The Himalayan Ranges — Part II
Regional Himalayan ranges from Kashmir to Arunachal: Punjab, Kumaon, Nepal, Sikkim, and Assam Himalayas, plus Trans-Himalayan features.
Important Valleys of the Himalayas
Himalayan valleys are formed by the interplay of tectonic activity, river erosion, and glacial action. They are of immense geographic, economic, and strategic significance.
Classification of Himalayan Valleys
- Strike Valley (Longitudinal Valley): Runs parallel to the mountain ridges; formed in synclines.
- Transverse Valley: Formed by rivers cutting across the mountain ranges (antecedent rivers).
- Dun/Doon Valleys: Structural valleys between Shiwaliks and Lesser Himalayas; flat-floored.
Major Valleys
Kashmir Valley
- Located between the Greater Himalayas (north) and the Pir Panjal Range (south).
- Average elevation: 1,585 m above mean sea level.
- Shape: Synclinal basin; bowl-shaped, surrounded by ranges.
- Sediments: Alluvial, lacustrine (lake), fluvial, and glacial deposits.
- The Jhelum River meanders through the valley, draining through a gorge cut in the Pir Panjal.
- Vulnerability: Due to limited drainage outlets, Kashmir Valley is highly susceptible to flooding.
Karewas:
- Thick deposits of glacial clay, lacustrine deposits, and moraines found in Kashmir Valley and Bhadarwah Valley (Jammu Division).
- Appear as flat-topped mounds bordering the valley on all sides.
- Formed when the entire valley was submerged in water during the Pleistocene Period (~1 million years ago); drained when the Baramullah Gorge was created by endogenic forces.
- Karewa thickness: ~1,400 m.
- Economic significance: Cultivation of Zafran (Kashmir saffron) — a GI-tagged product; also almonds, walnuts, apples.
Zabarwan Range:
- Small range between Sind River Valley and Lidder River Valley in the north-central part of Kashmir Valley.
- Overlooks Dal Lake and the Mughal Gardens of Srinagar.
- Houses the Indira Gandhi Memorial Tulip Garden — largest tulip garden in Asia.
- Contains Dachigam National Park — home to the critically endangered Kashmir Stag (Hangul).
Kangra Valley (Himachal Pradesh)
- A strike valley between the Dhauladhar Range (north) and Shivalik Hills (south).
- Extends from the foot of Dhauladhar to the Beas River.
- Famous for: Kangra Tea — registered Geographical Indication (GI) product; grown in Dharamshala, Palampur, and Baijnath.
Kulu Valley (Himachal Pradesh)
- A transverse valley formed by the Beas River between Manali and Larji.
- Famous for: tourism, apple orchards, Kullu Dussehra festival.
Strike Valley vs Transverse Valley: A strike valley runs parallel to the ridges (along the strike direction of rock strata). A transverse valley cuts across rock strata — formed by antecedent rivers that predate the mountain uplift.
Doon Valley (Uttarakhand)
- Lies between the Lesser Himalayas and the Shiwaliks.
- Contains Dehradun — capital of Uttarakhand.
- Formed by the downcutting of the Song River and Asan River.
- Other notable duns: Kotlidun, Patlidun, Chandigarh-Ambala area.
Other Notable Valleys
| Valley | Location | River/Feature |
|---|---|---|
| Bhagirathi Valley | Uttarakhand | Near Gangotri glacier; source of Ganga |
| Mandakini Valley | Uttarakhand | Near Kedarnath |
| Kathmandu Valley | Nepal | Between Greater and Lesser Himalayas |
| Pokhara Valley | Nepal | Second largest valley of Nepal |
Note: Both Kathmandu and Pokhara valleys are highly vulnerable to earthquakes due to liquefaction potential of loosely deposited clayey alluvium.
Snow and Glaciers
The Snowline
The snowline is the lowest level of perpetual snow on a mountain. Its elevation varies based on:
- Latitude — higher latitude = lower snowline
- Precipitation — more precipitation on south-facing slopes = lower snowline
- Aspect — south-facing slopes receive more solar radiation = higher snowline
| Region | Snowline Elevation |
|---|---|
| Eastern Himalayas / Kumaon | ~3,500 m |
| Punjab Himalayas (Western) | ~2,500 m |
| Greater Himalayas (south slopes) | Lower than north slopes (more precipitation) |
The western Himalayas receive less total precipitation (mainly from Western Disturbances as snowfall); the eastern Himalayas receive more precipitation from the SW Monsoon. This, not latitude alone, explains the difference in snowline elevation.
