The cause of last night's island-wide blackout appears to be related to three transmission lines eminating from the Kahe Power Plant in Waianae and one from the Waiau Power Plant in Pearl City, which all went down within 20 minutes of each other, Hawaiian Electric Co. said today.

The loss of the four transmission lines caused a chain reaction that eventually shut down all of the six generators at the Kahe Power Plant and two generators at Waiau, HECO spokesman Darren Pai said at a press conference.

HECO is still investigating the cause of the outage but Pai said several witnesses reported lightning strikes near the transmission lines.

As of 2 p.m. today, 260,000 of HECO's 293,000 customers had power restored — or 89 percent.

Pockets of neighborhoods in Kaneohe and in between Hawaii Kai and Aina Hina.