The US Midwest dug out Monday from a snowstorm that closed schools and businesses, as millions braced for dangerous sub-zero temperatures that could shatter records. School districts in Minnesota and Wisconsin canceled classes and government offices, universities and businesses shuttered, with the mercury expected to drop to a polar -40 Fahrenheit (-40 Celsius). “Dangerously cold and potentially record breaking temperatures and wind chills are expected by Tuesday and Wednesday,” National Weather Service (NWS) said.