Which risk increases when lahars encounter drainage constrictions?

💡 Explanation

Increased hydraulic dam breaching occurs because constriction causes increasing lahar depth which greatly raises hydrostatic forces; a dam forming upstream fails; therefore catastrophic outburst floods occur downstream; rather than merely a contained sediment deposition.

• Which outcome occurs when glacial sediment is efficiently lifted far away over land, followed by "frost shattering"?
• Which risk increases when earthquake-induced liquefaction occurs beneath a coastal levee?
• Which outcome occurs as rainwater percolates karst layers?
• Which process contributes to the formation of deep anoxic basins within fjord environments with restricted sills?
• During a volcanic eruption, which consequence results when sustained pyroclastic surges encounter prolonged rainfall?
• Which flooding consequence occurs when an alluvial fan's sediment transport pathway becomes overloaded?