Cyclone Alby
| Category 5 severe tropical cyclone (Aus scale) | |
|---|---|
| Category 4 (Saffir–Simpson scale) | |
Satellite image of Cyclone Alby on 2 April 1978
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| Formed | 27 March 1978 |
| Dissipated | 5 April 1978 |
| Highest winds |
10-minute sustained: 200 km/h (125 mph) 1-minute sustained: 215 km/h (130 mph) |
| Lowest pressure | 930 hPa (mbar); 27.46 inHg |
| Fatalities | 5 direct, 2 indirect |
| Damage | $45 million (1978 USD) |
| Areas affected | Western Australia |
| Part of the 1977–78 Australian region cyclone season | |
Severe Tropical Cyclone Alby was regarded as the most devastating tropical cyclone to impact southwestern Western Australia on record. Forming out of an area of low pressure on 27 March 1978, Alby steadily developed as it tracked southwestward, parallel to Western Australia. Between 1 and 2 April, the storm quickly intensified and attained its peak intensity as a Category 5 cyclone on the Australian cyclone intensity scale. After turning to the southeast, the storm underwent an extratropical transition as it neared Cape Leeuwin. The storm brushed the cape on 4 April, bringing hurricane-force winds, before rapidly losing its identity the following day.
In Western Australia, the combination of Alby's fast movement and hurricane-force winds caused widespread damage. Along the coast, large swells flooded low-lying areas and numerous homes lost their roofs from high winds. Further inland, bushfires were worsened by the storm as it brought little rain, generally less than 20 mm (0.79 in) along the coast. These fires burned roughly 114,000 hectares (281,700 acres) and destroyed two towns. Five fatalities are directly attributed to Alby while two more resulted from the fires. The resulting damage was extensive, with monetary losses reaching A$50 million ($45 million USD).
Severe Tropical Cyclone Alby was first identified on 27 March 1978 as a disorganized area of low pressure situated roughly 800 km (500 mi) north-northwest of Karratha. At this time, the system was characterised as a large cluster of convection converging around the low. Notable development took place over the following three days as the system drifted towards the southwest. Convection began wrapping around the storm, forming banding features. Early on March 29, the Joint Typhoon Warning Center (JTWC), classified the system as a tropical storm. Shortly thereafter, the Bureau of Meteorology in Perth classified it as a tropical cyclone, assigning it with the name Alby. Gale force winds were later confirmed on 30 March by the Martha Bakke, located 385 km (239 mi) west-northwest of the storm's centre. By then, a large ragged eye developed and Alby steadily intensified through 2 April. At the end of this strengthening, Cyclone Alby attained its peak intensity as a Category 5 on the Australian cyclone intensity scale; a barometric pressure of 930 mbar (hPa; 27.46 inHg) was measured at the time and peak winds were estimated to be 205 km/h (125 mph) based on the Dvorak technique. Additionally, the JTWC assessed the storm to have attained winds of 215 km/h (135 mph), a low-range Category 4 on the Saffir–Simpson Hurricane Scale.
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