Summary
Severe Tropical Cyclone (STC) Heidi was a very small system that rapidly developed and passed 15 kilometres (km) to the east of Port Hedland. Heidi's destructive core passed to the east of Port Hedland, and so a Category 2 impact was experienced at the town. The post analysis best track is shown in Figure 1.
On 9 January 2012 a tropical low formed south of Indonesia, around 290 kilometres southwest of Sawu. The low formed in a supressed phase of the Madden-Julien Oscillation, with a high amplitude Equatorial Rosby Wave aiding development. Initial movement was reasonably fast towards the south, with the system taking a more southwest motion and slowing down as it intensified and approached the coast. Category 1 intensity was reached at 1200 UTC (2000 Australian Western Standard Time (AWST) as AWST = UTC + 8 hours) on 10 January. Due to the system's small size, Heidi maintained rapid intensification throughout its life. Peak intensity is estimated to be 80 knots (150 km/h, 10-minute mean wind, 1 knot=1.852 km/hr) as Severe Tropical Cyclone Heidi reached the coast.
The crossing location was 15 km to the east of Port Hedland early in the morning on 12 January (between 2000 and 2100 UTC on 11 January). Port Hedland experienced storm force winds with 53 kn (99 km/h) recorded at the aerodrome (10 metre elevation), 57 kn (106 km/h) recorded at the Port Authority tower (at around 30 m elevation) and 54 kn (100 km/h) recorded at Beacon 15 located 20 km offshore (20 m elevation). A map of these observation locations is given in Figure 7.
Heavy rainfall occurred across the Pilbara and west Kimberley. Pardoo Station recorded 168.5 millimetres (mm) in 24 hours and Port Hedland Aerodrome recorded 108.4 mm. The Fire and Emergency Services (FESA) reported that Heidi uprooted trees across properties and roadways with minor flooding on roads and large scale power outages in South Hedland and Wedgefield. The majority of damage was caused by very strong winds and heavy rainfall.
For more information see the TC Heidi Report (pdf).
Track and Intensity NT
