Hanging Glaciers

A hanging glacier is a mass of glacier ice perched on a steep mountainside or in an elevated tributary valley, with its lower end suspended above the main valley. Its defining feature is an abruptly terminating ice front above a cliff, steep slope, lower glacier, or valley floor.

Diagnostic geographical characteristics

Hanging glaciers occur in rugged, high-relief terrain where topography prevents the ice from developing a continuous valley-floor tongue.

• They occupy steep rock faces, ledges, cirques, or elevated tributary valleys.
• Their terminus remains markedly above the main valley floor or trunk glacier.
• They are generally smaller and steeper than ordinary valley glaciers and may be fed by direct snowfall and snow avalanches.
• Steep gradients produce fractured ice, including crevasses and unstable ice blocks called seracs.

Relationship with glacial topography

One common setting is a hanging valley, formed where a smaller tributary glacier eroded its valley less deeply than the larger trunk glacier. A hanging glacier may occupy such an elevated valley, but the terms are distinct: one denotes ice, while the other denotes a bedrock landform.

• A sharp break in slope may make the glacier descend through an icefall or terminate at a cliff.
• Some hanging glaciers occur directly on mountain faces and need not occupy a classic hanging valley.

Disaster significance

The elevated and steeply inclined ice is susceptible to gravitational failure, especially where it is fractured or loses support.

• Detached ice can generate ice avalanches that entrain snow, rock, and debris.
• An avalanche entering a lake or confined valley can cause displacement waves, debris flows, or cascading downstream hazards.
• Hazard assessment therefore considers slope, ice volume, fracture patterns, and the settlements or lakes lying below.