Metro Detroit Flood Watch: What's the difference between a flood and a flash flood?

Flooding is expected this week in Metro Detroit.

With heavy rain forecasted through Thursday, the area is already under a Flood Watch, with the potential for that to become a Flood Warning when the precipitation arrives. But what does that mean?

See the full forecast here.

A flood is when a normally dry area experiences an overflow of water from drainage ditches, rivers, or other bodies of water. Floods also include water that ponds where it was raining.

Floods can last days or weeks.

READ: Pump station could experience power issues when it rains this week

A flash flood describes when there is heavy rain and rapid flooding in a short period, usually less than six hours. They happen within minutes or hours of excessive rain. A flash flood is also possible even if it doesn't rain because a failed dam could cause one.

According to the National Weather Service, flash floods usually include raging torrents that sweep up items.

MORE: Why do Detroit freeways keep flooding?

A Flood Watch or Flash Flood Watch means that your area could flood. 

A Flood Warning means that it is flooding or will flood.

A Flash Flood Warning means it is currently happening.