We know that flooding can occur during periods of heavy rainfall. But what actually takes places above and below ground, and how is it different from normal rainfall conditions?
Our interactive graphic below will help you understand.
Click on the "Show/hide flood conditions" button to see either normal or flooding conditions. Click on the "Captions" button to see descriptions for what is happening in normal and flooding conditions.
What is the difference between flooding and non-flooding rainfall conditions?
In normal conditions (i.e. no rain, or normal rainfall levels):
frozen state: water is captured as ice and snow
soak it up: groundwater is absorbed by the soil
baseflow: groundwater flows into rivers and streams
up and away: water moves back to the atmosphere through plant action and evaporation.
When floods happen:
rain falls: rain falls, adding to surface water runoff and saturating ground
snow melts: snow melts, adding to surface water runoff and rising streams/river waters
groundwater rises: excess rain soaks into the ground, saturing groundwaters
rivers rise: water from rain, melting snow and surface water runoff cause rivers to rise
homes wrecked: rising waters damage property and infrastructure.