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What is a Flood?

Of all natural hazards capable of producing a disaster, a flood is the most common in causing loss of life, human suffering inconvenience, widespread damage to buildings, structures, crop, infrastructure, and other national assets.

Severe weather conditions which lead to intense rainfall such as tropical depressions and hurricanes often lead to flooding.

What are the Different Types of Floods?

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, for example, flooding in New Market.

What Causes Floods?

The following are the main causes of flooding in Jamaica:

  • Heavy rainfall resulting from tropical weather disturbances
  • Deforestation
  • Improper agricultural practices
  • Inadequate design of drainage channels and structures
  • Inadequate maintenance of drainage facilities, blockage by debris brought by floodwaters
  • Construction of settlements in flood plains

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 excess water generated by severe weather conditions. The drain channels then overtop their natural or artificial banks and water enters the surrounding lands to cause flooding.

Additionally, 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:

  • Low-lying coastal areas
  • Areas near gully banks
  • Flood plains of major rivers
  • Lower sections of closed limestone valleys (e.g. Newmarket)
  • Areas vulnerable to landslides
  • Low-lying coastal towns and villages

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.

What are the Effects of Floods?

Floods can:

  • Disrupt one's personal, economic and social activities.
  • Set back the nation's security and development by damaging or destroying roads, buildings and other infrastructure.
  • Cause death by drowning.
  • Lead to insufficient food supply, which can lead to famine.
  • Destroy crops and livestock.

Protect Yourself from Floods

  • Remain calm and take all necessary precautions.
  • Make sure you have a battery-operated radio with extra batteries. Follow all instructions. If told to evacuate move out of the house or building to safe, high ground.
  • Turn off all utilities at main switch if evacuation is necessary. Do not touch any electrical equipment unless it is in a dry area or you are standing on a piece of dry wood with rubber footwear and gloves.
  • Remove all valuables. Wrap all-important personal items, family documents electrical appliances, pictures and wall hangings in plastic bags.
  • Avoid already flooded areas. Do not attempt to cross any stretch of floodwaters on foot if the water is above your knees.
  • Cars can become coffins in floods. DO NOT drive where water is over roads as under those floodwaters the road could already be washed away and rapidly rising water could lift the car and carry it away.
  • Do not go sightseeing in flooded areas.
  • If caught in a house by suddenly rising water move to the second floor and or if necessary, to the roof. Take warm clothing and a flashlight with you – as well as battery radio. Wait for help.
  • Use only recommended routes if you must travel.
  • Listen to the radio for instructions.
  • When returning home and before, you enter the house, be sure that the structure is not in danger of collapsing:
    • move about the building slowly
    • do not touch electrical appliances or fixtures
  • Open windows and doors to let air circulate. This will help remove foul odors and protect you from escaping the gas. It will also help to dry out the house
  • Take pictures of damage both to the house and its contents for insurance purposes.
  • Get in touch with your insurance company – if the house is insured.
  • Begin to clean up as soon as possible. Throw out any perishable foods. They may be contaminated.
  • You may need to hose down furniture if mud is lodged on them.
  • Shovel out mud while it is still moist and dry rugs and carpets thoroughly.
  • Make necessary repairs to stop further losses from the elements or from looting.
  • Boil and store drinking water.
  • Keep garbage tightly sealed.
  • Cover and protect food.
  • Prevent mosquito breeding by punching holes in all containers in which water can settle.
  • Do not walk barefooted outside, during or after a flood. Wear water boots or shoes.
  • Do not go sightseeing in flooded areas.
  • Do not touch loose or dangling electrical wires.
  • Exercise caution when crossing bridges and passes that are near to rivers and streams. Use only recommended routes.
  • Bury all dead animals as soon as possible.
  • Do not go swimming in floodwaters.
  • Follow evacuation orders carefully.

Flooding often cause a 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.

The decision to evacuate is often a difficult one and at times may be resisted by residents, as they often have to leave behind their possessions unprotected. Moving to a shelter should be a last resort rather than a first priority. Thus, care and understanding should often be exercised when dealing with persons who are reluctant to move.

There are specific factors to be considered for an evacuation process:

  1. Critical facilities: Determine if these are located in vulnerable areas.
  2. Population: size and characteristics of the population to be moved, health status, vehicles required, and medical arrangements required.
  3. Communication: During the evacuation, communication is extremely important. This is often necessary to ensure that all evacuation activities are proceeding as planned. Since efficient communication is key CB Radios are often utilized.
  4. Route determination: The route should be selected based on the capacity to ensure free access and in cases where evacuation is over a long distance; all primary and alternate routes should be mapped.
  5. Personal documents and records: Family members evacuating the area should 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.