Winter has brought freezing temperatures and heavy snow to many parts of the world. Along with the cold comes a strange noise: loud cracking sounds from trees. Some viral videos claim trees are "exploding" in the cold. Experts say this isn’t true. What is heard is called frost cracking. John Seiler, tree specialist at Virginia Tech, told CNN, "They’re not actually exploding, at least not in the way the phrase suggests." When temperatures drop suddenly, water and sap in trees freeze and expand. This causes stress inside, especially when the bark cools faster than the wood beneath. Doug Aubrey from the University of Georgia explained, "That water expands as it freezes, and it can happen usually under very, very drastic drops in temperature." The bark shrinks quicker than the inner wood, leading to pressure that splits the tree’s layers, causing loud cracks. Bill McNee from Wisconsin DNR compared it to ice cubes expanding quickly in a freezer. The sounds can be startling, sometimes like gunshots. But such frost cracks are mostly harmless. McNee said, "While frost cracks can be loud and cause branches to fall off, it would be extremely rare for a tree to fully explode because of it." Often, the cracks heal when temperatures rise. Simon Peacock, an arborist in Canada, told CBC, "The break doesn’t harm the tree and will heal when the temperature warms up in the summer." Some tree species like maples, lindens, and birches with thin bark are more prone to frost cracking. Non-native trees are also at higher risk in very cold areas. Most trees survive winter well because they reduce their internal water and enter dormancy. Eric Otto from Minnesota DNR said, "A tree has thousands of vessels, or pipes, so if one bursts, the tree can continue to function." Experts assure that while the sounds may be loud and unusual, frost cracks are normal responses of trees to cold and do not signal danger.