| Category 4 super typhoon (SSHS) | |
|---|---|
| Irma near peak intensity | |
| Formed | November 17, 1981 |
| Dissipated | November 27, 1981 |
| Highest winds | 1-minute sustained: 250 km/h (155 mph) |
| Lowest pressure | 902 mbar (hPa; 26.64 inHg) |
| Fatalities | 261 total |
| Damage | $35 million (1981 USD) |
| Areas affected | Philippines, Japan |
| Part of the 1981 Pacific typhoon season | |
Super Typhoon Irma (international designation: 8126, JTWC designation: 26W, PAGASA name: Typhoon Anding), was the 25th named storm, fourteenth typhoon, and second super typhoon of the 1981 Pacific typhoon season.[1] 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.[2]
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An area of convection was detected on November 15 near Ponape. 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.[3]
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.[3][4] 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.[5][6]