East Coast Low (2001-07-04)

A severe low pressure system brought heavy seas onto the Queensland and New South Wales coastlines. The low originally formed to the south of Noumea, New Caledonia, equatorward of a large blocking high pressure system over New Zealand as an upper-level trough crossed the Tasman Sea.

After conducting an analysis at UK around the time of peak intensity (1200 UTC 4 July 2001) showed a cyclonic circulation up to 500 hPa and strongest in the 850 to 700 hPa layer. Above 400 hPa the system was an open trough. Scatterometer winds from satellite data at 0615 UTC 4 July 2001, revealed a low with gales almost completely surrounding it and with a huge area of gale to storm-force winds on the poleward side.

The low tracked to the east of Norfolk Island where the lowest MSLP of 990.3 hPa occurred at 1500 UTC on the 4 July 2001. At Norfolk the maximum 10-min mean wind recorded was 100/43 knots, gusting to 63 knots and occurred at 0230 UTC. 4 July 2001 and the mean sea level pressure at that time was 1001.3 hPa.

Balloon flight wind calculations from Norfolk indicated winds to hurricane force a short distance above the surface. Heavy swells affected the Australian coastline. The most exposed wave rider buoy (just east of Brisbane) recorded a peak wave height of 7.9 metres. The peak wave period was 15.9 seconds--a long period swell. The long period swells produce a larger breaking wave height than shorter period swells do.

The 11-metre cruiser "Just Cruising" was found wrecked on Spitfire Bank near the entrance to Moreton Bay and just southwest of Cape Moreton. The boat had been flipped over by the large breakers on 6 July 2001 and the crew of four were never found.

A yacht was wrecked by large waves on a sandbar near Fraser Island and the lone yachtsman was never found. Also, a woman was reported missing after being swept off her dinghy on the 7th July near Jumpinpin Bar (which separates North and South Stradbroke Islands) halfway between Brisbane and the Gold Coast. Farther east, a French yachtsman was found drowned near his stricken yacht in the Norfolk Island area.

This event is classified as an East Coast Low.

More about East Coast Lows
Harden Up
Bureau of Meteorology website
The Centre for Australian Weather and Climate Research report