Australia storms: Cyclones hit Queensland and Northern Territory

Two major storms have slammed into Australia, knocking out power, damaging homes and forcing evacuations in coastal areas.

Tropical Cyclone Marcia hit the Queensland coast between Yeppoon and St Lawrence on Friday morning local time.

Arriving with little warning as a Category Five storm, it has now been downgraded to a Two but still threatens high tides and heavy rain.

Separately, Tropical Cyclone Lam hit a remote area of the Northern Territory.

'Terrifying experience'

In its latest update, the BOM said Marcia had weakened to a Category Two cyclone, with sustained winds of 110km/h (72mph) and gusts of up to 155km/h.

It was about about 60km west of the town of Gladstone, Queensland and 65km north-northeast of Biloela, and moving south-southeast at 18 kmh but expected to weaken below cyclone strength by Saturday morning.

"Destructive winds" battered coastal and island communities including Yeppoon in Queensland

About 870 Yeppoon homes were evacuated because of possible storm surges

Surfers off the Gold Coast made the most of the rough sea conditions

The BoM warned of abnormally high tides and said people in coastal areas should be ready evacuate if necessary.

Earlier on Friday, the storm passed through Rockhampton and Yeppoon, where Queensland Premier Annastacia Palaszczuk said people of had gone through a "terrifying experience".

"We are very, very thankful that we have avoided the worst of what could've been an absolute catastrophe if those winds had escalated and the Category Five had gone straight over Yeppoon," she told reporters in Brisbane.

Ms Palaszczuk said earlier that 33,000 residences were without power in the Livingstone/Yeppoon area and 20,000 in Rockhampton.

There were no reports of injuries, but some homes and businesses suffered significant structural damage, she tweeted.

In Yeppoon, about 870 homes were evacuated because of storm surges, according to Queensland emergency authorities.

More than 170 schools and childcare centres had been closed, and people evacuated or moved to safety on both Lady Elliot Island and Heron Island, on the Great Barrier Reef.

The mayor of Rockhampton, Margaret Strelow, told ABC Radio that Marcia was like "a real moving beast" as it appeared to head first to the west of the city and then to the east.

Further south, local media reported that 90,000 sandbags had so far been handed out across Queensland's major city, Brisbane, because of predictions of heavy rain and flooding.

Describing the cyclone as "very serious", Prime Minister Tony Abbott said: "Let's hope we can get through it without any loss of life."

Roads impassable

Cyclone Lam, which arrived as a Category Four, struck close to the tiny and remote indigenous settlements of Elcho and Goulburn Island, east of Darwin.

Some communities had been evacuated ahead of the storm, but others spent the day in emergency shelters.

These children were evacuated to Darwin along with their entire community from Goulburn Island

Regional police commander Bruce Porter said Elcho Island had no power or water, and that there had been "substantial" damage.

"Initial reports are the airstrip is still intact but covered with debris," the AFP news agency quoted him as saying.

"There are downed power lines. There are a number of trees down and many roads are impassable and we do have a number of buildings and houses that have been severely damaged."

Lam has now been downgraded to a tropical low, but Australia's Bureau of Meteorology (BoM) warned of further "squally thunderstorms" and high tides.

Satellite images of Cyclones Lam (top) and Marcia