Storm surge and storm tide
A storm surge is a raised dome of sea water typically 60km to 80km across and two metres to five metres above the normal sea level.
As a cyclone reaches the coast, the huge winds whip up the sea and push the dome of water over low-lying coastal areas. The waves and sea water can move inland quite quickly, damaging buildings and cutting off escape routes. Be aware, these events pose a high risk of drowning.
A storm surge is not the same as a tsunami. While wind-generated waves in deep water only cause water movement near the surface, the passage of a tsunami involves the movement of water from the surface to the seafloor.
The height of the storm surge will depend on the following:
- The intensity of the cyclone - the stronger the winds the higher the surge
- The speed of the cyclone - the faster the cyclone crosses the coast the higher the surge
- The angle at which the cyclone 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
If a cyclone crosses the coast at high tide, the flooding from storm surge will be at its worst. This is known as a storm tide.
Storm tide evacuation maps have been created for coastal communities in the Bundaberg Local Government Area.
To find out how to prepare for disasters, visit our Get Ready page.