Hawaii Kilauea volcano eruption: State of emergency declared as lava flow could hit residents recovering from Tropical Storm Iselle

The lava has so far been moving at a rate of 800 feet per day

Fluid lava streams from the Kilauea volcano in Pahoa, Hawaii. (AP Photo/U.S. Geological Survey)

Residents of rural Hawaii still reeling from Tropical Storm Iselle are now bracing themselves for lava flow that could reach their community within a week.

Lava from the Kilauea volcano is less than a mile (2km) away from Kaohe Homesteads, and the scorching liquid could hit the area in five to seven days if it continues on its current path, geologists with the Hawaiian Volcano Observatory have said.

On Thursday, they raised the alert level and Mayor Billy Kenoi declared a state of emergency in the area. The status will allow authorities to restrict access to roadways so residents of the Homesteads can leave safely if an evacuation becomes necessary.

It wasn't immediately clear how many homes could be affected.

The alert comes after Iselle flattened trees and knocked out power in the agricultural area part of the Big Island's Puna district.

Iselle brought heavy rain and violent wind when it hit land over the southeastern part of the island. In the storm's wake, residents armed with chain saws spent the next day hacking at trees blocking roads or helping neighbours patch up damaged roofs.

Since 10 July, the lava has been advancing around 800 feet (244 metres) per day, according to the scientists closely monitoring the flow.

Fluid lava streams from the Kilauea volcano in Pahoa, Hawaii. (AP) (AP Photo/U.S. Geological Survey)

The county is asking all of Puna to be on alert because it's possible the lava could change direction and threaten other communities, Mayor Kenoi said.

Experts said predicting the flow’s journey can be difficult due to subtle variations in the island’s topography, changes in lava volume and where and how lava enters or exits ground cracks.

Hawaii County Civil Defense Administrator Darryl Oliveira said the agency has not yet ordered people to be evacuated from their homes, but will do so when it becomes clear that the lava is at least five days from impacting homes.

The Kilauea volcano has been continuously erupting since 1983, but new vents — or points where lava reaches the surface — have opened periodically.

While the volcano's lava does not normally approach homes, it wiped out neighborhoods in 1990.