Cyclone off Australia threatens iron ore, gas output Storm is...

• Cyclone off Australia threatens iron ore, gas output
• Storm is intensifying
• Ports used by BHP, Fortescue, BHP clearing

(Adds port operators, details)

A tropical low in the Indian Ocean off Australia was forecast on Friday to intensify to cyclone strength within 24 hours, disrupting shipping from the world's biggest iron ore export terminals and threatening offshore production of liquefied natural gas (LNG).

The Pilbara Ports Authority said in a statement it had already cleared vessels from outer anchorages at Port Hedland, and vessels within the inner harbour would depart by 0500 GMT.

Port Hedland is used by major miners BHP Billiton (BHP) and Fortescue Metals Group (FMG) for shipping all their ore, and last month accounted for 41.2 million tonnes of exports, mostly bound for China.

The nearby port of Dampier, used by Rio Tinto (RIO) , Australia's biggest supplier of the steelmaking raw material, as well as the port of Asburton, were expected to be cleared of vessels within four or five hours, according to the authority.

The miners were not immediately available for comment. At 0230 GMT a tropical low was located 260 kilometres (160 miles) north-northeast of Port Hedland and was likely to reach category 2 cyclone intensity - at the lower end of the 1-5 intensity scale - late on Friday or Saturday, according to Australia's Bureau of meteorology.

The next forecast update is scheduled for 0400 GMT. Offshore, Woodside Petroleum (WPL), Australia's biggest independent oil and gas company, said it was "taking the necessary precautions to safeguard our people and assets".

Its operations in the region include the Pluto and North West Shelf oil and LNG fields.

While category 1 or 2 cyclones are at the lower end of the scale, they still pack enough punch to cause damage and delay port and mining operations.

On Jan. 16, 2016, a category 2 cyclone slammed the west Australian coast and was later blamed by BHP for lower-than-expected iron ore production.