winter storms pummelled the eastern US over the weekend, killing at least 10 people, including nine victims in Kentucky who died during flooding from heavy rains.

The National Weather Service warned of “life-threatening cold” into Tuesday, with temperatures in northeastern Montana predicted to dip as low as 45 degrees below zero (-42.7 degrees Celsius) with wind chills down to 60 below (-51 degrees Celsius).

Meteorologists said several states would experience the 10th and coldest polar vortex event this season. Weather forces in the Arctic are combining to push the chilly air that usually stays near the North Pole into the US and Europe. In Kentucky, Governor Andy Beshear said Sunday that the death toll rose to nine. “I am sad to share some more tough news tonight, Kentucky. We just confirmed another weather-related death out of Pike County, bringing our total loss to 9 people.”