Category 4 severe tropical cyclone (Aus scale) | |
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Category 4 tropical cyclone (SSHWS) | |
![]() Satellite image of Cyclone Isaac near peak intensity | |
Formed | February 27, 1982 |
Dissipated | March 5, 1982 |
Highest winds | 10-minute sustained: 175 km/h (110 mph) 1-minute sustained: 240 km/h (150 mph) |
Lowest pressure | 930 hPa (mbar); 27.46 inHg |
Fatalities | 6 |
Damage | $10 million (1981 USD) |
Areas affected | Tonga |
Part of the 1981–82 South Pacific cyclone season |
Severe Tropical Cyclone Isaac in February and March 1982 was thought to be the worst tropical cyclone, to affect the South Pacific island nation of Tonga since an unnamed tropical cyclone in 1961. The system was first noted during February 27, as an area of low pressure within the South Pacific Convergence Zone to the southwest of Tokelau. Over the next couple of days the system gradually developed further and was named Isaac during March 1, after it had become a tropical cyclone.
The tropical cyclone developed 160 km/100 mi northeast of western Samoa and travelled southwest at 12 knots, moving through the Ha'apai island group and only 50 km/30 mi northwest of Tongatapu. The pressure at Tongatapu fell to 976.4 mbar (28.83 inHg). Winds of 92 knots were measured at Nuku'alofa,[1] and rainfall of 120 millimetres (4.7 in) was measured there. Isaac reached maximum intensity on March 2. The tropical cyclone was the worst storm in Tonga's history, devastating the island group.[2] The island groups of Ha'apai and Vava'u were hit worst. Six were killed,[1] while 45,000 became homeless and 95% of the livestock was killed.[3] The island of Tatafa was bisected in half by a 16 metres (52 ft) wide channel caused by Isaac's storm surge.[4]