What is a Moraine? Definition and Meaning 

For the past 16 years at Indiahikes, we have noticed many mountain terms being tossed around in conversations—sometimes correctly, but more often incorrectly. 

This is why we are creating The Trek Glossary series, where we break down one mountain term at a time. These are quick reads, but they contain accurate information that will help you understand mountain terminology. 

Today, I will dedicate my piece to explaining what a moraine is.

What is a Moraine? At What Altitude Do You Find Moraines in Himalayan Treks?

If you have traversed along the way to the Gaumukh glacier on the Gaumukh Tapovan trek, then you have already experienced a moraine section! We rarely trek on glaciers but often trek on their moraines. 

A moraine is a geological landform created by a mixture of clay, sand, rocks, and mountain debris. It can be formed when a glacier melts and leaves behind a load of this mixture (also known as glacial till). This mixture consists of rock fragments ranging from silt-sized flour to large boulders, with shapes varying from sub-angular to rounded.

We usually see glacial moraines only on very high treks, climbing above 13,000–14,000 ft, where glaciers are seen.

How is a moraine formed?

The main reason behind the formation of moraines is the movement and melting of glaciers. The process is dynamic, evolving with the glacier's movement, size, and surrounding terrain.

Additionally, moraine formations are not static. They keep evolving due to three factors, mainly the seasonal melting of glaciers, climate change, and natural disasters (e.g., landslides and earthquakes). These three factors alter the composition and position of moraines.

I will break down the formation of moraine in three stages.

A three-stage process of Moraine formation

Stage 1: Glacial Movement

The process starts with glaciers acting as natural bulldozers, moving slowly but powerfully over the landscape. So, what happens as they advance? Glaciers move against mountains and valleys, grinding rocks into fragments of different sizes. The glacier carries these fragments, ranging from massive boulders to fine silt.

Stage 2: Melting and Deposition

When a glacier melts or retreats, the debris it carries is deposited as unsorted material. It ranges from large boulders to smaller rocks and fine particles. Another kind of deposition could be irregular or ridged terrain. The shape of a moraine depends on the glacier’s path.

Stage 3: Compaction

Typically, the till deposited is loose in composition. Over time, it compacts and takes on a more solid formation as it settles.

What are the types of moraines? 

Moraines are categorised into five types based on their position relative to the glacier. Each type of moraine gives an idea of its interaction with the surrounding environment: 

1. What is Lateral Moraine?

A lateral moraine is a ridge that is formed along the sides of glaciers. It is formed as glaciers scrape off rock, soil, and debris from the valley walls. These ridges provide a clear picture of how the glacier sculpts the landscape as it advances.

2. What is Medial Moraine?

When two glaciers merge, debris from their lateral moraines combines to form a medial moraine. This material, consisting of rock and debris, accumulates in the centre of the glacier formed by this collision. And if this glacier melts, the remains form a long ridge in the middle of a valley.

3. What is Terminal Moraine?

This moraine gives us valuable insights into the furthest extent of a glacier's historical reach. It marks the maximum point reached before the glacier begins to retreat. As the glacier melts, it leaves behind a ridge of deposited material.

4. What is Ground Moraine?

In contrast to more prominent ridges, the ground moraine consists of thin layers of debris. These formations occur directly underneath a glacier by tiny streams. Typically, they create rolling hills or irregular terrain, which contrasts with the more defined ridges of terminal moraines.

According to National Geographic: “Ground moraines are the most common type of moraine and can be found on every continent”.

5. What is Supraglacial Moraine? 

Supraglacial Moraine occurs on the glacier's surface. Lateral and medial moraines can be supraglacial moraines. It is formed from debris, such as rocks and material from avalanches, that accumulates on top of the ice. 

For those studying glacial formations, Gaumukh Tapovan is an excellent site to observe supraglacial moraines in detail.

Treks where you’ll navigate through moraine

Below I will list the 10 most popular treks in the Indian Himalayas that allow you to navigate through a moraine section. Some of them are really challenging while others are comparatively easier. 

• Gaumukh Tapovan: Moraine sections are significant along the way to the Gaumukh Glacier, especially between Tapovan and the glacier itself. Lateral and terminal moraines dominate this route.

• Nafran Valley: Created from the Kolahoi glacier, lateral moraines can be seen often lining the trail. These are observed along the trail from Harnag to Harbhagwan Lake.

• Pin Bhabha Pass: Noticeable lateral moraine sections are present between the Phutsirang campsite and Bwalder. 

• Warwan Valley: The trail from Dinora to Kalapari includes ground moraine and some medial sections. The moraine is created because of the Bracken glacier.

• Everest Base Camp (EBC): The route to EBC showcases visible medial and terminal moraines starting at Labouche, close to Gokyo Lake and Chola Pass. Views of moraines can also be encountered at Kalapathar.

• Kedartal Trek: Expect to see recessional and lateral moraine landscapes from Gangotri onwards. 

• Hampta Pass: Ground and lateral moraines emerge near Balu ka Gera to Shea Goru.

• Kashmir Great Lakes (KGL):  Lateral moraines & boulders predominantly surround the lakes and passes on this trek.

• Miyar Valley: Prominent ground and terminal moraine sections are evident on the final day as you approach the end of the valley.

• Ala Kul Lake Trek: The Ala Kul Lake trek features three types of moraines: lateral moraines located along the valley sides, a terminal moraine near Ala-Kul Lake, and some sections of medial moraines as well (which are less prominent as compared to lateral and terminal moraines)

Techniques and essential gear to trek through moraine

Treks with moraine sections pose unique challenges due to the unstable terrain formed by glacial deposits. Moraine requires not only physical preparation but also technical gear. 

