LES

History

Tropical Cyclone Les began as an area of low pressure that formed over the Gulf of Carpentaria on 19 January 1998. The system was initially slow to organise, drifting first towards the southwest and then turning back towards the east, and late on 21 January it passed over Queensland's Cape York Peninsula. Once over the peninsula the low began to intensify, aided by a surge of moisture associated with a northwest monsoon flow and a tightening pressure gradient created by a high pressure system sitting over the Great Australian Bight. After the system tracked back westwards into the Gulf of Carpentaria, the Bureau of Meteorology issued its first warning on 23 January. Les reached Category 2 intensity on the Australian scale before moving into the Northern Territory.

Although only a moderate cyclone in terms of wind strength, Les proved devastating because of its rainfall. More than 380 mm fell across the affected region within 48 hours, and drainage of the resulting floodwater was hampered by king high tides in the Timor Sea, which pushed water upstream in the lower reaches of the river systems. The worst flooding struck Katherine, where waters began rising on 24 January and eventually covered much of the town to depths of around 2 m. Residents were moved to cyclone shelters and some were rescued from rooftops. By Australia Day the highways north and south of Katherine were cut, and RAAF personnel from Base Tindal joined police and emergency services in sandbagging key infrastructure. A state of emergency was declared on 27 January, with the Katherine River peaking at 20.4 m at the railway bridge — surpassing the previous record of 19.3 m set in 1957. Around 5,000 people were evacuated and some 1,200 homes and 500 businesses were inundated, including Katherine District Hospital. A further 392 people were evacuated from the Daly River area, where the flood crested at 16.8 m on 3 February.

Three people died, damage exceeded A$100 million, road access to Darwin was severed for five days, and failed sewerage systems triggered a gastroenteritis outbreak.

Sources: Bureau of Meteorology report Wikipedia