At least seven deaths have been linked to the freezing temperatures across the Midwest, NBC News reports. The deaths include an 82-year-old Illinois man who died of hypothermia outside his home, an Illinois man who was struck by a snowplow, and a Milwaukee man who was found frozen to death in a garage. The deep freeze has brought record-breaking temperatures with it and has forced the U.S. Postal Service to take the rare step of postponing mail delivery in large parts of the region. Almost 1,000 flights were preemptively canceled in Chicago, where temperatures dropped to minus 19 degrees early Wednesday which broke the previous daytime record low which was set in 1966. “These (conditions) are actually a public health risk and you need to treat it appropriately,” Chicago Mayor Rahm Emanuel said Tuesday. “They are life-threatening conditions and temperatures.” The National Weather Service warned that a wind chill of minus 25 can freeze skin within 15 minutes.