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, and 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. You can listen on your phone and it’s a good idea to have a battery powered radio.
• 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 storm surge or coastal flooding is a risk, you need to be prepared to follow the advice of local authorities and be ready to leave your home quickly.
• Evacuation may be necessary based on predicted wind speeds and water levels. The safest option is to decide early if you are going to leave.
• 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. If it’s flooded, forget it.