Recent speculation online suggests trees 'explode' in extreme cold, particularly in the United States during winter storms. However, this is misleading. The Star reports that 'exploding trees' is a loud popping or cracking sound known as a 'frost crack.' This happens when temperatures drop rapidly, freezing and expanding the sap and water inside the tree's trunk. If this expansion is too quick for the bark, the wood splits with a loud crack, mistaken for an explosion.