 130 kt, against a 37-year average of four and a previous record of seven, and the center's staff called 1997 the year of the super typhoon. Its calendar-year total of 23 typhoons was the highest since 1971.

The site's archive counts 28 tropical storms, 20 typhoons, 10 major typhoons and 8 Category 5 storms, with an accumulated cyclone energy of 460.1 from US-agency one-minute winds during the tropical stage. The JTWC totals of 31 tropical storms and 23 typhoons include Oliwa and Paka, which formed in the central Pacific and crossed the date line, and the small Tropical Storm Ella, which also started east of the date line; none of the three appears in the site's list for this basin. Counting Oliwa and Paka, other season lists describe ten Category 5 storms, and Colorado State University calculated an ACE of 570.4 from JTWC data, the highest on record for any season.

The JTWC tied most of the year's traits to one of the strongest El Niño events on record. Persistent low-level westerlies at low latitudes pushed the monsoon trough east into the Marshall Islands, and ten storms formed east of 160°E and south of 20°N. Starting that far east gave storms long, low-latitude paths over warm water, the mechanism the JTWC proposed for the rise in super typhoons. Tracks tilted north: 15 of the 33 systems recurved, few stayed in the South China Sea, and only one named storm, Ivan, struck the Philippines.

An early start in the Marshall Islands

Tropical Storm Hannah formed south of the Marshall Islands in January, travelled west for over two weeks and peaked at 50 kt before dissipating in the Philippine Sea. The archive's first tropical-stage observation comes on 19 January. After a quiet February and March, a monsoon depression in the eastern Caroline Islands became Typhoon Isa, the first of the year's super typhoons. Isa passed south of Guam on 16 April with up to 250 mm of rain, then turned north and reached 145 kt on 20 April before recurving at sea.

Tropical Storm Levi crossed Luzon as a depression in late May and caused severe flooding in Metro Manila; it killed 53 people and displaced 210,000 in the Philippines. Typhoon Nestor then formed in the Marshall Islands, passed over the top of the Mariana chain and peaked at 140 kt on 10 June, about 200 nm northeast of Saipan. Typhoon Opal became the first storm of the year to strike Japan, in southern Honshu, and Typhoon Peter followed, crossing Kyushu and almost the full length of Honshu. Each storm killed three people in Japan.

Rosie in Japan and Winnie's giant eyewall

Typhoon Rosie formed south of Guam, reached 140 kt on 22 July and weakened before coming ashore near Okayama on 26 July as a minimal typhoon of 65 kt. The JTWC reported two deaths in Japan with power failures and landslides; it killed five people and displaced 1,200. Typhoon Victor, upgraded to a minimal typhoon after the season from landfall observations, struck near Hong Kong on 2 August, and the JTWC cited press reports of 49 deaths and 12,000 homes destroyed by flooding in Guangdong.

Typhoon Winnie formed in the Marshall Islands and reached 140 kt on 12 August in the archive. On its approach to Okinawa, a rainband wrapped fully around the eyewall and formed an outer eyewall nearly 200 nm across, one of the largest ever observed, where Doppler radar at Kadena measured 100 kt winds. Winnie passed north of Taiwan and came ashore south of Shanghai on 18 August as a Category 1 typhoon. The JTWC reported 27 deaths in Taiwan when an apartment building collapsed, 12 more from mudslides, floods and wind, and at least 25 in mainland China. Later totals give at least 372 deaths in all and over a million people displaced.

Late August stayed crowded. Typhoon Zita reached 75 kt over the Leizhou Peninsula and struck Vietnam on 23 August, and later totals give seven deaths. Typhoon Amber peaked at 110 kt just before striking Taiwan on 29 August after a binary interaction with Tropical Storm Cass, which it later absorbed over China. Typhoon Bing slipped between Guam and Rota as a tropical storm on 29 August, then deepened to 135 kt within 54 hours.

September storms from the date line

The eastward monsoon trough sent several September storms west from near the date line. Oliwa formed southwest of Hawaii, crossed into the basin on 4 September and deepened from 75 to 140 kt in 24 hours before striking southern Kyushu at 70 kt; the JTWC reported seven deaths on Kyushu and 28 ships sunk or wrecked along Korea's southern coast. Typhoon Ginger formed near the date line, deepened explosively and reached 145 kt on 27 September, then turned northeast. Its remnants brought gusts of 69 mph to the Oregon coast on 2 October.

In the South China Sea, Typhoon Fritz drifted east, turned back toward Vietnam and came ashore at 75 kt on 25 September. The JTWC cited at least 25 deaths and dozens missing in Vietnam, most of them gold prospectors buried by landslides; later totals give 28 deaths.

Ivan and Joan at 160 kt, side by side

An equatorial westerly wind burst in October preceded the formation of Ivan, Joan and a Southern Hemisphere twin. Typhoon Ivan passed 55 nm south of Guam and went from 65 kt to 160 kt between 15 and 17 October. Typhoon Joan formed just to the east, passed north of Guam and deepened from 70 to 160 kt in 36 hours. The JTWC called them the two most intense tropical cyclones ever seen at the same time. Both reached 160 kt and 905 hPa in the archive, with Ivan listed as the season's strongest storm, and Joan stayed above the super typhoon threshold for a record 4.5 days.

Ivan weakened before striking northern Luzon on 20 October, with landfall winds near 220 km/h, well below its peak. The JTWC recorded one person drowned and one missing on Luzon's northeastern tip and thousands of damaged houses. It killed 14 people, destroyed 1,779 homes and caused US$9.6 million of damage in 1997 dollars. Joan passed between Saipan and Anatahan on 18 October with gusts to 85 kt on Saipan.

Typhoon Keith, the tenth super typhoon, jumped from 105 to 155 kt in 24 hours and reached its peak on 1 November. Its small eye and narrow eyewall threaded the channel between Saipan and Rota, and no island took the full force of the storm. Keith held super typhoon strength for 3.5 days before recurving.

Linda in Vietnam, Paka on Guam

Typhoon Linda formed east of the Philippines at the end of October, crossed into the South China Sea and struck Ca Mau province in southern Vietnam on 2 November. It reached typhoon strength in the Gulf of Thailand, crossed the Malay Peninsula and briefly regained typhoon strength in the Bay of Bengal, the first storm to make that low-latitude crossing since 1992. The JTWC cited newspaper reports of at least 330 dead and about 2,250 missing in Vietnam and Thailand as of 8 November, many of them fishermen and sailors caught at sea. Linda killed 3,070 people in Vietnam, most of them drowned at sea.

Typhoon Mort reached 65 kt in the Philippine Sea and came ashore on Luzon as a depression on 16 November, which ends the archive's tropical-stage record for the year. December brought no new storm in the basin. Paka, another central Pacific storm, crossed the date line on 7 December and passed over Guam on 16 December as a super typhoon, with reliable gusts up to 149 kt. The JTWC put Guam's losses at about US$600 million in 1997 dollars; about 1,500 buildings were destroyed, and the name was retired.