Flood waters can destroy the land, washing away roads, bridges, railway tracks and buildings. Crops can be ruined and livestock drowned. Lives are also at risk, particularly in flash floods.
Floods are one of New Zealand’s most frequent emergency events. They happen when storms and heavy rain make rivers overflow their banks or drainage systems overflow into the streets.
Normal rainfall soaks into the soil, is taken up by trees and plants, and runs off the land to form our streams and rivers. Floods happen when there is too much water and the run-off is too much to be carried by the rivers.
There are four main types of flood:
Flood waters can destroy the land and wash away or damage roads, bridges, railway tracks and buildings. Crops can be flooded and livestock drowned. People have to take care and be prepared, particularly in flash floods where fast-flowing water filled with debris can sweep people away. The waters can even be strong enough to pick up vehicles.
After a major flood there will be a lot of damage and pollution to clean up. It may take months or years to recover.
Only return home once you are told it is safe to do so.
Don't go sightseeing through flooded areas.
Do not drink floodwater. It could be contaminated.
Find out more about what to do before, during and after a flood.
Are you ready in case a flood occurs?
Find out about the worst flood in your area and how high the flood waters reached. Record this height and share it with your family — would it reach your home?
Make a plan with your family to get through an emergency. Think about the things you need every day and work out what you would do if you didn't have them.
Make your plan — print it out, stick it on the fridge and make sure everyone knows the plan.
Find out about past floods that have happened in your region.
Floods 101 is part of a series of natural disaster videos produced by National Geographic.
A map of a local area allows the user to adjust floodwaters to show how much of the land could end up under sea level.
STEM-Works have a series of learning experiences that focus on floods and tsunami.
A New Zealand perspective on floods from Te Ara, the Encyclopedia of New Zealand.
Earthquakes, floods, landslides, storms, tsunami and volcanic activity can be frightening because they can strike at any time and often without warning. Explore the types of emergencies below and learn better ways to prepare.