The First Warning 13 Weather Team takes an in-depth look at ice jams! Ice jams happen when rivers freeze in the winter, then a big thaw along with heavy rain occurs. The ice on the river breaks up and flows downstream. Inevitably, the massive ice chunks get backed up around bends in the river or where they narrow. This causes the water behind the ice to flood local areas. Some of our most significant winter floods were started by these ice jams. We’ll discuss this phenomenon and what causes them to wreak havoc on parts of the Capital Region.