Troubleshooters are trying to figure out why Hawaii Kai, Kalama Valley and parts of Kuliouou were without electrical power this morning for about 45 minutes.

Darren Pai, the Hawaiian Electric Co. spokesman, said the outage began at about 6:45 a.m. He did not know how many households or businesses were without power.

The morning commute traffic backed up as drivers navigated Kalanianaole Highway without traffic lights until power was restored.

The Department of Education said that all public schools in the Hawaii Kai-Koko Head area are open this morning following the three-day Martin Luther King holiday.

Pai said another outage in Pearl City Monday night cut off power for about 900 customers beginning at 8:40 p.m. because of a problem with an underground cable.