Which effect arises from a lahar encountering a constricted river valley located downslope?

💡 Explanation

Backwater flooding occurs because the valley constriction acts as a hydraulic control, causing the lahar to pool upstream via flow retardation, rather than moving freely. Therefore, flooding occurs; distal deposition is not directly linked to river constrictions.

• Which outcome occurs when upper tropospheric winds accelerate due to temperature differences across Hadley cell boundaries?
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• Which geomorphic feature accumulates landward due to drift?
• Which phenomenon prevents cave formation at greater depths?
• Which consequence results when soil aridity increases with unrestricted grazing?
• Which increasing risk to alpine communities results when permafrost thaw amplifies seismic ground motion?