Portland General Electric says it expects to restore power by Friday night to 90% of its customers who remain in the dark—but the final 10% could be without electricity through the weekend.

As of 5 pm Wednesday, about 142,000 households remained without power statewide after an ice storm toppled trees and severed power lines across the Willamette Valley on Valentine's Day weekend. The vast majority of ongoing outages—137,000 households—are served by PGE, and the remainder are served by Pacific Power.

Pacific Power says it will restore service to all its customers by Friday. PGE is telling its customers to expect the possibility of a longer wait. Combined, that means 93% of customers still without power should see fixes before Saturday.

"We're still out there doing assessments and taking stock of specific locations," says Steve Corson, a spokesman for PGE.

Corson says the outages are most heavily concentrated in Clackamas County (with 654 reported outages) and Marion County (468), although Multnomah County has plenty (395).

"The way the storm unrolled, it was really heavily tilted toward Clackamas and Marion counties," Corson says. "Multnomah County not so much, until the third wave of the storm pulled through Monday night. Then it caught up with the others."

Some 330,000 Oregonians awoke Monday morning without electric power, the largest outage in state history and one that has killed at least four people, who died in Clackamas County from carbon monoxide poisoning as they tried to heat their homes.

The Clackamas County Sheriff's Office released further information on those deaths this afternoon. Three people died trying to heat their RVs from propane tanks, the sheriff's office said, and another person was using charcoal briquets to heat a small space.

Corson says PGE has 3,000 people working to restore service. The utility has repaired 29 transmission lines—the main power lines conveying electricity to substations—but has 11 transmission lines still down.

"Even though we have 137,000 customers out, we have restored power to more than 490,000 customers," Corson says. "The unfortunate reality is that that one customer can be on both sides of that ledger, because we've had multiple outages. You can have your power restored, and then a tree limb comes down."