Crevasse facts for kids

A deep crack, called a crevasse, in the Easton Glacier on Mount Baker in Washington.

A crevasse is a deep crack or split found in a large sheet of ice, like an ice sheet or a glacier. Think of it like a crack that forms in a rock, but this one is in ice! Crevasses form because glaciers are always moving. As different parts of the ice move at different speeds, it creates stress, causing the ice to crack.

These cracks often have walls that go straight down or are nearly vertical. Sometimes, these walls can melt and create interesting ice shapes. These shapes might look like ice towers called seracs, or even natural ice arches.

What is a Crevasse?

Crevasses are basically giant cracks in glaciers. They can be very deep and wide. Glaciers are huge rivers of ice that slowly flow over land. As they move, the ice stretches and pulls apart, leading to these cracks. Imagine bending a thick piece of plastic; it might crack if you bend it too much. Ice does something similar.

How Crevasses Form

Crevasses form because of the way glaciers move. A glacier doesn't move like one solid block. Different parts of it can move at different speeds. For example, the middle of a glacier usually moves faster than the edges. Also, when a glacier flows over uneven ground, like a bump or a steep slope, the ice can stretch and break.

This stretching and pulling creates what scientists call "shear stress." This stress causes the ice to fracture, forming crevasses. They can be found in many places on a glacier, especially where the ice speeds up or goes over a change in the land's shape.

Types of Crevasses

Crevasses can look different depending on how they form and where they are on the glacier. Here are a few common types:

• Transverse crevasses: These cracks form across the glacier, usually when the ice speeds up or goes over a bump. They look like lines going from one side of the glacier to the other.
• Longitudinal crevasses: These cracks run parallel to the direction the glacier is moving. They often form when the glacier spreads out sideways, like when it enters a wider valley.
• Marginal crevasses: These are found near the edges of a glacier. They often form at an angle because the ice at the edges moves slower than the ice in the middle.
• Bergschrund: This is a special type of crevasse that forms at the very top of a glacier. It separates the moving glacier ice from the ice that is stuck to the mountain.

Staying Safe Around Crevasses

Crevasses can be very dangerous for people exploring glaciers. They can be hidden by fresh snow, making them hard to see. This is why people who travel on glaciers, like mountaineers, use special safety equipment. They often tie themselves together with ropes so that if one person falls into a crevasse, the others can help pull them out. They also use tools to check for hidden cracks.

It's important to always be careful and aware of your surroundings when near glaciers. Always go with experienced guides if you are exploring these icy places.

Images for kids

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  Transverse crevasses in Chugach State Park, Alaska.

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  A crevasse in Tangra Mountains, Antarctica.

See also

In Spanish: Crevasse para niños