The "blizzard of the century" has left at least 25 dead in the state and caused US Christmas travel chaos.

The remnants of a massive sprawl of extreme weather that gripped the country over several days caused widespread power outages, travel delays and at least 47 deaths.

In New York state, authorities have described ferocious conditions, particularly in Buffalo, with hours-long whiteouts, bodies being discovered in vehicles and under snow banks, and emergency personnel going "car to car" to search for more motorists.

The perfect storm of fierce snow squalls, howling wind and sub-zero temperatures forced the cancellation of more than 15,000 flights in the US in the past week.

The epicenter of the crisis is Buffalo, a city that is no stranger to bad winter weather.

Governor Kathy Hochul said that it was too early to say that the storm was over.

Some western New York towns got up to 40 inches of snow.

According to a White House statement, Hochul spoke with President Joe Biden, who offered the full force of the federal government to support New York state.

The National Weather Service predicts up to 14 more inches of snow on top of the several feet that have already buried the city.

Poloncarz said he was "heartbroken" to report the death toll had risen to 25 county-wide.

According to Poloncarz, Erie's death toll will surpass that of Buffalo's notorious 1977 snowstorm.

He said that they expected more deaths from the storm.

With more snow in the forecast, he and Hochul warned residents to stay in place.

- 'Gut-wrenching' -

The National Guard and other teams have rescued hundreds of people from snow covered cars and homes without electricity, but more people are still trapped.

The Erie County Sheriff said the storm was the worst he had ever seen.

He told CNN that it was gut-wrenching when he got calls from families who said they were freezing.

Hochul said she was shocked by what she saw during the tour.

"It's like going to a war zone, and the vehicles along the sides of the roads are shocking," Hochul said.

She said it was a war with nature.

In Texas communities along the Mexico border, some newly arrived migrants have struggled to find shelter because of the extreme weather.

- Sweeping power outages -

According to tracker poweroutage.us, almost 1.7 million customers were without electricity on Saturday.

There were some 50,000 people without electricity on the US east coast on Monday.

Some Erie County residents were not expected to have power restored until Tuesday due to frozen electric substations.

The international airport in Buffalo is closed until Tuesday and a driving ban is in effect for much of Erie County.

Some of the nation's busiest transport routes were temporarily closed due to road ice and snow.

As the nation reached what is usually its busiest time of year for travel, drivers were being warned not to drive.

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