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Hillslope debris flow

A hillslope debris flow is a shallow, fast-moving flow of soil and weathered material triggered by heavy rainfall on steep hillslopes. Unlike channel-bound debris flows that follow established stream valleys, hillslope debris flows can start on almost any sufficiently steep slope after intense precipitation.

What this data measures

The federal BAFU hillslope debris flow index map (Gefahrenhinweiskarte Hangmuren) highlights areas with elevated susceptibility based on slope, soil, and vegetation factors.

It is a national-scale indicator map and not a local engineering risk assessment.

How to interpret it

An address in a high-susceptibility area means the landscape factors are conducive to rainfall-triggered hillslope debris flows.

It is a screening indicator, not a prediction that a flow will reach a specific building.

Increasing rainfall intensity under climate change makes this hazard more relevant than historical records alone may suggest.

Data sources