Crevasse Safety and Rope Team Travel
A glacier's surface looks like terrain. It is not. Beneath a skin of consolidated snow lie gaps in the ice that can be metres wide and tens of metres deep, concealed by fragile snow bridges. The rope is the one piece of technology that converts glacier travel from a game of chance into a managed risk — but only if everyone on the team understands how to use it before they step onto the ice.
Why you never travel a glacier alone
A person who falls into a crevasse without a rope is in a situation that is very nearly unrecoverable without outside intervention. Even a short fall — two or three metres — leaves the victim wedged in a narrowing shaft of ice with arms pinned, unable to climb and rapidly losing core temperature. With a rope and a partner who did not fall, a crevasse rescue is hard but achievable. Without one, rescue depends entirely on other parties being close enough to hear the call. Solo glacier travel is not a calculated risk; it is an unnecessary gamble. Every experienced mountaineering organisation, from the UIAA to the American Alpine Club, states this without qualification: glaciers are roped terrain.
The rope team and spacing
The standard glacier rope team is two or three people. A two-person team requires each member to be highly competent in crevasse rescue, since the uninjured partner must manage the arrest and the hauling system alone. A three-person team — the most common recommendation for moderate glacier travel — distributes the load: one member holds the fall while the other assists the haul.
Rope spacing between team members should be 8 to 15 metres on a roped glacier traverse. Shorter than 8 metres risks both members crossing a snow bridge simultaneously; longer than 15 metres creates slack that is difficult to arrest quickly. On heavily crevassed terrain, team members take up the extra rope as coils carried in the hand, which shortens the active rope between them to around 8 metres while keeping the full rope available for hauling.
Each member clips into the rope with a figure-eight knot on a bight to a locking carabiner on their harness. The rope runs directly between members; no short-roping around the waist, which can injure a falling climber on a sudden stop.
Arresting a crevasse fall
When a team member breaks through a snow bridge, the response is immediate and automatic: every other team member drops into an ice-axe arrest, driving the pick into the snow surface and pressing their body weight over the shaft. The arrest must happen before the full weight of the falling climber comes onto the rope. This is why glacier teams move with the rope slightly taut, not dragging slack behind them.
The arresting team member calls out the fall to the others, assesses the situation, and begins transitioning to a haul without releasing the arrest. This transition — building an anchor while maintaining tension on the rope — is the hardest skill in crevasse rescue and the one that most demands practice on dry ground before it is needed on ice.
The 3:1 Z-pulley rescue system
The standard crevasse rescue technique is the 3:1 mechanical advantage system, also called the Z-pulley. The uninjured party anchors the loaded rope using two snow pickets or ice screws, then builds a pulley system that runs the rope through a redirect at the anchor and a moving pulley on the victim's end, creating a three-to-one mechanical advantage. This reduces the pulling force required to raise the victim to roughly one-third of their body weight — typically achievable by a single rescuer.
The components required: two snow pickets or ice screws, three locking carabiners, two pulleys (or the carabiners can substitute in an emergency), and two prussik loops. A 5 mm or 6 mm prussik loop of 1.2 m circumference catches the rope on each backslide, allowing the rescuer to reset without losing height.
Key details that are often missed in training: the lip of the crevasse is the primary friction point and the primary danger for the rope. Pack out the snow lip with an ice axe shaft before hauling, or the rope will cut deeper into it with every pull, increasing friction and risking a lip collapse.
Prusik loops and personal ascent
Every member of a glacier rope team carries at least two prussik loops — short slings of 5 or 6 mm accessory cord that grip under load and release when unloaded. A victim who is conscious and physically able can assist their own rescue by attaching a prussik to the rope above them and a foot loop to stand in, climbing the rope while the surface party hauls. This dramatically reduces the load on the hauling system and is often the deciding factor in a successful rescue.
The setup: one prussik attached to the harness with a locking carabiner, positioned as high on the rope as the outstretched arm can reach; one foot-loop prussik attached to the first, long enough to allow the knee to bend at approximately 90 degrees when standing. Alternate between standing in the foot loop to push up, and sliding the upper prussik higher. Practice this on a fixed rope at home — inside a crevasse is not the first time to work through the mechanics.
Probing and recognising snow bridges
Probing — testing the snow surface ahead with a ski pole or dedicated probe pole — is the primary crevasse avoidance technique. Hold the pole vertically and probe every step in suspect terrain: hollow resistance, a sudden drop-through, or an asymmetry in resistance between adjacent probes indicates a void below.
Snow bridges that bear weight in cold morning conditions can collapse in the warmth of afternoon. Many experienced guides cross heavily crevassed glaciers exclusively in the cold pre-dawn hours and are off the glacier by midday. This is not excessive caution; it is a direct response to known failure rates of snow bridges as temperature rises.
Visual indicators of crevasse zones: slight depressions in an otherwise flat snowfield, areas where the snow surface is fractured or shows linear cracks, and transitions between the convex upper glacier and the steeper lower glacier where tension crevasses form perpendicular to the flow direction.
Summer versus winter risks
In summer, surface snow melts away to expose blue ice, making crevasses visible and therefore navigable without probing. The danger is calving, wet ice for crampons, and water-filled crevasses that are hypothermically dangerous. In winter and spring, deep snow conceals crevasses completely, makes probing essential, and creates the avalanche hazard on the approach slopes that often presents a greater risk than the glacier itself.
Find the glaciers on the map
Every glacier referenced in this guide is plotted on the interactive map. If you are researching a specific glacier approach, use the map to identify the access point and then contact a certified mountain guide in the relevant region before setting out.