A massive brushfire that has scorched thousands of acres upslope of Ma'alaea since Friday was about half contained as of yesterday afternoon.

About 3,900 acres had been burned by yesterday afternoon, said county spokeswoman Ellen Pellisero. Four helicopters — including two military helicopters — and dozens of firefighters continued to battle the blaze that began early Friday morning.

The fire began north of Ma'alaea Harbor and winds upward of 30 mph fanned the flames, forcing the closure of Honoapi'ilani Highway late Friday. Traffic is no longer affected by the blaze, said Pellisero.

The cause of the fire is still under investigation.

Flames were threatening four Maui Electric Co. transmission lines Saturday evening, but they are now in the clear, said Ron Vicens, MECO dispatch supervisor.

The lines were monitored overnight and did not carry a full electric load, as a precaution, he said. The lines were fully restored yesterday morning after MECO inspectors deemed that there was no immediate threat to the lines, he said.

Electric service was never interrupted to west Maui residents, said Pellisero.

A second small fire erupted just after 2:20 p.m. yesterday in the Makawao/Pukalani area, said Pellisero. Two helicopters were dispatched to the fire and it was extinguished by 4 p.m. yesterday.

Reach Loren Moreno at lmoreno@honoluluadvertiser.com.