How do snowmelt and rain trigger river ice breakup?

Snowmelt and rain trigger river ice breakup primarily by increasing the volume of runoff entering the river system. This additional water raises the river's water level, which can physically lift the ice and break it loose from the banks.12

Furthermore, the increased flow exerts greater mechanical forces on the ice cover. When these forces exceed the structural strength of the ice, the cover breaks apart and is transported downstream. This process is particularly significant during spring in northern regions or midwinter thaws in temperate areas, where the influx of water acts as the primary driver for moving ice that has already begun to deteriorate due to rising air temperatures and solar radiation. If the quantity of moving ice exceeds the river's transport capacity, it can accumulate to form an ice jam, which may lead to localized flooding.12