198,000 glaciers are present in the world which cover about 726,000 sq. km of the surface of the Earth. Over the centuries lots of glaciers have melted due to global warming. But have you ever thought about how does a glacier remain stationary? Do they float and if they can move, why do glaciers stop moving? Glaciers are huge and to move such huge masses of ice would take a strong current. But can glaciers move without melting? Let’s find out.
1. What are Glaciers?
Fallen snow over years that has compressed into a large thick mass of ice is known as glaciers. Initially, they are not ice but snow that has fallen over the place and remained in the same place for years. This long duration turned it into ice. (See What is the Largest Glacier in the World?)
2. What is an Ice Cap and Ice Sheet?
A dome-shaped glacier that can flow in all directions is known as the ice cap. For example, Ellesmere Island in the Canadian Arctic. A dome-shaped glacier covering 50,000 square kilometers is known as an ice sheet. For example, Antarctica and Greenland. (See Why Ice floats on Water?)
3. How are they formed?
When snow remains in the same place for over a year, the snow starts turning into ice. Every year a new layer of ice is formed that buries the previous layers and compresses them. This force applied from above re-crystallizes the ice below, making the crystals smaller. With more addition of layers, the grains get bigger and the air pockets get smaller. This made the ice more compact, which increases its density. (See What are Geologic Features?)
4. What is Firn?
So, how does a glacier remain stationary? Before that let me tell you about firn. This is the stage where snow reaches after a year of compression. It is known as the intermediate stage of the glacier when it is between snow and ice. At this stage, the glacier is about 2/3rd as dense as water. As time passes by, the air pockets get smaller, and smaller than several inches of layers get added to the glacier. (See When does Snow stick to the Ground?)
5. Where to find Glaciers?
Glaciers can be formed in any region where there is enough snowfall along with other geographical conditions. The most common region of their existence is above the snow line. It is the region that receives high snowfall during winters and cool summer temperatures, just the way it is in polar regions and mountainous regions. This condition enables the snow to stay for years long. Snow lines are at different altitudes in different regions. Therefore, the existence of snowfall depends largely on the amount of snowfall a glacier is receiving. (See Why can’t We go to Antarctica?)
6. Why are Glaciers moving?
Glaciers begin to move as a result of their own weight and the force of gravity on their mass. This happens because ice gets reshaped due to its weight, causing it to flow slowly in the direction of the wind or the current. The speed of glaciers seems slower below the water than in the above portion. Glaciers can flow spread into the sea, flow into the plains, and even flow down the mountain valleys. (See What States don’t get Snow?)
7. What is Basal Sliding?
Before getting to how does a glacier remain stationary, first let’s discuss how it slides. A glacier located over the thin ice layer seems to move with the thin layer of water at its base due to melting. This type of movement in glaciers is termed basal sliding. The melting occurs due to the pressure of the ice above it or the water getting into it through the cracks at the base. The glaciers present on the steep slopes are thin and cold. Basal sliding takes place in these glaciers. (See What is the Largest Island in Asia?)
8. Can Glaciers move without Melting?
Yes, most of the glaciers are moving without melting. But the reason behind it is the gravitational force and its mass.
9. How Fast can a Glacier flow?
Their speed can be pretty fast as seen in the Jakobshavn Glacier which moves at a speed of 30 meters per day (98 feet per day). However, a slow-moving glacier covers up to 0.5 meters per year (20 inches per year). However, the average speed of the moving glaciers is 25 cm per day (9.8 inches per day). (See 16 Snowing in the Mountains Facts)
10. Which are the Fastest and Slowest Glaciers?
Beginning with the fastest we will go to the slowest as follows:
- Jakobshavn Isbrae (Jakobshavn Glacier) is a Greenland ice sheet that can move 126,00 meters per year
- Pine Island Glacier from West Antarctica covers 2075 meters per year
- Fox Glaciers in New Zealand cover the least distance among all, 182 meters per year.
These are interesting facts other than how does a glacier remain stationary. Must read what is the difference between hills and mountains?
11. Do Glaciers melt while flowing?
A flowing glacier moves in the same way as things move on a conveyor belt. They are moving forward and towards a downward slope. All these deform the retreating or flowing glacier. Therefore, a flowing glacier always moves down the hill and never uphill. And in this process of deformation, the flowing glacier is melting faster than it is flowing. (See What is the Difference between Tropical and Polar Regions?)
12. Why do Glaciers stop moving?
Glaciers may stop moving when they are not being deformed at the base due to their own mass and gravitational force. Also, when the glaciers are melting and evaporating due to high temperatures and wind they tend to stop and soon melt away. Read the next segment if you want to know how does a glacier remain stationary and what are the conditions. (See What does the Thermometer and Snowflake mean on Weather App?)
13. How does a Glacier remain Stationary?
Glaciers grow in size and mass as snow accumulates over them year after year for centuries. However, the weight and size of a glacier have nothing to do with the glacier being stationary. Melting and accumulation are the key components here. A glacier remains stationary when the amount of ice melting at the base is equal to the amount of snow getting accumulated above it. (See Does it Snow in Australia?)
14. Are Moving Glaciers disrupting People?
Remembering the Titanic tragedy, we can say that ships are sure in danger from these glaciers.
Well, apart from that, glaciers are quite a helpful resource to humans. Many rivers are snow fed but during summers when rainfall is less and evaporation is high, the melted glaciers form a significant part of the rivers. They are a steady source of generating hydroelectricity. Countries like Central Europe, Canada, Norway, New Zealand, and South America use dams to use glacial melted water to generate hydroelectric power. Also, check out How Many Blocks make an Igloo?
15. Is the Moving Glacier reforming Land?
Glaciers have their masses more beneath the water than they are visible on the surface. Therefore, as they flow and move, they are reshaping landscapes over centuries. The ice erodes the land and takes away the debris and broken rocks with it. This forms a glacial landform. (See What is a Cold Front?)
16. What is Glacial Erosion?
Glacial valleys and landforms are melted or broken due to environmental impact or other conditions. All this leads to glacial erosion, which is the flowing of a large broken glacier mass. There are 3 types of glacial erosion:
- Aretes: When the ridges of two glaciers are eroded, narrow and jagged ridges are formed at the back of the glaciers. It is at the point where both glaciers meet each other.
- Cirques: A glacier is a bowl-shaped depression or valley with steep faces. These faces are facing upwards and look similar to tilted bowls. This happens when the glacier melts away or breaks off from the mountainside.
- Horns: This is the pointed mountain peak with sharp ridges. When the glaciers erode a mountain leaving nothing but the rocks of the mountain, then the leftover peak is known as the horn.
So, now you know the logic behind how does a glacier remain stationary. You can ask others why do glaciers stop moving. Confuse your friends and family members by asking how can glaciers move without melting. (Also read What are Factors affecting Soil Weathering?)