Summer has come to an abrupt halt in parts of the Rocky Mountains as temperatures reaching into the 90s have plunged about 60 degrees in less than 24 hours.
A powerful surge of cold air from Canada is unleashing snow and damaging winds in several states Tuesday. The roller-coaster weather ripped up trees by their roots and knocked out power to tens of thousands in Utah. It piled up snow that shut down parts of the scenic road through Glacier National Park in Montana and a key highway in Wyoming. But the temperature drop is helping with wildfires in Colorado and Montana that had ballooned in hot, windy weather.