BharatNotes Moraine
nounUsage in a UPSC answer
As Himalayan glaciers retreat under accelerating climate stress, the unstable moraine damming many high-altitude lakes threatens catastrophic outburst floods, compelling the State to integrate glacial-hazard mapping into its disaster-management framework.
Synonyms
Word Family
moraine (n), moraines (n pl), morainal (adj), morainic (adj), drumlin (n related)
Root
French moraine = mound of earth; possibly Savoyard dialect morena; used in geological literature from 18th c.
Etymology
From French moraine, possibly from Savoyard dialect morena ("mound of earth"); first used in geological literature in the 18th century to describe the ridges of debris observed at the margins of Alpine glaciers.
Memory Hook
Link "moraine" to "more rain" gathering more rock: picture a glacier piling up "MORE" rocky debris ("-aine") at its snout - fittingly, the root means "snout, muzzle".
How This Word Works in UPSC Writing
Rock and sediment deposited by a glacier. The types are distinguished by position and are directly examinable: lateral moraine forms along the sides of a glacier, medial moraine where two glaciers merge and their inner lateral moraines join, terminal or end moraine at the furthest extent the ice reached, and ground moraine beneath it. The hazard significance rests on the terminal moraine, because it commonly dams a lake formed by meltwater as the glacier retreats, and such a dam is built of unconsolidated debris rather than rock, so it can fail suddenly when overtopped by a surge, undercut by seepage, or struck by an avalanche or rockfall into the lake. That is a glacial lake outburst flood, and its danger lies in the combination of a very large volume released almost instantaneously into a steep valley. Assessment therefore concentrates on lakes that are growing, dammed by moraine rather than bedrock, and overlooked by unstable slopes, while mitigation works by lowering the lake through controlled channels.
Don’t Confuse It With
Lateral moraine forms along a glacier's sides, medial moraine where two glaciers merge, terminal moraine at its furthest advance and ground moraine beneath it, so the names record position rather than composition. Till is the unsorted sediment a glacier deposits, of which moraines are the landforms. An erratic is a boulder carried far from its parent rock. A glacial lake outburst flood is the sudden failure of such a dam, and the danger arises precisely because a moraine is loose debris rather than bedrock.
Hindi Meaning
हिमोढ़ (himodh); हिमनद झील विस्फोट बाढ़ for a glacial lake outburst flood.
Common Questions
- What are the four types of moraine?
- Lateral along the glacier's sides, medial where two glaciers merge, terminal at the furthest extent reached, and ground moraine beneath the ice.
- Why are moraine-dammed lakes dangerous?
- The dam is unconsolidated debris rather than rock, so it can fail suddenly if overtopped, undercut by seepage or struck by an avalanche, releasing a very large volume into a steep valley.
Seen in UPSC Question Papers
- Prelims 2024 — Disaster Management
- Prelims 2024 — Disaster Management
Real UPSC previous-year questions whose text uses “Moraine” — proof this word earns its place on your list.
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