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Storm surge

Storm surges—being prepared and staying safe

A storm surge is a raised dome of sea water typically 60km to 80km across and 2–5m above the normal sea level. They are caused by strong winds and areas of low pressure created by a cyclone or severe storm.

As the storm reaches the coast, huge winds whip up the sea and push the storm surge over low-lying coastal areas.

Storm surges can move inland quite quickly, damaging buildings and cutting off escape routes. There is a high risk of drowning.

A storm surge is not the same as a tsunami, or tidal wave. A storm surge comes in like a rapidly rising tide, but it can be extremely dangerous and destructive.

The height of the storm surge will depend on:

  • the intensity of the storm—the stronger the winds the higher the surge
  • the angle at which the storm crosses the coast—a right-angle crossing will increase the surge
  • the shape of the sea floor—the more gentle the slope, the greater the surge
  • local features such as bays, headlands or islands can funnel the surge and amplify its height
  • existing tidal conditions—if the cyclone crosses the coast at high tide, the flooding will be at its worst.

Preparing for a storm surge

There are some simple things that you and your family can do to stay safe and protect your property.

When a severe storm surge seems likely...

  • Listen to your local radio station for warnings and advice. Don't use your phone unless it is essential.
  • Prepare to move vehicles, outdoor equipment, garbage, chemicals and poisons to higher locations.
  • Decide which indoor items you will raise (e.g. furniture, clothing) or empty (refrigerators, freezers etc.) if your home may be flooded.
  • Check your emergency kit and consider what you will do with your pets.

If you need to evacuate...

  • If you decide to leave of your own accord, make sure you tell the police or your local State Emergency Service and your neighbours.
  • Make sure you pack warm clothing, essential medication, valuables, personal papers, photos and valuables in waterproof bags, to be taken with your emergency kit.
  • Raise your furniture, clothing and valuables onto beds and tables and into the roof space (place electrical items as high as possible).
  • Empty and turn off refrigerators and freezers, leaving the doors open to help prevent them floating about.
  • Turn off the power, water and gas and remember to take your mobile phone.
  • Put sandbags in toilet bowls and over all laundry/bathroom drain-holes to prevent sewage back-flow.
  • Lock your home (remembering to take your keys) and take the recommended evacuation routes for your area.
  • Don't drive into water of unknown depth and current.