Know the official flood warning products
- Flood Watch is issued by the Bureau of Meteorology and provides a 'heads up' that flooding is likely.
- Flood Warning is issued by the Bureau of Meteorology and warns a community of flooding at a predicted height, time and location.
- Flood Bulletin is issued by the NSW SES to to warn a community of flooding at a predicted height, time and location and the expected risks, impacts, consequences and the safest actions to take.
- Evacuation Warning is issued by the NSW SES to warn a community of the potential to evacuate properties, risks to life and property and the safest actions to take.
- Evacuation Order is issued by the NSW SES to immediately evacuate at risk sections of the community from a flood threatened area and advises the safest actions to take.
- All Clear is issued by the NSW SES to advise the evacuated community that it is safe for people to return to the area and any residual risks.
Monitor your flood situation
You may not always receive an official warning before floods begin to impact you, therefore it is important to be aware of the flood situation in your local area.
Monitor the local situation by personally witnessing the height and rate at which floodwaters are rising; maintaining contact with other people in your local community and local radio stations to receive and share updates on the flood situation.
Monitor the likelihood of flash flooding
Severe Weather Warnings and Severe Thunderstorm Warnings issued by the Bureau of Meteorology warn of the possibility of flash flooding.
When flash flooding is likely, leaving low-lying homes and businesses (evacuation) well before flash flooding begins is the best action to take, but only if it is safe to do so . If you are trapped by rising floodwater, seek refuge in the highest part of a sturdy building. Stay there and call '000' (triple zero) if you need rescue.
Severe Thunderstorm Warnings
The Bureau of Meteorology issues Severe Thunderstorm Warnings whenever severe thunderstorms are occurring in an area or are expected to develop or move into the area during the next few hours. The warnings describe the area under threat and the particular hazards likely to be associated with the thunderstorms including flash flooding.
Severe Weather Warnings
The Bureau of Meteorology issues Severe Weather Warnings whenever severe weather is occurring in an area or is expected to develop or move into an area. The warnings describe the area under threat and the expected hazards. Warnings are issued with varying lead-times, depending on the weather situation, and range from just an hour or two up to about 24 hours.
Severe Weather Warnings are issued for:
- Sustained winds of gale force (63 km/h) or more
- Wind gusts of 90 km/h or more
- Very heavy rain that may lead to flash flooding
- Abnormally high tides (or storm tides) expected to exceed highest astronomical tide
- Unusually large surf waves expected to cause dangerous conditions on the coast
- Widespread blizzards in Alpine areas
A Flood Watch is issued by the Bureau of Meteorology if flood producing rain is expected to happen in the near future and flooding is expected to be above Minor level. A Flood Watch covers a river basin or catchment. The general weather forecasts can also refer to flood producing rain. You should be prepared to act should flooding occur.
A Flood Warning is issued by the Bureau of Meteorology when flooding is expected to occur or is happening. Flood Warnings provide a predicted flood level and time at which a river will reach that level. Flood Warnings are issued in relation to flood gauges which are situated at a certain point on a river. Flood Warnings may contain observed, peak or predicted river heights.
NSW SES Flood Bulletins
NSW SES Flood Bulletins provide information on likely flood consequences and what actions are required to protect yourself and your property.
Evacuation Warning – prepare to evacuate
When flooding is likely to cut evacuation routes or inundate property, the NSW SES issues an Evacuation Warning to indicate that you should get prepared to evacuate. Being prepared will allow you to respond quickly if an Evacuation Order is issued.
Interpreting Flood Levels
Flooding which causes inconvenience such as closing of minor roads and the submergence of low-level bridges. The lower limit of this class of flooding is the initial flood level at which landholders and/or townspeople begin to be affected in a significant manner that requires the issuing of a public flood warning by the Australian Government Bureau of Meteorology.
Flooding which inundates low-lying areas, requiring removal of stock and/or evacuation of some houses. Main traffic routes may be flooded.
Flooding which causes inundation of extensive rural areas, with properties, villages and towns isolated and/or appreciable urban areas flooded.
Interpreting river heights
Flood Warnings may contain observed, peak or predicted river heights, these are often referenced from a flood gauge at a certain point along a river.
Predicted River Height
The height (in metres) to which the river is predicted to rise at the river gauge referred to in the warning. The actual depth of flood water will vary across the floodplain. Knowledge of past flood events, as well as estimates of flood levels from flood studies, are used by local Councils, emergency services and landowners to determine which areas are likely to be flooded from the predicted river height. The accuracy of this prediction will depend on a number of factors, including the type of flood forecasting model and its input data. Predicted river heights are subject to forecasting error and are regularly updated as more information becomes available.
Observed River Height
Depth of water (in metres) at a river height measuring gauge located along the river. In most cases, a zero reading is the lowest water level that is reached during dry conditions. In many tidal areas, as well as a few inland areas, river levels are expressed in metres above mean sea level or Australian Height Datum (AHD).
Peak River Height
Highest river height (in metres) observed during a flood event at the specified site on the river.
Dam Failure Alerts
Dam failure alerts
In New South Wales dam safety is monitored in most circumstances by the owner of the dam. During heavy rainfall or a flooding upstream, high volumes of water can create additional pressure on the dam wall and may affect its structural integrity.
In some instances water can be released to relieve this pressure. Prescribed dams often have early warning systems for communities that lie downstream of the dam and close to the dam.
Some of these alert systems are below:
A White Alert can be advise if a structural defect has been detected (e.g. crack, piping) or heavy rainfall event.
An Amber Alert often accompanies an Evacuation Warning and advises that dam failure could be possible if storage continues rising or structural defect not fixed.
A Red Alert often accompanies an Evacuation Order and advises that dam failure is imminent or has occurred
Look out for each other when flooding is imminent