Trees ‘exploding’ across US as Arctic blast freezes nation Extreme cold, ice and heavy snow sweeping much of the US cause rare frost cracks in tree trunks, triggering sudden splits and falling branches that sound like gunshots and have gone viral online *** An intense Arctic cold wave has covered nearly two-thirds of the U.S. over the past week, bringing temperatures as low as minus 30 degrees Celsius in some areas and snowfall measuring dozens of centimeters. The severe weather has caused wides