Starting with,

Essential Gear for Moraine Treks

Moraines should be navigated with gears and shouldn’t be 

1. Full-length Trek Pants

Last and most importantly, opting for full-length trekking pants is a wise decision. Choose a pair that offers resistance to abrasions, ensuring they can withstand rugged terrain (especially moraines)

2. Gaiters

Gaiters are a must for any trek involving moraine. These protective covers fit over your shoes and lower legs, preventing loose rocks, silt, and debris from getting inside. Without gaiters, the constant entry of these particles leads to discomfort, blisters, or even injuries that might halt your trek.

3. Trekking Poles

Our expert trek leaders advise: Trekking poles are not optional; they’re essential. Think of them as your extra set of limbs on moraine. When used correctly, poles offer unmatched stability and reduce the impact on your knees. Always remember to keep them close to your body for control and efficiency. Many trekkers make the mistake of planting poles too far ahead, leading to instability as the loose terrain shifts beneath them.

4. High-Quality, Grip-Focused Shoes

Ordinary trekking shoes won't cut it on moraine. Invest in a pair of high-traction, durable shoes that can handle sharp rocks and slippery ground. Look for soles with deep lugs for maximum grip and support. 

What shoes are perfect to navigate through moraine?

Many people have been asking this one question for quite some time. I will recommend what you should look for if you are going on a trek that involves covering a moraine section. 

• High-ankle trekking shoes are a necessity. These help prevent ankle twists and offer stability on uneven surfaces.
• Ensure the soles have deep grooves for a reliable grip, as worn-out soles increase the risk of slipping.

Techniques to Follow While Ascending Moraine

• Use Your Toes for Grip:

When ascending a moraine section of a trek, always rely on the ball of your foot (toes) rather than placing your full foot flat on the ground. Flat footing reduces your chances of finding traction, causing you to slip. Your toes offer better contact and control on small, uneven rocks.

• Step with Purpose:

All the trek leaders I spoke with shared one important piece of advice: make each step deliberate and controlled. Avoid rushing, as the loose terrain tends to act like a rollerblade—you push forward only to slide back. Progress slowly, and avoid standing in one place for extended periods, as this not only tires your legs but also risks destabilization.

• Pole Placement:

Anchor the poles securely in the ground while keeping them close to your body for better stability. Gradually position them outward so they create a stable triangle with your feet positioned beneath you. This technique effectively distributes your weight across the poles and your legs, minimizing strain and enhancing balance as you navigate through the moriane section.

• Mental Readiness:

Trekkers often hesitate on steep ascents, fearing a fall. This fear can lead to stagnation, which increases the likelihood of losing balance. Keep a steady rhythm, focus on your next step, and trust your equipment.

Techniques to Follow While Descending Moraine

• Diagonal and Sidewalk Technique:

NEVER descend the moraine directly; this increases your speed uncontrollably, leading to falls. Instead, adopt a diagonal or sideways stance. Turning your body to face sideways minimizes the risk of slipping while giving you more control over your movement. Lead with your stronger leg to maintain stability.

• Quick Movement:

While counterintuitive, a brisk descent is safer. Staying in one spot on the moraine for too long risks sinking into the unstable ground, making it harder to regain momentum. Do not rush, move confidently while maintaining control.

• Using Trekking Poles:

Place the poles slightly ahead of you, near your stronger leg. Ensure they are firmly planted before taking the next step. Poles closer to your body offer better leverage, effectively acting as an anchor in the loose terrain.

• Foot Positioning:

This is a technique that every trekker should follow, regardless of their level of experience. What you do is bend your knees slightly to absorb impact and prevent strain on your joints. Lean slightly back for balance, ensuring your weight is distributed evenly. Avoid locking your knees, as this restricts flexibility and increases the risk of falls.

Our observations of moraine and climate change

Moraines are a significant feature of the landscape and can be used to understand the glacial activity and the impact of climate change in the region. 

Over the last 16 years, we have witnessed dramatic landscape changes across treks like Gaumukh Tapovan. In 2022, the Gangotri Glacier revealed a load of debris. It is a stark reminder of global warming’s impact. 

These shifts underline the need to connect our trekking experiences to broader discussions about climate and geology.

Did you know? 

Chorabari Tal (also known as Gandhi Sarovar) above Kedarnath temple is a moraine-dammed lake. In 2013, because of heavy rainfall and melting glaciers, there were glacial lake outburst floods at the lake, resulting in the infamous flash flood in Kedarnath.

Frequently Asked Questions

Q1: What is the difference between scree and moraine?
The primary difference between scree and moraine lies in how they are formed. Scree refers to loose rock fragments and debris that collect at the base of slopes whereas moraine is a formation of landform created by glacial till (clay, sand, rocks, and mountain debris). Unlike moraine, scree isn’t necessarily formed by glaciers but can appear in various mountain terrains. You will find a few scree sections on treks like Pin Bhaba Pass, Ala Kul, Warwan Valley and more. Trekking on scree is very challenging, because, for every two steps you take, you move a step back. 

In Conclusion

That is all you need to know about moraine. If you have any questions you would like to ask, drop them in the comments section. I'd like to know if you have covered any moraine sections and which treks they were part of. 

Please let me know in the comments section if you want me to cover specific trek terms. I will write about them in my upcoming posts.