Landslide response

What a landslide sounds and looks like before it arrives

Some landslides give warning. Others do not. USGS identifies several indicators that one may be developing or approaching. Recognizing them while there is still time to act is the difference between evacuation and entrapment.

Sound. A low rumbling that gets louder, like a passing freight train. Trees cracking. Boulders knocking together. Shaking brush. USGS compares the sound of a rapidly moving landslide to a low-flying jet.

Ground. The ground feels like it is vibrating. New cracks appear in pavement, foundations, or yard soil. Retaining walls, fences, or utility poles begin to tilt. Doors and windows stick for the first time.

Water. A stream or creek suddenly becomes muddier than normal, which can mean a large amount of new material has entered upstream. Or a stream stops flowing entirely, which may mean debris has blocked the channel upstream. If that natural dam fails, stored water and debris can rush downstream.

Ready.gov warns that by the time you are certain a debris flow is coming, it may already be too late to get away safely. The warning signs matter most during prolonged heavy rain, on slopes near recent wildfires, and in areas with known landslide history.

Go up and move downhill-side

USGS guidance is direct: if a landslide strikes while you are inside a building, do not evacuate during the slide. Go to the highest floor. If you are in a single-story home, climb onto a kitchen counter, desk, or sturdy table and hold on.

Move to the downhill side of the building. Debris pushes through uphill-facing walls and windows first. The downhill side of the structure gives you the most distance from the incoming material.

Do not go to the basement. The basement is the first space to fill with debris and water. This is the opposite of tornado guidance, which sends people to the lowest interior room. Landslides move horizontally and downhill; tornadoes move vertically. The two hazards require opposite shelter positions.

Landslides can occur in pulses. The first wave may not be the last. Stay where you are until you are certain the slide has stopped and it is safe to move.

Run perpendicular, not downhill

If you are outside when a landslide begins, USGS advises running away from the sound to the right or left. Do not run uphill (toward the source) or downhill (in the slide's path). Landslides travel downhill and are much faster than a person.

If rocks and debris are approaching and you cannot get clear, run for the nearest shelter: a group of trees, a building, or any solid structure. If escape is not possible, curl into a tight ball and protect your head.

Ready.gov adds specific guidance for roads: never cross a road with water or mud flowing across it, and never cross a bridge if you see a flow approaching. Debris flows can grow faster than expected, and a bridge that looks passable one moment can be overwhelmed seconds later.

If you are driving and encounter a slide, do not try to drive through it. Turn around and find an alternate route. If you are caught in debris while in a car, stay in the vehicle, curl below the windows, and protect your head.

Stay away and report

Stay away from the slide area after the initial event. More slides can follow, especially during continued rain. USGS notes that landslides often occur in pulses, and the slope may remain unstable for days or weeks.

Report the landslide immediately to local authorities. Check for injured or trapped people near the slide area without entering the debris field yourself. Flooding often follows landslides because both can be triggered by the same prolonged rainfall event, or because the slide has dammed a stream.

Check your home's foundation, chimney, and surrounding land for damage before re-entering. Even a few inches of slope movement can break water, sewer, and gas lines. Report broken utilities so they can be shut off before creating additional hazards.