A powerful winter storm that brought severe frost and heavy rainfall swept most of the United States, which is home to about 250 million people.
Severe weather warnings are in effect in 12 US states.
On Tuesday, frosty weather came to the northwest of the country, and then moved to the east.
On Friday, as forecasters warned, the storm turned into a so-called explosive cyclone - a natural phenomenon observed in the middle latitudes, when the cyclone sharply intensifies during the day, atmospheric pressure drops rapidly.
Severe frosts, squally winds and heavy snowfalls have already caused the death of 19 people.
More than one and a half million people in the country were left without electricity, hundreds of flights were canceled last Friday.
A powerful winter storm covered an area of 3200 km - from Texas to Quebec.
\"Explosive cyclone\" brought heavy snowstorms to the US-Canada border, to the Great Lakes region.
Much of Canada was also in the grip of a winter storm.
In Ontario and Quebec, severe frosts have led to power outages in homes where hundreds of thousands of people live.
Most of Canada - from British Columbia to Newfoundland - was in severe cold.
Residents are being warned of further worsening weather.
The US National Weather Service said that this is the first such large-scale onset of cold weather in the history of observations.
Almost the entire territory of the country was in the grip of a winter storm.
The temperature in Montana on Friday dropped to -45 degrees Celsius.
In Michigan on Friday night, the temperature dropped to -17 degrees Celsius.
Heavy snowfall is forecast for Pennsylvania.
In Seattle and Portland, residents skate on the icy glaze that has covered city streets.
Meanwhile, in coastal areas - New England, New York and New Jersey - there is a flooding of the coastline.
Even farther south - the states of Louisiana, Alabama, Florida and Georgia - received warnings of a significant drop in temperatures.
In South Dakota, Native American tribes were forced to burn their clothes to keep warm after running out of fuel.
\"If precautions are not taken, cold winds at this temperature can cause frostbite in less than five minutes, and prolonged exposure can lead to hypothermia and death,\" the meteorologists warned.
In the city of Buffalo, 89 cm of precipitation fell.
Visibility due to snowfall in the city is almost zero.
Meteorologists urged local residents to stay out of the street if possible and refuse to travel by car.
Among the victims of the winter storm are people who died in road accidents.
The situation on the roads has become much more complicated due to weather conditions.
So, in the state of Ohio, 50 cars collided at once, four motorcyclists became victims of a major accident.
Nearly 6,000 flights were canceled on Friday in the US.
It also became known about the cancellation of 1200 flights on Saturday.
Deteriorating forecasts mean that many Americans will miss their Christmas plans.
Meteorologists say that such weather is observed in the United States every few decades.