Severe Tropical Cyclone Grant

23 - 29 December 2011


Tropical Cyclone (TC) Grant crossed the Northern Territory coast as a category 2 system and caused heavy rain across the top end.

A tropical low formed within an active monsoon trough just north of the Northern Territory coast during 23 December. Overnight on 24 December, the low rapidly intensified and reached tropical cyclone intensity on Christmas morning, 25 December. The cyclone reached category 2 intensity as it tracked to the south passing to the east of Croker Island and peaking at 60 knots (kn) (111 kilometres per hour (km/h)) as it made landfall on the Cobourg Peninsula coast in the evening.

During the early morning of 26 December, TC Grant continued moving to the south on 26 December weakening below cyclone intensity in the afternoon near Jabiru.

TC Grant caused torrential rainfall over parts of the Cobourg Peninsula and the adjacent north coast of the Arnhem District. Many trees were brought down in the community of Minjilang on Croker Island and the surrounding outstations and power supply was interrupted. Coastal erosion and minor flooding of low-lying coastal areas was reported between the Cobourg Peninsula and Nhulunbuy due to a combination of spring tides, larger than usual swell and strong onshore monsoonal winds. The Automatic Weather Station at McCluer Island reported a maximum wind gust of 68 kn (126 km/h) at 0907 Universal Time Coordinated (UTC) (6:37 pm Australian Central Standard Time (ACST) (ACST=UTC+9.5 hours)) on 25 December as TC Grant passed to the west.

Overnight on the 26 December and during the early morning of the 27 December heavy rainfall occurred over the Edith, Cullen and Fergusson River Catchments, including 385 millimetres (mm) at Edith River Falls in the 24 hours to 9 am ACST 27 December. A rapid river rise damaged a railway bridge and caused a train to derail while crossing over it. Significant damage was also made to the Stuart Highway rendering it impassable for two to three days.

Ex-TC Grant moved steadily to the east over the Top End of the Northern Territory during 27 December and moved into the Gulf of Carpentaria on 28 December, weakening near the Queensland side of the gulf on 29 December. Tides were abnormally high in the Gulf of Carpentaria during this time.

For more information see the TC Grant Report (pdf).

Track and Intensity

Best Track of Tropical Cyclone Grant