Bone-chilling cold gripped much of the central US as 2018 began, leading to at least two deaths attributed to exposure to the elements.
The National Weather Service issued wind chill advisories covering a vast area from south Texas to Canada and from Montana and Wyoming through New England.
Dangerously low temperatures enveloped much of the Midwest yet did not deter hundreds of people from ringing in the new year by jumping into Lake Michigan.
Despite sub-freezing temperatures and a warning of potential hypothermia from the local fire chief, throngs of people took part in the annual tradition in Milwaukee, warming up later with heat from a beach fire pit.
A similar event was cancelled on the Chicago lakefront, where temperatures dipped below zero as thick white steam rose from the lake on Monday morning.
Organisers said the arctic blast made jumping into the lake too dangerous.
Instead, would-be Chicago plungers had their pictures taken while jumping on the frozen beach – in their swimsuits.
Temperatures plunged below zero elsewhere in the Midwest, including in Aberdeen, South Dakota, where the mercury dropped to a record-breaking minus 32F (-36C). The previous New Year’s Day record had stood for 99 years.
In Nebraska, temperatures hit 15F below zero (-26C) before midnight on Sunday in Omaha, breaking a record low dating to 1884.
Omaha officials cited the forecast in postponing the 18th annual New Year’s Eve fireworks spectacular that draws about 30,000 people.
It was colder in Des Moines, where city officials closed a downtown outdoor ice-skating plaza and said it would not reopen until the city emerged from sub-zero temperatures.
The temperature hit 20F below zero (-29C) early on Monday, with the wind chill dipping to negative 31F degrees (-35C).
In north-eastern Montana, the wind chill readings dipped as low as minus 58F (-50C).
Plunging overnight temperatures in Texas brought rare snow flurries as far south as Austin and accidents racked up on icy roads across the state.
It was even cold in the deep south, a region more accustomed to brief bursts of arctic air than night after night below zero.
Frozen pipes and dead car batteries were concerns from Louisiana to Georgia as overnight temperatures in the teens were predicted across the region by Monday night.
The Milwaukee County Medical Examiner’s office said two bodies found on Sunday showed signs of hypothermia.
They included a man in his 50s found on the ground in an alley and a 34-year-old man.
Police believe the cold weather also may have been a factor in the death of a man in Bismarck, North Dakota, whose body was found near a river.