Spring Ice Jams
Each winter, the surface of the Saint John River gradually freezes as temperatures drop, forming layers of ice that can stretch for miles along the river. Ice formation is influenced by factors like air temperature, water flow, and snow cover, which can insulate or protect the ice. As spring arrives, melting snow from the River Valley causes river levels to rise, putting pressure on the winter ice and leading to its break-up.
Sometimes, the broken ice pieces can pile up in narrow sections of the river, forming what is called an ice jam. These temporary natural “dams” can slow the flow of water, causing it to back up along the river and nearby low-lying areas. In some years, these ice jams have been strong enough to cover roads, yards, and even properties. When this happens, heavy machinery is often brought in to push the ice away and restore safe passage.
Ice jams have also shaped the history of the Hartland Covered Bridge. In 1920, an ice jam at the Somerville end of the river destroyed two spans of the then-uncovered bridge. When the spans were replaced, a decision was made to cover the structure. The bridge reopened in 1922 as the covered bridge we know today, standing as both a vital crossing and a reminder of the river’s seasonal power.