MARCIA

History

Tropical Cyclone Marcia was the first named system of the 1974–75 Australian region season, and an unusually early one, forming while the monsoon trough over the eastern Indian Ocean was still developing. The system began as a weak low on 17 October 1974 and organised steadily over warm open water, with the Perth Tropical Cyclone Warning Centre assigning the name Marcia on 18 October. On that same day the merchant vessel *Alkuwait* ran into the storm and reported winds close to hurricane force, although satellite imagery at the time did not appear to support an intensity that high.

Marcia tracked generally west-southwestward, remaining well offshore from the Western Australian coast and passing at a considerable distance from the North West Cape. It reached its greatest strength on 20 October. Intensity estimates for the system vary: one assessment rates Marcia as a Category 3 severe tropical cyclone with a central pressure near 965 hPa and ten-minute mean winds of roughly 130–140 km/h, while a lower estimate places peak winds near 85 km/h with a minimum pressure of 989 hPa.

On 21 October the cyclone's outer rainbands spread unsettled weather across the Cocos (Keeling) Islands, with the centre lying roughly 320 km west-southwest of the group. The following day Marcia slowed and turned westward as the steering pattern broke down under an approaching upper trough. Moving over cooler water and into stronger wind shear, the system weakened below cyclone intensity on 24 October and dissipated the next day, with its remnants drifting across 90°E into the South-West Indian Ocean.

Marcia never made landfall. No gales reached the Western Australian mainland and no casualties, injuries or structural damage were reported, though marine warnings were issued for North West Shelf shipping lanes as a precaution.

Sources: Bureau of Meteorology report Wikipedia