Weather authorities say an "epic, generational Arctic outbreak" caused record cold temperatures and life-threatening conditions in the northeastern United States on Saturday.
The summit of Mount Washington in New Hampshire reported a low of minus 78 Celsius (minus 108 Fahrenheit) — the coldest temperature ever recorded in the United States.
Meanwhile, the National Weather Service (NWS) in Caribou, Maine, said it received reports of "frostquakes."
"Just like earthquakes, [they] generate tremors, thundering sensations. These are caused by sudden cracks in frozen soil or underground water when it's very cold," the NWS office wrote on Twitter.
Strong winds also caused a tree branch in western Massachusetts to fall on a car, killing an infant, a district attorney said in a statement.
Homeless population braves record chill
Several cities in the Northeast set or tied record low temperatures for that date on Friday and Saturday. This created a significant risk for homeless people.
In Massachusetts, Governor Maura Healey took the unusual step of keeping the South Station transit hub open overnight so roughly 60 homeless people had a safe place to sleep.
"This is the coldest I ever, ever remember, and I worked the door at a bunch of clubs for 15 years," one person taking shelter at the station, who has been homeless since December 2021, told the Associated Press news agency.
Meanwhile, one of the city's main homelessness charities doubled the number of vans canvassing the streets on Friday and Saturday.
To the south, New York City issued a "code blue" alert, meaning no homeless shelter could turn anyone away.