One person has died following a pileup involving dozens of vehicles during a winter storm on Sunday that also left thousands without power across southern Ontario. Between 30 and 40 passenger vehicles and big-rig trucks were involved in the pileup in Kingston, Ont., on Sunday afternoon, provincial police said.

Fifteen to 20 people involved in the crash were taken to hospital, most injuries that were not considered life-threatening, a spokeswoman for Kingston General Hospital added.

Police said one person died at the scene of the crash.

It was a rough day on Ontario highways, with provincial police reporting approximately 400 crashes in the Greater Toronto Area since the snow started falling on Sunday.

Another crash killed a 24-year-old woman in the Niagara region when her Jeep collided with a truck on Sunday, Sgt. Kerry Schmidt said.

“Who knows how many more crashes may have occurred in the day that were never reported.” he said. “We’ve seen far too often vehicles spinning out because they’re going too fast, because they’re over-correcting or panicking.”

Much of southern Ontario was under a weather advisory and snowfall warning as a messy mix of rain, ice pellets, freezing rain and snow battered the region.

High winds and ice buildup also led to power being knocked out for 25,000 Hydro One customers and 6,000 Toronto Hydro customers, the utilities said.

Multiple communities in southern Ontario also cancelled their Santa Claus parades due to safety concerns – including in Mississauga, Burlington, a small Hamilton community and a small Waterloo community.

Authorities in Burlington said the parade wouldn’t be rescheduled because of the complicated logistics involved.

“Unfortunately, the parade cannot be rescheduled due to the massive amount of scheduling to co-ordinate 90 floats and road closures,” city officials said on Twitter.

“We encourage all residents to please avoid unnecessary travel today.”

Environment Canada said the threat of freezing rain extended into the nighttime in the Niagara Region and Hamilton, while more snowfall is expected in Kingston and the Bruce Peninsula.

And in the US

The National Weather Service issued winter storm warnings and predicts heavy snow and freezing cold in swaths of New England and New York. Ice accumulations are predicted in parts of Pennsylvania.

More than a foot (0.3 metres) of snow is expected in parts of upstate New York eastward to southern Maine. New York Gov. Andrew Cuomo cut short a trip to Puerto Rico to return home and deal with the storm.

The system, which has been pummeling the US since before Thanksgiving, has already dumped heavy snow from parts of California to the northern Midwest and inundating other areas with rain.

Authorities found the bodies of two young children in central Arizona after a vehicle was swept away while attempting to cross a runoff-swollen creek. A third child is missing.

A storm-related death also was reported in South Dakota.

Blizzard conditions buffeted the High Plains on Saturday.

The city of Duluth, Minnesota, was blanketed with 19.3 inches (5.9 metres) of snow as of 6 a.m. Sunday. The city issued a “no travel advisory” at noon Saturday and deemed the storm “historic.”

Farther south, precipitation was in the form of rain and thunderstorms.

Forecasters said a new storm is expected to bring several feet of mountain snow, rain and gusty winds to California through the weekend. Another system is forecast to develop in the mid-Atlantic Sunday, moving into a nor’easter by Monday.

As the storm shifts east, flight delays and cancellations are continuing to pile up – disrupting travellers heading home after Thanksgiving.

As of 10 a.m. Sunday, 53 flights were delayed and 6 were cancelled at the three New York-area airports, according to the flight tracking website FlightAware.

The Federal Aviation Administration said some flights heading to Newark, New Jersey, are being delayed by an average of more than 2 1/2 hours.

There were also dozens of delays at airports in Chicago and Minneapolis.

At Denver International Airport, there were 100 flights cancelled Saturday because of high winds.

Authorities in the western states were still grappling with the aftermath of heavy rains and snow over the busiest travel weekend of the year.

Families in California took advantage of the early season snow in the Grapevine area, sledding down slopes in Frazier Park, California. Traffic was heavy, but Interstate 5 was open in both directions as holiday travellers headed home.

High winds and ice were making travel almost impossible in some other places, however.

A 100-mile (160.93-kilometre) section of Interstate 80 in Nebraska and Wyoming closed Saturday morning because of high winds and blowing snow. Several other roads and highways also were closed.

Back-to-back snowstorms and strong winds combined to seriously complicate travel by land across much of the rest of Wyoming, where roads were closed in the eastern and southern parts of the state because of whiteout conditions.

Travel was also difficult in Colorado Saturday as winds blew around snow that fell in previous days.

Northeastern Colorado roads were closed due to strong winds, blowing and drifting snow and poor visibility.

In northern Montana, more than a foot of fresh snow and strong wind gusts are expected to combine to create ground blizzard conditions along the Rocky Mountain front.