UPDATE: Waimanu Valley Brush Fire Still Burning

***Updated at 4:45 p.m. Monday.***

The fire that broke out Sunday morning in Waimanu Valley could take several days to contain, a spokeswoman for the state Department of Land and Natural Resources said.

A forestry crew using hand tools was working to clear a containment line today, spokeswoman Deborah Ward said.

The fire is burning in organic material on the forest floor known as duff, she said.

Posted at 10:36 a.m.:

A fire department rescue helicopter was used to ferry firefighters and make water drops on a brush fire that blackened four acres in Waimanu Valley Sunday.

Responding to an 8:44 a.m. call, personnel from the Honokaa Fire Station traveling to the Waipio Valley lookoiut observed a plume of smoke coming from the west.

The fire was determined to be located in Waimanu, a remote valley which is accessible only by air, water or a rugged nine-mile-long hiking trail from Waipio Valley.

Reconnaisance from Chopper 1 showed the fire had initially burned about two acres under the forest canopy, Capt. Christian Wong of the Honokaa station said in a statement.

The trail to Waimanu was temporarily closed, and fire department personnel kept hikers out of dangerous areas while the helicopter made water drops.

With the water drops reducing the intensity of the fire, a team of firefighters was brought to the scene to begin containment efforts. Personnel from the state Division of Forestry and Wildlife were also brought in to assist.

The effort was later suspended because of darkness and was to resume today.

The trail into the valley has been reopened.

The cause of the fire is under investigation.