By James Regan
SYDNEY (Reuters) - Three days after making landfall, Cyclone Nathan continued to threaten Australian coastal communities, with 400 residents of a remote northern island on Monday ordered to evacuate after meteorologists warned the storm was intensifying.
It is the second time since late February that people living in Goulburn Island off Australia's Northern Territory have had to evacuate to escape a tropical cyclone.
"Police have the power to force people to evacuate," said regional controller Commander Bruce Porter of the Northern Territory Police. "We do not however, expect to enforce this, as residents are cooperating with the evacuation.”
Sparsely populated with little in the way of industry, the island 300 km (185 miles) northeast of Darwin is comprised largely of marshlands harboring an abundance of wildlife including crocodiles, fish, dugong, and turtles.
Nathan crossed the eastern Australia coast on Friday before weakening over land only to regain much of its punch as it crossed over the tropical waters off the Northern Territory.
Tropical cyclones typically weaken rapidly over land, where they are cut off from their primary energy source - warm water. For this reason, coastal communities are particularly vulnerable to damage from a tropical cyclone as compared to inland regions.
Meteorologists said Nathan was moving north-west at 12km (7 miles)per hour and would strengthen over open water before again making for land.
The storm is expected to reach a category 3, moving parallel to the coast before turning southwest toward land late on Monday or early Tuesday, according to Australia's Bureau of Meteorology.
Category three is classified as severe and generating wind gusts of between 165 and 224km (100-140 miles) per hour over open flat land.
In February, Cyclone Lam smashed near the same coastline, displacing about 200 people and destroying some 50 homes.
Meteorologists warn such cyclonic activity may increase the chance of El Nino weather pattern in 2015 by raising ocean surface temperatures in the coming months.
El Nino can lead to drought in Southeast Asia and Australia and heavy rains in South America, hitting production of food such as rice, wheat and sugar.
Meteorologists this month forecast that the chance of an El Nino developing this year had risen to about 50 percent.
(Reporting by James Regan; Editing by Michael Perry)