Lesson · Geotechnical & Slope Stability

Recognizing Landslide Precursors

The observable signs that a slope is moving — tilted trees, new springs, cracking ground, changed stream turbidity — and how to act on them before the failure itself.

  • General Public
  • Teacher
  • Student
  • Visitor
  • Responder

Learning objectives

  • List the observable precursors that indicate slope movement is underway.
  • Explain why sudden changes in spring or stream behaviour signal subsurface movement.
  • Describe the relationship between antecedent rainfall and slope failure timing.
  • State what to do when precursors appear but no official warning has been issued.

In the field

Ordered, and meant to be workable under pressure. Numbered because the sequence matters.

  1. Walk the slope above your home after heavy rain and look for new cracks, bulges, or tilted trees.
  2. Note any spring that appears where there was none, or any stream that suddenly runs muddy.
  3. Photograph and date cracks so movement between visits is measurable rather than remembered.
  4. Leave and report to local authorities when precursors appear — do not wait for an official warning.
  5. Sleep on the side of the house away from the slope during periods of sustained rainfall.

Sources · 3

The tag under each source states what was actually checked. “Authority named · URL not re-resolved” means the issuing body and document are named, but the link was not re-resolved for this lesson. It is not a claim of verification, and the authority’s own current bulletin always supersedes anything here.