Ice clings to power lines Monday in northeast Portland, causing power outages that closed schools.

At least 140,000 customers still had no power Tuesday morning as the havoc wrought by a powerful winter storm lingered around Portland. In Marion County, another 60,000 homes and businesses were without power.

The lack of power and damage from the storms may have contributed to six people suffering from possible carbon monoxide poisoning in Clackamas County, closed many school districts in the Portland metro area and led to a number of roads being closed.

Portland General Electric reported three substations were still out of commission, 21 transmission lines had been knocked out and more than 6,000 individual lines were still down as of 6 a.m. Despite the efforts of more than 2,500 utility workers trying to restore service, some of whom were brought in from out of state, there was still no estimate when power would return for many customers.

For some, Tuesday would be their fourth day without electricity.

In Gladstone, emergency crews were treating the six people suspected in the carbon monoxide poisoning Tuesday morning. Few details were immediately available, but the Clackamas County Sheriff’s Office said the poisoning may have occurred after a generator was left running in an enclosed area attached to a home on E. Fairfield Street. The condition of all of the people affected was not immediately available.

The weight of ice and snow proved too much for the roof of a Safeway store in Troutdale, and it collapsed Monday morning. Customers were inside when the collapse occurred, and one person sustained minor injuries, officials said.

A Les Schwab tire store in southeast Portland suffered a similar fate Monday evening, with the roof partially caving in while a cleaning crew was inside. Everyone was evacuated, and no injuries were reported.

While the Portland metro area returned to normal winter weather Tuesday, the effects of the storm lingered as many school districts were forced to cancel even their virtual classes due to power outages.

Eight public school districts in Oregon and southern Washington were closed Tuesday, including Portland Public Schools. Portland, Clackamas and Mt. Hood community colleges were also closed.

Travel also remained difficult Tuesday morning. The Portland Bureau of Transportation reported about 50 road closures early Tuesday. Washington and Clackamas counties also reported several road closures.