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Typhoon Irma (1981)
Encyclopedia
Super Typhoon Irma was the 25th named storm, fourteenth typhoon, and second super typhoon of the 1981 Pacific typhoon season
. A powerful late season typhoon, Irma reached a peak wind speed of 160 mph (260 km/h) before hitting the northern Philippines
as category 2
typhoon, causing considerable damage and 200+ casualties. Irma was the third strongest typhoon to make landfall in the Philippines since records began in 1947.
. The disturbance was moving northward and then westward as a cluster of thunderstorms. Because of the strong outflow from nearby Typhoon Hazen, the disturbance never was able to strengthen further. When Hazen moved off to the west, the tropical system was able to re-organize itself as a central circulation was defined on radar and satellite readings. On November 17, a Hurricane Hunter aircraft detected 35 mph (56 km/h) winds, which upgraded the disturbance to Tropical Depression 26W. 26W continued to move westward where it further strengthened and became Tropical Storm Irma as it bypassed Guam
to the north on November 19.
Aided by a strong subtropical ridge
building to the north, Irma gradually reached Category 1
status on November 20. Still pushed westward by the subtropical ridge, Typhoon Irma underwent rapid intensification as the pressure dropped below 925 millibars in a 12-36 hour period. The next day the hurricane hunter plane recorded a low barometric pressure of 905 millibars, upgrading Irma to super typhoon status.
Irma remained at super typhoon strength before gradually weakening as the outer edge of the storm made contact with land. Irma finally made landfall in the northern Philippines as a Category 2 typhoon. By November 24, the landfall and an oncoming frontal system had caused Irma to weaken to a tropical storm. Poorly organized, Irma recurved in the South China Sea
before being sheared apart and dissipating south of Japan
.
Officials issued a tropical storm warning for Guam when Irma formed on November 17. Fortunately the storm bypassed Guam to the north and west where the only effects from it was 35 mph (56 km/h) winds with 50 mph (81 km/h) gusts. In the Philippines, the storm caused widespread damage. The hardest hit was the island of Luzon
where 50 ft waves sank a cargo ship and heavy rains and strong winds caused $9 million dollars (1981 USD
) in damage and 200-409 fatalities. The death toll made Irma the 15th deadliest typhoon to strike the Philippines since records began in 1947. The decaying remnants of Irma then brought 4-5.9 inches (101–150 mm) of rain and winds of 40-45 mph (40–72 km/h) to Okinawa and the minor Japanese islands.
1981 Pacific typhoon season
The 1981 Pacific typhoon season has no official bounds; it ran year-round in 1981, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern...
. A powerful late season typhoon, Irma reached a peak wind speed of 160 mph (260 km/h) before hitting the northern Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
as category 2
Tropical cyclone scales
Tropical systems are officially ranked on one of several tropical cyclone scales according to their maximum sustained winds and in what oceanic basin they are located...
typhoon, causing considerable damage and 200+ casualties. Irma was the third strongest typhoon to make landfall in the Philippines since records began in 1947.
Meteorological history
An area of convection was detected on November 15 near PonapePohnpei
Not to be confused with Pompeii, the ancient city destroyed by Vesuvius in AD 79.Pohnpei "upon a stone altar " is the name of one of the four states in the Federated States of Micronesia , situated among the Senyavin Islands which are part of the larger Caroline Islands group...
. The disturbance was moving northward and then westward as a cluster of thunderstorms. Because of the strong outflow from nearby Typhoon Hazen, the disturbance never was able to strengthen further. When Hazen moved off to the west, the tropical system was able to re-organize itself as a central circulation was defined on radar and satellite readings. On November 17, a Hurricane Hunter aircraft detected 35 mph (56 km/h) winds, which upgraded the disturbance to Tropical Depression 26W. 26W continued to move westward where it further strengthened and became Tropical Storm Irma as it bypassed Guam
Guam
Guam is an organized, unincorporated territory of the United States located in the western Pacific Ocean. It is one of five U.S. territories with an established civilian government. Guam is listed as one of 16 Non-Self-Governing Territories by the Special Committee on Decolonization of the United...
to the north on November 19.
Aided by a strong subtropical ridge
Subtropical ridge
The subtropical ridge is a significant belt of high pressure situated around the latitudes of 30°N in the Northern Hemisphere and 30°S in the Southern Hemisphere. It is characterized by mostly calm winds, which acts to reduce air quality under its axis by causing fog overnight, and haze during...
building to the north, Irma gradually reached Category 1
Saffir-Simpson Hurricane Scale
The Saffir–Simpson Hurricane Scale , or the Saffir–Simpson Hurricane Wind Scale , classifies hurricanes — Western Hemisphere tropical cyclones that exceed the intensities of tropical depressions and tropical storms — into five categories distinguished by the intensities of their sustained winds...
status on November 20. Still pushed westward by the subtropical ridge, Typhoon Irma underwent rapid intensification as the pressure dropped below 925 millibars in a 12-36 hour period. The next day the hurricane hunter plane recorded a low barometric pressure of 905 millibars, upgrading Irma to super typhoon status.
Irma remained at super typhoon strength before gradually weakening as the outer edge of the storm made contact with land. Irma finally made landfall in the northern Philippines as a Category 2 typhoon. By November 24, the landfall and an oncoming frontal system had caused Irma to weaken to a tropical storm. Poorly organized, Irma recurved in the South China Sea
South China Sea
The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Singapore and Malacca Straits to the Strait of Taiwan of around...
before being sheared apart and dissipating south of Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
.
Impact
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
where 50 ft waves sank a cargo ship and heavy rains and strong winds caused $9 million dollars (1981 USD
United States dollar
The United States dollar , also referred to as the American dollar, is the official currency of the United States of America. It is divided into 100 smaller units called cents or pennies....
) in damage and 200-409 fatalities. The death toll made Irma the 15th deadliest typhoon to strike the Philippines since records began in 1947. The decaying remnants of Irma then brought 4-5.9 inches (101–150 mm) of rain and winds of 40-45 mph (40–72 km/h) to Okinawa and the minor Japanese islands.
See also
- Other storms of the same name