Major Glaciers of the Himalayas
A glacier is a large body of crystalline ice, snow, rock, and sediment that moves slowly downslope under the influence of gravity. Formed by the perennial accumulation and compaction of snow over decades.
Total count: ISRO study identified 34,919 glaciers spread over 75,779 sq km in the Indus, Ganga, and Brahmaputra basins (including Trans-Himalayas and Karakoram).
Glaciers of the Karakoram Range
The maximum development of glaciers outside the polar regions occurs in the Karakoram Range.
| Glacier | Length | River Fed | Notes |
|---|---|---|---|
| Siachen | 75 km | Nubra River → Shyok → Indus | Largest glacier outside polar regions; world's highest battleground (−50°C) |
| Hispar | 62 km | Hispar River → Hunza → Indus | Converges with Biafo at Hispar La Pass (5,128 m) |
| Biafo | 67 km | Biafo River → Shigar → Indus | Connects with Hispar via Snow Lake |
| Baltoro | 57 km | Braldo River → Shigar → Indus | Near K2; one of world's most famous glacier treks |
| K2/Godwin-Austen | — | Near K2 peak | In Gilgit-Baltistan (PoJK — Indian territory under illegal Pakistani occupation) |
| Khurdopin | — | Shimshal River → Hunza | — |
| Rimo | — | Shyok River | Near Siachen |
| Chong Kumdan | — | Shyok River | Lower Karakoram slopes |
Siachen Glacier is a piedmont glacier — formed when valley glaciers spread out into a flat area. It originates at Indira Col West on the Indira Ridge.
Fedchenko Glacier (Pamirs, Tajikistan) = second largest glacier outside polar regions (~74 km); Hispar = third largest.
Glaciers of Jammu & Kashmir
| Glacier | Location | River Fed | Notes |
|---|---|---|---|
| Kolahoi | Near Pahalgam | Lidder River → Jhelum | Highest and largest glacier in Kashmir |
| Thajiwas | Ganderbal | — | — |
| Harmukh | Ganderbal | Gangabal Lake (Haramukh Ganga) | — |
| Machoi | Zanskar Himalayas, Drass (Ladakh) | Sind River (→ Jhelum) + Drass River (→ Suru) | Near Zoji La Pass |
Glaciers of Ladakh
Drang Drung Glacier:
- Near Pensi La Pass in Zanskar Himalayas.
- Source of Doda River — the largest tributary of the Zanskar River.
Shafat Glacier: Feeds the Suru River (tributary of Indus).
Pensilungpa: Northwest corner of Zanskar Valley; also feeds Suru.
Glaciers of Himachal Pradesh
| Glacier | Location | River Fed | Notes |
|---|---|---|---|
| Bara Shigri | Lahaul region | Chandra River → Chandrabhaga (Chenab) | Largest glacier in HP |
| Chhota Shigri | Lahaul-Spiti, near Rohtang Pass | Chandra River | — |
| Beas Kund | Pir Panjal, near Rohtang Pass | Beas River (source) | Glacial lake |
| Suraj Tal (Tso Kamtsi) | Near Baralacha Pass, Lahaul-Spiti | Bhaga River (source) | Glacial lake |
| Bhadal Glacier | Pir Panjal, Kangra district | Bhadal Nallah → (with Rai Nallah + Tantgari Nallah) → Ravi River | — |
In HP, glaciers are locally called shigri. Old name of Chenab = Askini.
