Tides in Brisbane
Tides in the Brisbane River are normally within plus or minus 1.3m of Mean Sea Level, which is the average level for the surface of the ocean. However, twice a year, generally around January and July, tide levels may exceed this. These are commonly known as “king tides”. They are also known as higher-than-normal-high-tides.
While “king tides” can be predicted, higher-than-normal-high-tides can also occur periodically throughout the year. This usually occurs when abnormal weather and ocean conditions combine to raise water levels well above normal.
A storm surge occurs when a low-pressure system along with persistent strong winds force sea levels to rise much higher (or lower) than expected. Storm surge tides cannot be predicted with any degree of certainty.
Effects of higher-than-normal-tides
Not all higher-than-normal-high-tides cause impact, and many go unnoticed. However, any tide which is higher than normal, can cause localised tidal flooding, especially along the bayside and low-lying parts of nearby suburbs.
Areas connected to the foreshore and tide-affected areas of the river and estuarine waterways can also be affected when salt water spills over dry land. Roads may also be affected.
When combined with rain, higher than normal high tides can cause issues for local drainage systems, increasing the chance of localised flooding.
During periods of higher-than-normal-high-tides it is important to listen out for weather warnings and be aware of local conditions. Motorists should avoid driving through tidally flooded sections of road to avoid salt water damage to their vehicle.
Sandbags can be used to reduce the impact of flooding on your home or business. Information on where to access sandbags can be found here.
Find out more about whether your property and area may be at risk of flooding from tidal surges.
Information on tidal predictions at the Brisbane Bar can be found here.