Milder conditions are allowing firefighters to back-burn in two areas.

St Marys residents prepare for worst

St Marys residents are bracing for the worst as fire crews work around the clock with stretched resources to contain a bushfire on Tasmania's east coast.

A packed community meeting on Wednesday night was told to put their fire plans into action ahead of a predicted 25km/h to 35km/h north-easterly wind overnight.

Crews have spent the day putting fire breaks around communities under the most threat, but residents have been warned that resources cannot be allocated to every home.

"The fire will continue to grow," Tasmania Fire Service officer Chris Tomes said.

"We're concentrating our resources where they are most needed.

"We cannot park a fire truck outside every home. We would like to do that but it's not a reality."

The fire has now burnt some 12,000 hectares since Sunday night.

Three helicopters, eight bulldozers, 40 fire trucks and 120 personnel are working around the clock to prevent the loss of more property following Monday night's devastating firestorm at nearby Scamander which gutted 13 homes and other buildings.

Crews have spent the day installing fire breaks and backburning around communities including Four Mile Creek, Gray and Irishtown, but inaccessible terrain and wind changes have hampered some control efforts.

Prime Minister John Howard, in Tasmania to inspect the damage already inflicted on various communities in the state, said the ongoing drought throughout Australia had placed the country at extreme risk of bushfires.

"It is going to be a very, very difficult summer," he said at the burnt out Winifred Curtis Reserve in Scamander.

"It's going to be a menacing summer as far as bushfires are concerned."

Mr Howard said the fact there had been no loss of life or serious injuries in Tasmania or Victoria where fires also rage, was an "extraordinary tribute" to fire crews.

His two-and-a-half hour visit to Tasmania also included a stop at the St Helens evacuation centre, where he spoke with victims of the disaster.

Conditions are expected to worsen on Thursday, with wind gusts of up to 90km/h to 100km/h in mid-morning before a north-westerly change in the afternoon, which could push the blaze back towards Scamander.

"Our control options are limited and it's going to be some considerable time before the fire is contained," Mr Tomes said.

Mr Tomes reassured residents the Scamander firestorm was "an extreme event" which he hoped would not be repeated.

But he said no one could be certain what the fire would do next.

"Fires by their very nature are unpredictable. This is not an exact science," he said.

"It's all in the hands of somebody upstairs"

Road closures and communication outages have increased the challenges for firefighters, who are covering an 80km perimeter.

St Marys residents Paul and Genevieve Aulich have spent the past two days preparing their home for the fire.

"We really didn't think it was such a big issue until we saw the prediction of what could happen tomorrow," Ms Aulich said.

"It's starting to sink in quite well now."

Ms Aulich said she planned to defend her home but if it came too near, she and her three young children would evacuate.

"If we see it come over the hill we're gone," she said.

Break O'Day mayor Robert Legge told the meeting it was "a miracle" no one had been killed so far in the fire.

Mr Legge said smoke at Scamander on Monday night rose more than 3,000 metres into the air and "3,000 feet up you'd think the air was on fire".

"How the hell the firefighters withstood it I'm yet to know," he said.

More dead fish found in Va. river

ROANOKE, Va. - Scientists baffled by massive springtime fish kills on the Shenandoah River over several years now have additional confusing information: several hundred dead fish in December.

An environmentalist counted at least 300 dead northern hogsuckers on a 10-mile stretch of the main branch of the Shenandoah in Clarke and Warren counties last week, said Don Kain, a state Department of Environmental Quality biologist. An accurate count was impossible because many had sunk the bottom, DEQ spokesman Bill Hayden said.

About a dozen dead fish have been found this week, but they were of different species and in different parts of the river. Most of them were sunfish except for one smallmouth bass, Kain said. Half were found on the North Fork of the Shenandoah and half on the South Fork.

"That's been the toughest thing about this fish kill," Kain said. "There really aren't any concerted patterns."

None of the fish killed recently bore the cigar-burnlike lesions that afflicted fish in previous kills.

Other kills on the river prized by anglers have been in the spring, but the species have varied. Last spring, northern hogsuckers died on the mainstem Shenandoah in Clarke County, and a number of smallmouth bass and sunfish bearing lesions died on the North Fork.

Last year, 80 percent of the smallmouth bass and redbreast sunfish in the South Fork developed lesions and died. The kill was similar to one in 2004 on the North Fork of the Shenandoah.

Scientists have been unable to determine the cause of the fish kills, and the state's Shenandoah River Fish Kill Task Force that was formed to investigate will look into the recent kills.

Kain, task force co-chairman, said he'll be out on the river Wednesday looking for fish samples that scientists can study. A fish still must be alive and in distress or freshly dead in order to be useful to scientists, and the fish found over the past two weeks had been dead for a longer period.

Fish that died in previous kills showed signs of stress, and some males had female characteristics, a condition called "intersex."

Development caused the Shenandoah River to make American Rivers' 10 most endangered waterways this year for the first time.