The temperature was about 47 degrees Fahrenheit (8 degrees Celsius) in the early hours of Tuesday, according to a buoy that collects data for the National Oceanic and Atmospheric Administration.
Earlier, Kevin Cartwright, director of communications for the Baltimore Fire Department, told The Associated Press that several vehicles were on the bridge at the time, including one the size of a tractor-trailer truck.
He called the collapse a “developing mass casualty event,” though he didn’t know at the time how many people were affected.