Cyclone Althea

Cyclone Althea

Severe Tropical Cyclone Althea was a powerful tropical cyclone that devastated parts of North Queensland just before Christmas 1971. At 09:00 AEST on Christmas Eve, Al thea struck the coast of Queensland near Rollingstone, about 50 km north of Townsville. Three people were killed and damage totaled USD 120 million. The storm prompted Queensland to develop its first statewide building codes, requiring new homes to be cyclone-resistant.

About Cyclone Althea in brief

Summary Cyclone AltheaSevere Tropical Cyclone Althea was a powerful tropical cyclone that devastated parts of North Queensland just before Christmas 1971. After forming near the Solomon Islands on 19 December and heading southwest across the Coral Sea, the storm reached its peak intensity with 10-minute average maximum sustained winds of 130 kmh – Category 3 on the Australian cyclone scale. At 09: 00 AEST on Christmas Eve, Al thea struck the coast of Queensland near Rollingstone, about 50 km north of Townsville. Three people were killed and damage totaled USD 120 million. The storm prompted Queensland to develop its first statewide building codes, requiring new homes to be cyclone-resistant. The cyclone produced copious rainfall over central and western Queensland as it turned toward the southeast, and on 26 December the cyclone emerged over open waters. After briefly re-intensifying, the system dissipated on 29 December and left a trail of destruction in its wake. It is one of the strongest storms ever to affect the Townsville area, and was the fourth system and second severe tropicalcyclone of the 1971–72 Australian region cyclone season. It was also the second most powerful cyclone to make landfall in Australia, with the previous storm being a Category 2 storm in 1966. The damage was so extensive that Townsville was the first community to adopt the enhanced construction standards. It also triggered extensive river flooding in interior Queensland. Most major roads in western portions of the state were cut off by floodwaters, and hundreds of families had to leave their homes for higher ground.

In Townsville, thousands of homes were damaged and many were destroyed. The most widespread damage was to roofs, which were often poorly or not at all secured. It left nearby Magnetic Island in a state of ruin; almost all of the buildings on the island were damaged to some degree. A significant 3. 66 m storm surge battered the mainland, while high waves destroyed roads and seawalls. The strongest winds were found under the outer ring, which shrank from 55 to 39 km between 21: 00 and 23: 00 UTC between 21 December to become the dominant eyewall. While the system was moving ashore, land-based radar identified an ongoing eyewalls – rings of intense thunderstorms surrounding the centre, with two distinct concentric, concentric concentric rings – as the inner ring dissipated. The landfall point placed Townsville and Magnetic Island’s powerful winds well to the south of the centre’s gale-force winds. The system continued to organise until landfall, which occurred at 23:00 UTC on 23 December – 09:00 AEST – near Rolling stone, about50 km north ofTownsville. Early the next day, it tracked just south of an automated weather station on Flinders Reef. Late on 22 December, the eye remained obscured to satellite imagery by a canopy of cirrus clouds while thecyclone passed north of Lihou Reef. It then dissipated over open water the following day.