Summary
Severe Tropical Cyclone Zelia was a small but very intense cyclone, notable for its rapid development to category 5 off the Pilbara coast of Western Australia. Zelia crossed the coast at category 4 strength near the De Grey River mouth northeast of Port Hedland on 14 February.
A tropical low (18U) was first tracked on 8 February just off the north Kimberley coast. The low remained weak and moved west-southwest for several days, before turning more southwest late on 10 February. On 11 February the environment became more conducive to development, and the winds around 18U strengthened to gale force. It strengthened into Tropical Cyclone Zelia at 1800 UTC (2 am AWST 12 February, AWST=UTC+8) 11 February, about 280 kilometres west of Broome.
On the evening of 12 February, Zelia slowed down and became near stationary about 130 kilometres north-northwest of Port Hedland. The ocean in this area was experiencing a marine heatwave and sea surface temperatures were extremely high (31-32°C). Zelia underwent a period of extremely rapid intensification, strengthening to category 5 at 1500 UTC 12 February. Zelia spent another day moving slowly and erratically at category 5 strength, reaching its peak of 115 kn at 1200 UTC 13 February. Then on the morning of 14 February, it turned southeast and moved towards the coast.
As the cyclone approached land it weakened slightly but still crossed as a high-end category 4 cyclone near the De Grey River mouth at 0400 UTC 14 February. It retained severe tropical cyclone strength through the afternoon as it moved inland, with a discernible eye persisting on radar. During the evening, however, it weakened very rapidly. It was downgraded to a tropical low at 1800 UTC 14 February near Marble Bar.
The very destructive core of the cyclone did not directly impact any towns. Port Hedland experienced damaging winds in the periphery of the cyclone for about seven hours on 14 February as Zelia approached landfall (maximum recorded gust 65 kn (120 km/h)). Marble Bar experienced gusts up to 59 kn (109 km/h) during the evening as the weakening cyclone tracked 15 kilometres to the west of the town centre.
Rainfall and flooding caused significant impacts and the event produced record 3-day rainfall totals at De Grey and Pardoo stations, each receiving over 500mm. Numerous other sites in the Pilbara received over 200mm. Record flooding occurred on the De Grey River. The most notable record was observed at Marble Bar where the river peaked at 10.23 m on the morning of 15 February, around 2 metres above the previous record of 8.3 m from 1998. The Great Northern Highway was cut at Coolenar Pool for an extended period, isolating Pilbara and Kimberley communities. Evacuations from remote communities Warralong and Gooda Binya were conducted during the rising flood.
The closures of ports at Port Hedland (three days), Cape Lambert and Dampier disrupted shipping and combined with disruptions to offshore oil and gas operations resulted in significant economic costs to industry.
For more information see the TC Zelia Report (doc).
Track and Intensity
