A major winter storm has unleashed icy winds and heavy snowfall across large parts of the US, disrupting travel and leaving thousands without power.
The storms will be followed by a bitter cold arctic chill into the weekend, with temperatures dipping near -50F (-45C) in some areas.
Nearly 10in ((25.4cm) of snow in Iowa, where the 2024 election cycle kicks off on Monday, has upended campaign events.
Forecasters have called it a "life-threatening winter weather".
The National Weather Service (NWS) has issued weather alerts in nearly every state, as snow is in the forecast into Saturday from as far west as Oregon to as far east as Maine. More than 70 million people are under winter weather alerts.
Extreme weather has forced the cancellation of more than 2,000 flights as of Friday, most of which were scheduled to fly out of Chicago, according to flight-tracking service FlightAware.
Nearly 200,000 people are without power as of Friday evening, with Michigan and Wisconsin most affected.
Brian Hurley, a meteorologist with the NWS, told the BBC that midwestern states, including eastern Iowa, northern Illinois and southern Wisconsin, have already received between six to 10 inches of snow as of Friday evening.
Former President Donald Trump's campaign on Friday cancelled three out of the four in-person campaign events he was scheduled to hold over the weekend before the Iowa caucuses. Other candidates, including Nikki Haley and Ron DeSantis, have also had to cancel campaign events because of extreme weather in the state.