Glaciers of Uttarakhand
| Glacier | Location | River Fed | Notes |
|---|---|---|---|
| Gangotri | Uttarkashi, Garhwal Himalaya | Bhagirathi River (source of Ganga) | One of the largest Himalayan glaciers; retreating rapidly |
| Chorabari (Kedarnath) | Near Kedarnath | Mandakini River | Site of 2013 Kedarnath disaster |
| Satopanth | Chamoli district | Alaknanda River | — |
| Milam | Pithoragarh, Kumaon | Gori Ganga River | — |
| Pindari | Bageshwar, Kumaon | Pindar River | Popular trekking glacier |
| Poting | — | Gori Ganga River | — |
Glaciers of Sikkim
| Glacier | Notes |
|---|---|
| Zemu | Largest glacier in eastern Himalayas; near Kangchenjunga |
| Lonak | Near South Lhonak Lake — site of October 2023 GLOF |
The Purvanchal (Eastern Hills)
- A chain of hills in Northeast India, forming the eastern flank of the Himalayan arc.
- These are the continuation of the Himalayan system but geologically distinct.
- Orientation: Generally north-south in Nagaland, Manipur, Mizoram; curves eastward in Arunachal.
Major Hill Ranges
| Range | States | Highest Peak | Notes |
|---|---|---|---|
| Patkai Hills | Arunachal/Nagaland-Myanmar border | ~3,000 m | Forms India-Myanmar boundary |
| Naga Hills | Nagaland | Saramati (3,841 m) | Highest in Nagaland |
| Manipur Hills | Manipur | — | Surrounds Imphal Valley |
| Mizo Hills (Lushai Hills) | Mizoram | Phawngpui / Blue Mountain (2,157 m) | Highest in Mizoram |
| Tripura Hills | Tripura | Betlingchhip (976 m) | Low elevation |
| Garo Hills | Meghalaya | Nokrek (1,412 m) | Western Meghalaya |
| Khasi Hills | Meghalaya | Shillong Peak (1,961 m) | Home of Cherrapunji/Mawsynram |
| Jaintia Hills | Meghalaya | — | Eastern Meghalaya |
| Barail Range | Assam-Nagaland border | — | Separates Brahmaputra and Barak basins |
| Mikir Hills (Karbi Anglong) | Assam | — | Isolated plateau in Assam |
Shillong Plateau (Meghalaya Plateau): A part of the ancient Gondwana landmass — geologically it is a detached part of the Peninsular Plateau, not part of the Himalayas. Also called the "Meghalaya Plateau." The Garo-Rajmahal gap separates it from the main peninsula.
Himalayan Rivers — Classification and Key Concepts
Antecedent Rivers
- Himalayan rivers (Indus, Ganga tributaries, Brahmaputra) are antecedent — they predate the Himalayas.
- They maintained their original courses as the mountains rose beneath them.
- This explains why they cut deep gorges through the ranges rather than being diverted.
- Evidence: Indus Gorge (near Nanga Parbat), Brahmaputra Gorge (near Namcha Barwa) — among the world's deepest gorges.
River Capture / Piracy
- Due to the asymmetrical structure of the Himalayas (steeper south slopes), the river systems on the south have greater erosive power.
- This has led to river capture (piracy) — southward-flowing rivers capturing the upper courses of rivers flowing northward.
Gorges vs. Valleys
| Feature | Young Mountains | Old Mountains |
|---|---|---|
| Valley shape | V-shaped / gorge | Broad, U-shaped |
| Gradient | Steep | Gentle |
| Erosion | Active downward cutting | Lateral erosion dominant |
| Waterfalls | Common | Rare |
Glacial Lake Outburst Flood (GLOF) — Concept and India's Vulnerability
What is a GLOF?
A GLOF occurs when water retained by a glacial lake is suddenly released due to:
- Moraine dam failure (dam made of glacial debris)
- Displacement wave from landslide/ice avalanche into lake
- Permafrost degradation (thawing of frozen ground supporting moraines)
- Earthquake triggering
India's GLOF Vulnerability
- ISRO identified 676 glacial lakes in Indian Himalayan basins; 601 have expanded more than twice since the baseline period.
- States at risk: Uttarakhand, Himachal Pradesh, Sikkim, Arunachal Pradesh.
- Climate change is accelerating glacier melt → more and larger glacial lakes → greater GLOF risk.
Kedarnath Disaster (June 2013)
- Chorabari Glacier lake burst due to extreme rainfall.
- One of India's worst natural disasters in the Himalayas: ~5,700 people dead/missing.
