(WUTR/WFXV/WPNY) – Today’s theme for Winter Weather Awareness Week goes over winter-time flooding. While flooding may not be the first thing that comes to mind when thinking about snow and ice, it’s a fairly common event, and can happen in ways you might not expect.
As colder weather ramps up, the edges of rivers start to freeze. That ice can break apart and move downstream. If there’s any sort of obstruction or blocking in the water flow, the ice can build up, forming what’s known as an ice jam. When this occurs, water can be held back, causing upstream flooding. When the jam finally breaks, typically because the ice is melting, flash flooding can occur. This is because all the water and debris that was trapped is now free to rush downstream.
It only takes ice that’s six inches thick to destroy large trees and knock houses off their foundations which is why it is important to know when a nearby river is impacted by an ice jam and avoid the area until the ice jam has been resolved. You can keep track of it in your area through river forecasts here.
Flooding can also occur when the ground becomes frozen. This is because a frozen ground prevents rainfall and melting snow from absorbing/permeating into the ground. The water has nowhere else to go and becomes runoff which can flow quickly into other areas and build up.
Lastly, warmer temperatures that melt snow can also lead to flooding, especially if there is already a buildup of snow on the ground. Heavy rainfall can also add to the amount of melted snow, enhancing the risk of flooding.