1971 Pacific typhoon season

One of the busiest years since 1945

The Joint Typhoon Warning Center named 35 tropical cyclones in 1971, ten above its average and level with 1967 for the second highest total since 1945. Twenty-four became typhoons, tying 1962 for second place behind 1964's 26, and nearly matching the combined typhoon count of 1969 and 1970. The center issued 747 warnings over 163 days, both well above its 1960 to 1970 averages.

The site's archive counts 33 tropical storms, 23 typhoons, 11 major typhoons and five Category 5 storms, with an accumulated cyclone energy of 369.9. It measures every track with US-agency one-minute winds during the tropical stage, and it treats Faye and Gloria as a single storm, as other season lists do. The JTWC tallied storms from its own warnings and listed Faye and Gloria separately. The Japan Meteorological Agency, using ten-minute winds, rated one system as a tropical storm that the JTWC kept as a depression.

The JTWC credited a strong, persistent subtropical ridge, the reverse of 1970. The ridge produced the trade-wind shear and inflow that feed young depressions. In June and July it sat unusually far north over the Ryukyus, steering storms west into the South China Sea and leaving Okinawa in drought. The upper-level Mid-Pacific trough started at least a quarter of the year's typhoons, including Dinah, Mary, Shirley, Wendy, Trix and Bess.

A spring outbreak led by Wanda and Amy

Tropical Storm Sarah formed near Palau in early January, and Typhoon Vera became the first typhoon in mid-April. Seven tropical cyclones then formed in April and May, against a climatological two, and on 3 and 4 May Wanda, Amy and Babe were all active at once. The JTWC called it the greatest spring outbreak on record.

Typhoon Wanda crossed the central Philippines near Leyte Gulf in late April as a tropical storm and later became a typhoon off South Vietnam. The JTWC reported 56 dead and 39 missing in the Philippines, with property damage near $700,000, and more than 23 deaths in Quang Ngai province. US forces grounded most aircraft in the north of the country while the storm passed.

Typhoon Amy peaked on 2 May at 150 kt and 890 hPa in the archive, with an eye about 10 nautical miles across; it was the most intense May typhoon on record. It never crossed land, but its winds reached the Truk district of the Caroline Islands. The JTWC reported 80 percent damage there, more than 2,250 homes demolished, one death and $4.5 million in property damage, with about $1 million more in losses to crops, boats and businesses. Namonuito Atoll was hit hardest.

A record July

July produced eight tropical storms, and five of them became typhoons, beating the previous July high set in 1967. The JTWC put the figure in context: the Atlantic averaged about eight named storms in an entire year. Between mid-June and mid-July, six tropical storms crossed the Philippines into the South China Sea, a run the center called unparalleled for early summer. Typhoon Harriet crossed Leyte Gulf and later struck near the border of North and South Vietnam, where the JTWC reported four people killed and 14 missing, plus one death in the Philippines.

Typhoon Lucy peaked at 130 kt and was the strongest typhoon to affect the Philippines that year; its southwest monsoon flow drove floods and landslides in north-central Luzon, with 379.5 mm of rain in 24 hours at Baguio. Typhoon Nadine reached 150 kt and 900 hPa on 24 July, then struck eastern Taiwan on 25 July after weakening from that peak. The JTWC recorded 28 killed and 25 missing on Taiwan, where floods caused heavy damage. Lucy, Nadine and later Wendy were the year's largest storms, each with gales reaching 300 nautical miles or more from the center.

Rose in Hong Kong and floods across Japan

Typhoon Rose was a compact storm that crossed northern Luzon north of Palanan Point on 13 August and deepened again over the South China Sea. The archive peaks it at 120 kt on 16 August, and the JTWC estimated a similar peak shortly before the eye reached Lantau Island off Hong Kong after midnight on the 16th. The Royal Observatory recorded a gust of 121 kt and 11.34 inches of rain in 24 hours, its highest calendar-day total for August. The JTWC counted 130 deaths and more than 5,600 people left homeless, with 26 ocean-going ships aground and two sunk. The Macao ferry Fatshan capsized with the loss of 88 crew.

Japan took three rain-heavy typhoons in about five weeks. Typhoon Olive drove through western Kyushu on 5 August; up to 59.8 inches fell in the mountains of Miyazaki prefecture, and the JTWC reported 69 killed and 209 injured. Typhoon Trix crossed southern Kyushu at the end of the month with up to 43 inches of rain; the JTWC listed 44 deaths and $50.6 million in crop damage in US dollars of the time. In early September Typhoon Virginia moved along the Honshu coast, and landslides in Chiba prefecture killed 56 people.

Typhoon Bess peaked at 140 kt on 20 September, then weakened before passing over Yonaguni and moving inland near Ilan on Taiwan on 22 September; the eye crossed Taipei and Keelung recorded a gust of 130 kt. The JTWC reported two deaths in the southern Ryukyus and 30 deaths with 6 missing on Taiwan, the second typhoon to strike the island that month after Agnes. Typhoon Wendy also peaked at 140 kt, well east of the Marianas, and stayed over water.

Hester at Chu Lai and Irma's record deepening

Typhoon Hester crossed Mindanao and the Visayas as a tropical storm in October, strengthened over the South China Sea and came ashore in South Vietnam on 23 October. At Chu Lai the pressure fell to 971 mb and winds reached an estimated 70 kt with gusts to 90 kt. Three quarters of the base's structures were damaged, 38 helicopters were destroyed, and three Americans died from flying debris. The JTWC judged Hester probably the most destructive storm of the war for US military property. Newspaper reports cited by the JTWC gave about 85 Vietnamese deaths and more than 200,000 left homeless.

Typhoon Irma formed south of Guam in November and deepened at about 4 mb an hour over 24 hours on 10 and 11 November. A dropsonde found 884 mb, the lowest pressure measured in over a decade. The archive records Irma's peak at 155 kt and 885 hPa late on 11 November, the season's strongest storm. Irma held the record for the fastest 24-hour deepening until Typhoon Forrest in 1983. Irma stayed at sea and curved northeast south of Japan; it caused only minor damage on western Pacific islands and disrupted shipping. Tropical Storm Judy followed, and the archive's last tropical-stage observation falls on 28 December.