Snow and freezing rain fall on South Dakota and Nebraska, posing perilous travel conditions on Christmas Day. Heavy snow is also expected in parts of Minnesota.

Freezing rain and thunderstorms pummeled parts of Ontario and Quebec on Wednesday, knocking out power for about 800,000 people, officials reported.

A winter weather system brought colder temperatures and precipitation not often seen in the region. Authorities urged drivers to stay off the roads, which forecasters said are slick and snow-packed.