Some landslides move slowly and cause damage gradually, others move so rapidly that they can destroy property and take lives suddenly and unexpectedly. Factors that contribute to landslides include saturation by water, steepening of slopes by erosion or construction and earthquake shaking.

Landslides are typically associated with periods of heavy rainfall and tend to worsen the effects of flooding that often accompany these events. In areas burned by fire, a lower threshold of rainfall may initiate landslides.

Debris flows, sometimes referred to as mudslides, are common types of fast-moving landslides. These flows generally occur during periods of intense rainfall. They usually start on steep hillsides as shallow landslides that liquefy and accelerate to speeds to about 16km/hr, but can exceed 50km/hr. The consistency of debris flows ranges from watery mud to thick, rocky mud that can carry large items such as boulders, trees and cars. Debris flows from different sources and can combine in channels, and their destructive power may be greatly increased. They continue flowing down hills and through channels, growing in volume with the addition of water, sand, mud, boulders, trees and other materials. When the flows reach flatter ground, the debris spreads over a broad area, sometimes accumulating in thick deposits that can wreak havoc in developed areas.

Prevention

Learn about the landslide risk in your area.
Develop an evacuation plan that details the route you will use to escape a landslide, and an alternative if your main route is blocked.
Discuss landslides and debris flow with your family.
If your property is in a landslide risk area, contact a company specialising in geotechnical engineering, civil engineering or structural engineering for advice on corrective and protective measures.
Become familiar with the land and structures around you so that you will notice any changes.
Watch the patterns of stormwater drainage on slopes near your home, and especially the places where runoff water converges, increasing flow over soil-covered slopes.
Plant ground cover and build retaining walls to limit the chances of a landslide.

Warning Signs

Doors or windows stick or jam for the first time.
New cracks appear in plaster, tiles, bricks or foundations.
Outside walls, walks or stairs begin pulling away from the building.
Cracks slowly develop and widening on the ground or on paved areas such as streets or driveways.
Underground utility lines break.
Bulging ground appears at the base of a slope.
Water breaks through the ground surface in new locations.
Fences, retaining walls, utility poles or trees tilt or move.
You hear a faint rumbling sound that increases in volume as the landslide nears. The ground slopes downward in one specific direction and may begin shifting in that direction under your feet.

Suspected Landslide

If you believe there is a real potential for a landslide to occur within a short period of time, call emergency services on Triple Zero (000). If you are unsure or there are no indicators of an immediate threat, contact us.
Inform affected neighbours as they may not be aware of potential hazards. Advising them of a potential threat may help save lives. Help neighbours who may need assistance to evacuate.
Evacuate. Getting out of the path of a landslide or debris flow is your best protection.

During a Landslide

Move quickly out of the path of the landslide or debris flow.
If escape is not possible, curl into a tight ball and protect your head.

After a Landslide

Stay away from the slide area as there may be a danger of additional slides.
Check for injured and trapped people near the slide, without entering the direct slide area. Direct rescuers to their location.
Help neighbours who may require assistance.
Listen to the radio and TV for the latest emergency information.
Watch for flooding, which may occur after a landslide or debris flow. Floods sometimes follow landslides and debris flows because they may be started by the same event.
Look for and report broken utility lines to authorities. Reporting potential hazards will get the utilities turned quickly and preventing further hazard and possible injury.
Check the building foundations and surrounding land for damage.
Replant damaged ground as soon as possible since erosion caused by loss of ground cover can lead to flash flooding.
Seek the advice of a geotechnical expert for evaluating landslide hazards or designing corrective techniques to reduce landslide risk. A professional will advise you of the best ways to prevent or reduce landslide risk.