What is a Flood?

A flood is defined as an overflow or inundation of water from a river or other body of water which causes or threatens loss of life and property and environmental damage.

The severity and frequency of flooding is influenced by:

• extreme rainfall
• high temperatures causing rapid snow melt
• high temperatures causing ice break-up
• storms with high winds
• soil moisture conditions
• ice jams – especially during winter mild spells and spring thaw
• Windchill conditions that produce significant frazil ice, which is slush consisting of ice crystals that form in water that is too turbulent to freeze over

The low lying area surrounding a lake or river, not normally under water, is known as a floodplain and is part of the water body’s natural living space. Floodplains can be mapped and designated as areas likely to experience repeated flood activity.

Flooding can also affect the operation of utilities which may affect community stability and its economy.

• Conservation Ontario   provides a list of Conservation Authorities across the province which provide flood messages.
• Emergency Management Ontario has a number of factsheets, including preparing an emergency survival kit, evacuation and dealing with pets, children and the elderly during an emergency.
• Environment Canada provides weather warnings across Ontario.
• Surface Water Monitoring Centre