- Triggered massive flash floods in Mandakini and Alaknanda river systems.
Sikkim GLOF (October 2023) — Detailed Analysis
- Lake: South Lhonak Lake, North Sikkim (~5,200 m elevation).
- Trigger: Permafrost landslide (~14.7 million m³) → 20 m displacement wave → moraine breach.
- Discharge: ~50 million m³ of water released; peak flow 48,500 m³/s.
- Trail: 385 km along Teesta River to Bangladesh.
- Deaths: ~92 confirmed, 74+ missing.
- Infrastructure: Teesta III Dam destroyed; 31 bridges lost; 25,900+ buildings damaged.
- Climate link: ICIMOD confirmed climate change accelerated South Lhonak Lake expansion.
UPSC Corner
Key One-Liners for Prelims
- Bara Shigri = largest glacier in HP; feeds Chenab (via Chandra River)
- Gangotri Glacier = source of Bhagirathi = source of Ganga; in Uttarkashi
- Zemu Glacier = largest glacier in eastern Himalayas; near Kangchenjunga
- Siachen Glacier = largest outside polar regions = 75 km = world's highest battlefield
- Karewas = deposits of glacial + lacustrine material in Kashmir = ideal for saffron cultivation
- Kangra Tea = GI-tagged product from Kangra Valley, HP
- Dachigam National Park = Zabarwan Range = Kashmir Stag (Hangul) = Critically Endangered
- Shillong Plateau = geologically part of Peninsular (Gondwana) plateau, NOT Himalayas
- Antecedent rivers = Himalayan rivers; predate the mountains
- GLOF = Glacial Lake Outburst Flood; 601 of 676 Indian glacial lakes have expanded >2x (ISRO 2024)
- Kedarnath 2013 = Chorabari Glacier lake burst; 5,700+ deaths
- Sikkim GLOF 2023 = South Lhonak Lake; 92 deaths; Teesta III dam destroyed
Mains GS1 Questions
- "What are glacial lake outburst floods (GLOFs)? Analyze India's vulnerability and suggest mitigation measures."
- "Discuss the significance of the Purvanchal hills in the context of India's northeastern geography and security."
- "What are karewas? Discuss their formation and economic significance."
- "Explain the concept of antecedent drainage with examples from the Himalayas."
- "How is climate change altering the cryosphere of the Himalayas? Discuss implications for water security."
MCQ Trap Awareness
- Trap: "Gangotri is the source of the Ganga" → Technically incorrect — Gangotri is the source of the Bhagirathi, which joins the Alaknanda at Devprayag to form the Ganga.
- Trap: "Zemu glacier is in Uttarakhand" → Incorrect — it is in Sikkim (near Kangchenjunga).
- Trap: "Siachen is in the Himalayas" → The glacier is under Indian administration and is Indian territory; it lies in the Karakoram range, not the Greater Himalayas.
- Trap: "Shillong Plateau is part of the Himalayas" → Incorrect — it is geologically a detached piece of the Peninsular Plateau (Gondwana).
- Trap: "Beas river originates from Rohtang Pass" → More precisely it originates from Beas Kund, a glacial lake near Rohtang Pass.
The Kashmir Valley lies between the Greater Himalayas (north) and the Pir Panjal Range (south) at an average elevation of 1,585 m. It is a synclinal basin drained by the Jhelum River, which exits through a gorge cut in the Pir Panjal — making the valley highly susceptible to flooding.
Karewas are thick deposits (~1,400 m) of glacial clay, lacustrine sediments, and moraines found in the Kashmir Valley and Bhadarwah Valley. They formed when the valley was submerged in a Pleistocene lake (~1 million years ago), which drained when the Baramullah Gorge opened. Karewas are uniquely suited for cultivating Zafran (Kashmir saffron), a GI-tagged product.
The Zabarwan Range overlooks Dal Lake and Srinagar's Mughal Gardens. It houses Dachigam National Park, the habitat of the critically endangered Kashmir Stag (Hangul), and the Indira Gandhi Memorial Tulip Garden — the largest tulip garden in Asia.
The Kangra Valley (Himachal Pradesh) is a strike valley between the Dhauladhar Range (north) and Shivalik Hills (south), famous for Kangra Tea — a Geographical Indication (GI) tagged product grown in Dharamshala, Palampur, and Baijnath.
