Landslide & Mudslide Safety

Landslides and mudslides kill thousands of people every year across mountainous and hilly regions worldwide. In a single event, a debris flow can travel at over 50 km/h (30 mph), burying homes, roads, and entire villages with little warning. Unlike many disasters, landslides often give observable warning signs in the hours or days before they occur — knowing these signs can save your life.

Landslides are triggered by heavy rainfall saturating unstable slopes, earthquakes, volcanic activity, undercutting from rivers or coastal erosion, and human activity such as construction or deforestation. Mudslides (also called debris flows) are fast-moving slurries of water, soil, rocks, and vegetation that can travel kilometres from the original slope failure.

Warning Signs — Recognise the Danger

Environmental Warning Signs

Before and during a landslide, watch for:

Sign	What It Means
Cracks or bulges appearing in the ground	Slope is moving — may accelerate
Tilting trees, fences, or telephone poles	Ground has already shifted
Doors or windows sticking suddenly	Frame distortion from ground movement
New cracks in walls, foundations, or pavement	Structural movement underway
Changes in water flow — streams becoming muddy or drying suddenly	Slope movement is altering drainage
Sudden increase in stream or river flow	Upstream dam-up failure or accelerated drainage
Rumbling sound from hillside — growing louder	Debris flow is approaching
Smell of gas	Ground movement has ruptured a gas line

⚠️ If the ground is shaking, an earthquake may trigger an immediate landslide. Do not shelter near hillsides during or after an earthquake in landslide-prone areas.

Conditions That Dramatically Increase Risk

• Prolonged heavy rain (several days) followed by intense rainfall
• Rapid snowmelt combined with rainfall
• Earthquake shaking in mountainous terrain
• Wildfire that has destroyed ground vegetation in the past 5 years (root systems no longer stabilise soil)
• Steep slopes above 30 degrees
• Slopes that have had previous landslides

Before the Landslide Season

1. Know your risk area. Contact your local government or disaster management authority to find out if your home is in a landslide hazard zone. Look for historical landslide maps and steep terrain maps.
2. Learn your evacuation route. Know at least two routes out of your area that do not cross valleys, rivers, or the bases of steep slopes.
3. Inspect your property. Look for cracks in the ground, changes in drainage patterns, and evidence of past slope movement (disturbed vegetation, unusual mounds, tilted structures).
4. Plant ground cover on slopes. Vegetation root systems stabilise slopes — dense, deep-rooted plants significantly reduce slide risk.
5. Consult an engineer if you have cut slopes, fill slopes, or retaining walls on your property — get them assessed.

During Heavy Rain — Heightened Awareness

1. Monitor official weather and hazard warnings continuously during prolonged heavy rain events.
2. Be awake and alert during nighttime heavy rain — many deadly landslides strike at night.
3. If you hear rumbling or cracking sounds from a slope above you, do not wait to investigate — move away from the slope immediately.
4. Avoid river banks, stream channels, and valley floors during heavy rain — these fill first.
5. If roads cross under steep slopes or cross creek valleys, avoid them — culverts can block with debris, roads can be swept away.

If a Landslide Warning Is Issued

1. Evacuate immediately — take your go-bag, medications, and important documents.
2. Leave before roads become blocked — once a slide starts, roads can become impassable within minutes.
3. Do not go back to retrieve items.
4. Avoid river valleys and low-lying areas even if they seem distant from the slope.
5. Move to high ground — not just away from the slide, but up and away from valleys.

⚠️ Do not shelter in a vehicle near a landslide. Vehicles can be swept away easily. Your vehicle is also slower to manoeuvre out of the path of an approaching slide than a person on foot in many terrain situations.

If You Are Caught in a Landslide

If you cannot escape:

1. Move away from the path of the slide — try to get to higher ground or behind a large, solid obstacle like a concrete building or large rock.
2. Curl up tight if you cannot escape — protect your head and neck with your arms, bring your knees to your chest.
3. Hold your breath as the debris passes — the fine dust and mud in a debris flow can suffocate if inhaled.
4. After the slide, call for help immediately — call emergency services if you have signal; otherwise shout, use a whistle, or tap on pipes.

After a Landslide

Immediate Dangers

Hazard	Action
Subsequent slides	Move well away from the slide area — secondary slides are common
Unstable debris	Do not walk on landslide debris — it can shift and submerge you
Downed power lines	Stay well clear of any downed lines
Gas leaks	Do not use any switches; evacuate and call gas company
Blocked roads	Do not attempt to cross — debris may be deeper than it appears
Disrupted utilities	Assume water is contaminated; use stored or boiled water only

Search and Rescue

If people are trapped:

1. Do not enter the slide area yourself unless trained — you may be trapped as well.
2. Call emergency services immediately with exact location and number of trapped people.
3. If you can hear survivors, keep talking to them to maintain their mental state.
4. Look for voids and air pockets — survival is possible even under debris if an air space exists.

Returning Home

• Do not re-enter a home in or near a landslide area until authorities confirm it is safe and stable.
• Have a geotechnical engineer assess the stability of slopes and your structure before occupying.
• Document all damage with photographs before any cleanup.
• Report any new cracks, changes in drainage, or sounds from slopes to authorities.

Zones With High Landslide Risk

Region Type	Risk Factor
Mountainous and hilly terrain	Steep slopes and gravity are primary factors
Areas with heavy seasonal rainfall	Saturated soil dramatically reduces slope stability
Recently burned areas	Loss of root system stabilisation for 3–5 years post-fire
Areas near river undercutting	Erosion at slope base removes support
Coastal cliffs	Sea erosion and wave action undercut slopes
Areas with volcanic soil	Fine ash layers create weak planes within slopes

Quick Reference — Landslide Safety

Situation	Action
Ground cracks appearing	Leave the area immediately
Heavy rain for multiple days	Stay alert, monitor warnings, prepare to evacuate
Rumbling sound from slope	Move away from slope immediately — do not wait
Evacuation order issued	Leave immediately on your pre-planned route
Cannot escape slide	Move perpendicular to slide path, protect head, curl tight
After slide — smell gas	Do not use switches, evacuate, call gas company
Search and rescue needed	Call emergency services — do not enter slide area alone

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This guide is for general preparedness education. In an emergency, always follow the instructions of local emergency services. Landslide risk is highly site-specific — consult your local disaster management authority and a geotechnical professional for advice specific to your location.