Some Waianae Valley residents evacuated Thursday night because of a third brush fire in the valley this week.

The fire spread along a steep mountain flank and burned about 150 acres by 8 p.m., but did not damage any structures, said Honolulu fire Capt. Terry Seelig.

He said firefighters were able to stop the wildfire from reaching about eight houses, orchid farms, or agricultural lots near Piliuka Place toward the back of Waianae Valley. 

Police warned the residents that they should prepare to evacuate and some of them did, he said.

The Red Cross opened a shelter Thursday night at Waianae District Park, but closed the shelter at 9 p.m. Thursday. 

Seelig said the fire broke out about 3 p.m. A fire helicopter made water drops at the top flank of the fire to keep it from reaching the ridgeline and continuing over into Makaha Valley.

Federal firefighters, who were working on extinguishing the larger Lualualei fire that started on Monday, were asked to help and diverted a Marines CH-53 helicopter, two fire vehicles, and four firefighters to the Piliuka fire, said Agnes Tauyan, Navy spokeswoman.

Seelig said Thursday’s fire was not related to the Lualualei fire or a three-acre brush fire that burned near Piliuka on Wednesday. The cause was undetermined.