About 100,000 businesses and homes in the Portland area were without power Wednesday as outages caused by the weekend’s massive winter storm stretched into a fifth day.

Portland General Electric, which serves the majority of customers in the metro area, reported nearly 70,000 customers in Clackamas County were without power as of 6 a.m. The lights were still out for another 27,000 in Multnomah County and nearly 3,000 customers in Washington County were suffering from outages.

The outages have had deadly consequences. At least four people died over the weekend in Clackamas County from carbon monoxide poisoning, though officials did not say exactly where or when the deaths occurred. Another six people were sickened by the odorless gas in Gladstone on Tuesday, two of them suffering critical injuries.

Rob Hendrickson, medical director of the Oregon Poison Center, said the center took 19 calls about carbon monoxide poisoning over the weekend, as opposed to one they receive on a typical weekend.

“It is extremely important not to use outdoor grills or generators inside your home,” Hendrickson said in a statement. “These appliances should be used outdoors, well away from windows, doors and ventilation systems.”

The outages continued to hamper efforts to hold classes virtually as well, with some customers having power, but no internet service. Portland Public Schools, the state’s largest district, was moving forward with online learning, but some other districts had canceled all classes and activities.

While snow still remains on the ground in many places around Portland and some local road closures remained in effect, the thaw is expected to continue Wednesday with mostly clear skies and high temperatures in the 40s.

— Kale Williams; kwilliams@oregonian.com; 503-294-4048; @sfkale