Floods

Flooding can happen anywhere, at any time, and can be caused by more than just rain. Even if you don't live near a river or creek, different types of flooding may still happen in your area from other causes.

On this page:

Head to the Flood - Plan and stay safe page to know what to do when a flood occurs.

Information about floods - Types of flooding

Riverine flooding

In riverine flooding, relatively high water levels overtop the natural or artificial banks of a stream or river. The nature of riverine flooding can vary significantly in terms of cause, timing and depth between different locations. Coastal rivers with short, steep headwaters often have floods that rise and recede quickly. Inland floods with low gradients have floods that move slowly down the river, sometimes lasting for several months.

Flash flooding

Flash flooding occurs when soil absorption, runoff or drainage cannot adequately disperse intense rainfall, and is usually caused by slow-moving thunderstorms. Flash floods are generally defined as developing in six hours or less from rainfall to the onset of flooding.

Dam failure

Although dam failures are rare, their effects can be significant. In Victoria dam safety is monitored, and warning arrangements are in place to warn downstream residents of potential dam failure threats. Should a dam failure occur, significant downstream flooding can involve potentially swift flowing water and high amounts of debris.

Storm surge

Storm surge occurs when sea levels are elevated above the usual tidal limit due to the action of intense low pressure systems over the open ocean. The low pressure causes sea level to rise as there is less air pressing down on the sea. Combined with gale force onshore winds, this can lead to flooding of low-lying coastal land.

What to do during a flood

Flash flooding can occur quickly due to heavy rainfall and you may not receive an official warning. When riverene flooding is predicted, decide what you will do before flooding occurs. 

 Here's what to do if a flood occurs near you:

  • Floodwater is dangerous. Stay safe by never entering floodwater.

  • Call 132 500 for emergency assistance from VICSES.

  • Call Triple Zero (000) in life-threatening emergencies

  • Stay informed – monitor weather warnings and forecasts at the Bureau of Meteorology website, and warnings through the VicEmergency app, website and hotline (1800 226 226).

  • If you are inside:

    • Stay inside and be aware of rising floodwater.

    • If floodwater comes inside, move to a higher point such as a kitchen bench or second storey.

    • Contact family members and neighbours to ensure they are aware of the situation, if safe to do so.

  • If you evacuate from your home or workplace:

    • Remember to take your pets, mobile phone, spare clothes, mask and medications.

    • Turn off gas and electricity at your home or workplace.

    • Travel to the home of family or friends who are in a safe location, away from flooding.

    • Check for road closures when you leave and follow instructions from emergency services.

  • If you are outside:

    • Stay away from trees, drains, low-lying areas, creeks, canals, culverts and floodwater.

    • Seek shelter indoors, away from floodwater.

  • If you are driving when flash flooding occurs:

    • Stay safe by never driving through floodwater. It can take just 15cm of flowing water to float a car - That’s the height of an average pen.

    • Find alternative travel routes if roads or underpasses are flooded.

    • Be aware of driving hazards, such as mud, debris, damaged roads and fallen and damaged trees.

    • If driving conditions are dangerous, safely pull over on higher ground, away from trees.

    • Tune in to emergency broadcasters such as ABC local radio and designated commercial radio stations to monitor the situation.

Bureau of Meteorology warnings

 

  • Warnings are issued by the Bureau of Meteorology (BoM) to tell people about possible flooding.

  • Flood Watch means there is a developing weather pattern that might cause floods in one or two days.

  • Flood Warning means flooding is about to happen or is already happening. There are minor, moderate and major flood warnings. 

 

minor flood
A Minor Flood Warning means floodwater can:

 

  • Reach the top of the river banks.

  • Come up through drains in nearby streets.

  • Cover low-lying areas including riverside camping areas.

  • Affect some low-lying caravan parks.

  • Cover minor roads, tracks and low level bridges.

  • Spread across land or go into buildings on some properties and farms.

 

moderate flood warning
A Moderate Flood Warning means floodwater can:

 

  • Spill over river banks and spread across low-lying areas.

  • Start to threaten buildings, roads, rail, power and other developments.

  • Require evacuation in some areas.

  • Cover main roads.

 

Major flood
A Major Flood Warning means floodwater can:

 

  • Cause widespread flooding.

  • Threaten more houses and businesses.

  • Cause properties and whole areas to be isolated by water.

  • Disrupt major roads and transport routes.

  • Require many evacuations.

 

 

Severe Thunderstorm Warnings 

Thunderstorms are classified as severe when there is potential to cause significant localised damage through wind gusts, large hail, tornadoes or flash flooding. Severe Thunderstorm Warnings are issued to the community by BoM.

 

Severe Weather Warnings 

These warnings are issued to the community by BoM when severe weather is expected that is not directly related to severe thunderstorms or bushfires. Examples of severe weather include damaging winds and flash flooding.

Flash flooding happens quickly. Residents should listen out for warnings with flash flooding and remember that flash flooding:

  • Occurs so fast that it is difficult to provide a detailed warning. Often it arrives without warning.

  • Results from heavy rainfall during short severe storms.