A flood is an abnormal progressive rise in the water level of streams or rivers which may result in overflowing. When an area which is normally dry land becomes partially or completely submerged due to rise in water level, flooding has also occurred. Floods in the Caribbean can often be caused by heavy rainfall, dam or levee failures, tsunamis, unusually high tides, storm surges or burst water mains.
Flash floods can occur within a few minutes or hours of excessive rainfall, a dam. Flash floods often have a dangerous wall of roaring water carrying rocks, mud and other debris.
Overland flooding, the most common type of flooding event typically occurs when waterways such as rivers or streams overflow their banks as a result of rainwater and cause flooding in surrounding areas. It can also occur when the capacity of underground pipes, or the capacity of streets and drains designed to carry flood water away from urban areas are exceeded.
Flooding is the most common natural hazard and it can occur in different ways. Take a look below to find out more about the different types of flooding.
There are four types of flooding that affect Saint Vincent and the Grenadines and the wider Caribbean:
Flash floods are the result of heavy rainfall or cloudburst over a relatively small drainage area. Flash floods carry highly destructive flood waves and are most common in mountainous areas or in steep places that have streams flowing though narrow canyons.
These occur when a large amount of rain falls in river systems with tributaries that drain large areas containing many independent river basins. They may last a few hours or many days depending on the intensity, amount and the distribution of the rainfall.
This results when large bodies of water, like the sea or lakes, overflow onto bordering lands. They are mainly caused by high tides, the heavy rains that accompany hurricanes, waves created by high wind surges created by storms, and long waves produced by earthquakes out at sea.
This is a slow build up of water in depressions, sinks, areas with clay base soil, and slow percolation rate
The following are main causes of flooding in Saint Vincent and the Grenadines
Flooding is also a natural feature of drainage systems and of rivers and streams. It occurs when drainage channels are filled and the rivers and streams can no longer accommodate the excessive water generated by severe weather conditions. The drainage channels then overtop their natural or artificial banks and water enters the surrounding lands to cause flooding.
Also human activities, which damage the environment, for example, sand mining, deforestation and poor garbage disposal, increase the risk of flooding.
Areas most likely to be worst affected by flooding are:
Persons who live close to these areas are urged to be on the alert in case of a disaster as they are most vulnerable to flooding.
A flood can come at any time and they can be very destructive. Be ready! Preparation is half the battle.
If a flood is likely in your area, you should:
If you must prepare to evacuate, you should do the following:
Flooding can often cause forced evacuation. The process of evacuation is normally affected to remove a threatened community from a high risk factor.
The evacuee is often being asked to leave the security of his/her home to an impersonal setting. This is often in the form of shelters - located at some schools and churches.
Secure all personal documents and records. Since the duration of the stay away from home is unpredictable gas, electricity and water should be turned off.
If you have to leave your home, remember these evacuation tips:
Cars can become coffins in floods so driving should be undertaken only when absolutely necessary- for instance evacuation of persons unable to walk.
The following are important points to remember when driving in flood conditions:
Follow evacuation orders carefully.