Winter is especially dangerous for ice jam-related flooding

In the winter or early spring, a combination of unseasonably warm temperatures, rain, snow on the ground, and ice jams on rivers and streams can be extremely dangerous. Ice jams can cause flooding by backing up water or abruptly releasing huge volumes of water when they break.

The main stem Susquehanna River is more prone to ice jams and subsequent flooding than any other river east of the Rocky Mountains.