Fire threat looms again as newly watered grasses dry

The terrible bushfires of the recent past could be eclipsed by a rising threat this summer - grassfires. Photo / Getty Images

As Australia emerges from a long, cold winter the nation is being warned to prepare for what may be a summer of devastating grass fires.

Authorities in several states have already issued alerts, concerned at huge areas of grass watered by floods and some of the heaviest rains on record, and now drying to tinder.

The warnings cover most of the inland and embrace rural towns and cities, cropland and massive tracts of cattle and sheep country.

About three-quarters of the continent is covered by grasslands, accounting for much of the 2.5 million hectares burned on average every year by wildfires.

Although not as hot as bushfires, grass fires are much faster, with winds whipping flames that generally reach five times the height of the grass and spit out cinders as far as 100m ahead of the front.

Grim predictions of a fearsome summer firmed last week at a bushfire assessment workshop in Adelaide that brought together meteorologists, fire authorities and land managers from around the country.

Their reports confirmed that very large areas of grass watered by last summer's rains - the eight months to last March were the wettest on record - now present the threat of major fires. The workshop's conclusions make sober reading in the Bushfire Co-operative Research Centre's Southern Australia Seasonal Bushfire Outlook for the states and territories below the Tropic of Capricorn.

"A thick, tall band of grass extends across much of the middle of Australia from the Indian Ocean in the west to the Pacific Ocean in southern Queensland and the Great Dividing Range in New South Wales," the outlook said.

"The grass - waist and even shoulder- high in places - has flourished because of the heavy rains that accompanied the very strong La Nina event at the beginning of 2011.

"With much of this grass now curing because of drier recent weather, the potential exists for above-normal bushfire activity across the centre of Australia during the [coming] southern fire season."

The threat is a potentially deadly flip-side to the drought that gripped much of Australia for a decade, ending last year when one of the strongest La Nina events on record dumped disastrous rainfall down the east coast.

Until the rain came, drought had kept major grass fires at bay.

But the continent is now carrying vast, fast-drying fuel loads.

The bushfire outlook warns that prolific growth has created a "continuous grassland sward" that is now curing to tinder over southern Queensland, from Wide Bay in north Queensland south to the Gold Coast, and west to the South Australian border.

Warnings of "above-normal" fire potential embrace much of southern Queensland, including the Beaudesert, Boonah, Lockyer and Brisbane Valleys, through to the Sunshine Coast and north to Wide Bay, and west to include most inland grassland areas as far as the Northern Territory and South Australian border.

In New South Wales, similar growth has covered most areas west of the Great Dividing Range, creating a potential tinderbox.

The potential for major grass fires in Victoria has been increased by the low stocking rates forced on farmers by the drought, less irrigation in the north and intensive cropping systems that have reduced the area of fallow fields.

The western and northern regions of South Australia and much of the midwest of Western Australia also face serious grass fire threats.