The St. Louis-based utility Ameren Corp. said it would be several more days before power is fully restored.

"We've had some ice storms before. This one puts them to shame," said Ron Zdellar, vice president of energy for AmerenUE, who has worked for the company for 35 years.

About 260,000 Ameren customers in Missouri and Illinois were still without electricity Monday.

The storm also caused widespread power outages elsewhere as it blew snow and ice from Texas to Michigan last week and battered parts of the Northeast with thunderstorms and high wind.

The number of deaths blamed on the storm rose Monday to at least 23, with three more deaths reported in Missouri and one more in Illinois. The causes included weather-related traffic accidents, fires, carbon monoxide poisoning and exposure, officials said.

By late Sunday night, 22,000 Hydro-Quebec customers were still without power, compared with a peak of 276,000 people on Friday night and 53,000 at dawn Sunday.

Sunday's milder weather and low winds helped Hydro-Quebec crews make continued progress in restoring power. The utility said it expects to have its full power grid operating by noon today.

The worst effects of Friday's storm were felt just east of Ottawa, along the Ottawa River, and the Laurentian region north of Montreal.

Powerful winds fuelled a wildfire north of Los Angeles, hampering the efforts of crews trying to protect thousands of homes after flames had already gutted five residences.