The Shillong Plateau (Meghalaya Plateau) is geologically a detached fragment of the Peninsular (Gondwana) Plateau — NOT part of the Himalayas. It is separated from the main Peninsular plateau by the Garo-Rajmahal gap. Cherrapunji and Mawsynram, among the wettest places on Earth, are located here.
Himalayan rivers (Indus, Ganga tributaries, Brahmaputra) are antecedent rivers — they predate the Himalayas. They maintained their original courses as the mountains rose beneath them, cutting deep gorges. The Indus Gorge near Nanga Parbat and the Brahmaputra Gorge near Namcha Barwa are among the world's deepest.
Siachen Glacier (75–76 km, Karakoram) is the largest glacier outside the polar regions and the world's highest battlefield. It originates at Indira Col West on the Indira Ridge and feeds the Nubra River, which joins the Shyok River, which then joins the Indus River.
Gangotri Glacier in Uttarkashi district, Uttarakhand is the source of the Bhagirathi River (a headstream of the Ganga). It is one of the largest glaciers in the Indian Himalayas (outside Karakoram) and is retreating rapidly. Note: the Ganga is formally formed at Devprayag where Bhagirathi meets Alaknanda.
Zemu Glacier (North Sikkim) is the largest glacier in the Eastern Himalayas, located near Kangchenjunga. Its meltwater contributes to the Teesta River and played a role in the 2023 South Lhonak GLOF disaster.
Bara Shigri is the largest glacier in Himachal Pradesh, located in the Lahaul region. It feeds the Chandra River, which combines with the Bhaga River to form the Chandrabhaga (Chenab). In Himachal Pradesh, glaciers are locally called 'shigri'.
ISRO identified 34,919 glaciers covering 75,779 sq km across the Indus, Ganga, and Brahmaputra basins (including Trans-Himalayas and Karakoram). Of 676 glacial lakes monitored, 601 have expanded more than twice since the baseline, indicating widespread glacial retreat.
A GLOF (Glacial Lake Outburst Flood) occurs when a glacial lake dam (typically moraine or ice) suddenly breaches, releasing millions of cubic metres of water as a destructive debris flow. Triggers include ice/rock avalanches into the lake, permafrost thaw, seepage through the moraine dam, and earthquakes.
The Kedarnath disaster (June 2013) was caused by the burst of the Chorabari glacial lake following extreme rainfall, triggering massive floods in the Mandakini and Alaknanda rivers. Approximately 5,700 people died or went missing — making it India's worst Himalayan disaster in decades.
The Sikkim GLOF (October 2023) at South Lhonak Lake involved a ~14.7 million m³ permafrost landslide generating a 20 m wave. The resulting flood released ~50 million m³ of water (peak flow 48,500 m³/s), destroyed the Teesta III Hydropower Dam, 31 bridges, and killed ~92 people. The flood travelled 385 km along the Teesta to Bangladesh.
Beas River originates from Beas Kund, a glacial lake near Rohtang Pass (Himachal Pradesh). Suraj Tal (Tso Kamtsi), near Baralacha Pass in Lahaul-Spiti, is the source of the Bhaga River. Bhaga and Chandra rivers join to form the Chandrabhaga, known as Chenab in the plains (old name: Askini).
Related Chapters
The Himalayan Ranges — Part I
Origin, structure, and division of the Himalayan system — Himadri, Himachal, Shiwaliks — with passes, longitudinal valleys, and regional ranges.
Glaciers and the Cryosphere of India
Himalayan glaciers and the Third Pole — glacier inventory, Siachen/Gangotri/Zemu, retreat causes, Karakoram Anomaly, GLOF risk (Sikkim 2023), permafrost, NMSHE, and ICIMOD.
Deserts of India — Hot Desert (Thar) and Cold Deserts (Ladakh, Spiti, Lahaul)
The Thar (Great Indian Desert) — NCERT's 4th physiographic division: dune types, saline lakes, Luni River, Great Indian Bustard, Indira Gandhi Canal, and traditional water harvesting.
Northeast India — Geography, Ecology and Strategic Significance