Crevasses are one of the most dramatic and dangerous features found in glacial environments. Often hidden beneath layers of snow or disguised by shadows, these deep cracks in glacial ice are capable of swallowing entire climbers, vehicles, or equipment. Their depth varies greatly, but even shallow ones can be hazardous. Understanding how deep a crevasse can be and the factors that influence its depth is crucial for mountaineers, scientists, and anyone interested in glaciology or climate research.
What Is a Crevasse?
Formation and Characteristics
A crevasse is a deep, open crack that forms in a glacier or ice sheet due to stress and movement. As glaciers move over uneven terrain or accelerate downhill, the brittle ice on the surface fractures, resulting in crevasses. These openings can be found in almost every major glacier around the world and vary in width, length, and depth.
Common Locations
Crevasses are commonly seen
- Near the edges of glaciers where the ice is more vulnerable to stress
- In zones of faster glacial movement, such as near icefalls or steep descents
- Where the glacier moves over obstacles or uneven terrain
Average and Maximum Depths
Typical Depth Range
On average, crevasses can be anywhere from 10 to 40 meters deep (approximately 33 to 130 feet). This range is common in many glaciers around the world, and even at the lower end of that spectrum, a fall into a crevasse can cause serious injury or death due to impact and cold.
Maximum Known Depths
In some cases, crevasses have been recorded at depths of over 45 meters (about 150 feet), and under certain extreme glacial conditions, depths of up to 60 meters (nearly 200 feet) are possible. These deeper crevasses tend to form in very thick glaciers with substantial vertical movement, such as those in Antarctica or parts of the Himalayas.
Why There’s a Limit
Crevasses do not extend indefinitely downward. At a certain depth usually around 50 to 60 meters the pressure from the overlying ice becomes so great that the glacier ice becomes plastic, meaning it flows rather than fractures. This plastic behavior at depth prevents cracks from continuing beyond a certain point, which is why crevasses have a practical maximum depth.
Factors Influencing Crevasse Depth
Ice Thickness
Glaciers with thicker ice are more likely to produce deeper crevasses. The upper, brittle layer of ice can be tens of meters thick, and deeper cracks are possible within this range. However, once the pressure causes the ice to deform plastically, the crack will no longer deepen.
Glacier Movement
Faster-moving glaciers tend to form larger and deeper crevasses because of the increased stress. Ice that is stretching or accelerating is under more strain, leading to greater fracturing near the surface.
Topography
Glaciers that move over uneven ground or steep inclines often experience stress that results in deeper crevasses. For example, when a glacier moves over a cliff or down a slope, the resulting pull can open up wide and deep cracks.
Temperature and Season
In warmer seasons or regions, meltwater can seep into crevasses and deepen them by lubrication or further erosion. However, colder temperatures tend to maintain sharper and more brittle crevasse edges, possibly supporting deeper, more stable cracks before they are filled or collapsed.
Types of Crevasses and Their Depths
Transverse Crevasses
These run across the glacier, perpendicular to the flow direction. They are often very deep because they form where the ice is under tension from steep descent or flow acceleration.
Longitudinal Crevasses
Running parallel to the glacier’s flow, these are typically shallower than transverse crevasses. They form when the glacier spreads out horizontally.
Marginal Crevasses
These appear near the edges of the glacier where the ice moves more slowly due to friction with the valley walls. While not as deep as central crevasses, they can still be dangerous and often hidden by snowdrifts.
Safety and Exploration
Hidden Dangers
One of the biggest risks with crevasses is their concealment under snow bridges. A person may not see the opening and can fall through the thin layer of snow. These hidden crevasses can be every bit as deep as open ones and are often more dangerous because they’re unexpected.
Crevasse Rescue Techniques
Climbers and glacier explorers are trained in crevasse rescue techniques that involve
- Roping together in teams to prevent solo falls
- Using ice axes and anchors to arrest a fall
- Setting up pulley systems to lift someone out of a crevasse
Understanding how deep a crevasse can be informs these techniques. Equipment must be capable of handling rescue operations at depths exceeding 30 meters in many cases.
Scientific Importance of Crevasse Depth
Glaciological Studies
Scientists study crevasses to gain insight into glacier dynamics, including movement rates, internal stress patterns, and the effects of climate change. The depth of crevasses offers clues about the mechanical properties of ice and the glacier’s response to external forces.
Climate Monitoring
Deep crevasses sometimes serve as pathways for meltwater to travel deep into the glacier. This water can reach the glacier’s base and act as a lubricant, speeding up glacial movement. As climate change causes more surface melting, this process could intensify, leading to faster glacial retreat or calving events.
Technological Exploration
Some scientists have begun using radar and drone technology to map crevasse depth without entering hazardous zones. These tools improve safety and provide more accurate data about the ice’s internal structure and stability.
Crevasses are striking natural features that provide valuable insight into glacial dynamics while posing significant risks to climbers and researchers. While their average depth ranges from 10 to 40 meters, they can extend up to 60 meters in exceptional conditions. Their depth is influenced by ice thickness, movement, topography, and temperature. Understanding how deep a crevasse can be is not just a matter of curiosity it’s vital for scientific research, climate monitoring, and ensuring safety in some of the world’s most extreme environments. Whether visible or hidden beneath a fragile snow bridge, each crevasse carries the weight of natural forces that continue to shape Earth’s frozen landscapes.