A mystery Good Samaritan in Chicago paid for 70 homeless people to stay in a hotel as temperatures dropped as low as -32C.
The offer came after the Chicago Fire Department confiscated nearly 100 propane tanks given to a homeless community to keep them warm.
The department acted after one of the donated tanks exploded.
The Salvation Army were preparing to move rough sleepers from the tent city when the generous offer to put them up came through and they were all relocated to a nearby hotel.
Jacqueline Rachev, a spokesperson for the charity, told the Chicago Tribune : “Isn’t that wonderful? At least they’re warm and they’re safe.”
The kind gesture comes as the death toll from the polar vortex causing freezing temperatures in the US has risen to 21.
Tens of millions of Americans braved Arctic-like temperatures as low as -48C on Thursday that has paralysed the US Midwest.
Officials across multiple states linked numerous deaths to the frigid air.
Locals have been warned “not to breathe deeply” outside as the freezing temperatures have led to Lake Michigan to solidify with mesmerising effect.
The death toll rose from a previous 12 after at least nine more people in Chicago were reported to have died from cold-related injuries, according to Dr Stathis Poulakidas at the city’s John H Stroger Jr Hospital.