Ice screws and what good ice actually looks like

Ice protection has a reputation for being sketchy, and that reputation is only half deserved. A properly placed screw in solid, plastic ice is genuinely strong — comparable to good rock gear. The problem is that ice varies more than rock does, and it can change from excellent to useless over the course of a single afternoon of sunshine.

Reading ice from the ground

Blue or clear, slightly opaque ice is what you want. Dense, well-frozen, formed by water freezing steadily. Your tools will thunk in with a solid sound and small dinner-plate fractures, and screws will bite cleanly and produce a continuous curl of ice from the core.

White, aerated ice is full of air. It looks bulky and reassuring and it is weak. Screws in it feel soft going in and the ice around them crumbles.

Ice with running water visible underneath or through it is actively melting and detaching from the rock. Late-season, warm-afternoon ice does this. Water running behind a curtain is a strong argument for going home.

Dark, wet-looking ice in direct sun is losing strength by the hour. The same route that was solid at eight in the morning can be dangerous at two in the afternoon on a bright day.

Chandelier and cauliflower formations — those knobbly, poorly bonded structures — are the weakest common ice type. They will not take a screw usefully. Climb through them if you must and place gear above or below.

Placing a screw

Find good ice first, which usually means clearing the surface layer. The outer few centimetres are often sun-affected, aerated or fractured. Chop it away with your tool until you reach solid material.

Avoid placing near a crack, a fracture line, an edge of the flow, or in a bulge that is under tension. Concave and flat sections are better than convex bulges, which are where ice is most likely to fracture outward.

Start the screw with a firm push and a few turns until the teeth bite, then wind it in. Once it starts cutting properly it should go in with steady effort and produce a clean core.

The angle argument

For a long time people were taught to angle screws upward against the load. Testing has broadly reversed that. The current understanding favours placing screws perpendicular to the ice surface, or angled very slightly upward from perpendicular — the important thing being perpendicular to the surface, not to gravity.

What matters at least as much is that the screw is fully in, with the hanger flush against the ice so it cannot lever. A screw sticking out several centimetres is being loaded as a lever arm on the ice at the surface, which is exactly where the ice is weakest.

When it will not go all the way in

Sometimes you hit rock, or the ice is too thin. A partially inserted screw is much weaker and it must be tied off — a sling girth-hitched around the screw shaft right at the ice surface, so the load acts at the surface rather than at the hanger.

Better, where the ice is thin: look for a thread. A V-thread, or a natural hole through a column, gives a load path through a large volume of ice rather than into a small metal object, and in the right formation it is stronger than any screw.

Screw length

Longer screws are stronger where the ice is deep enough for them. Short screws exist for thin ice, not as a lightweight option. Carry a spread — mostly medium, a few long, a couple of short for thin sections.

Keep them sharp. A blunt screw takes far more effort to place, which matters enormously when you are pumped on vertical ice with one hand on a tool. Sharpening is a specific skill and it is worth learning, or paying someone to do.

Temperature changes the material

Very cold ice — well below freezing — is brittle. It fractures in large plates when struck and screws can crack the surrounding ice as they go in. Warmer ice, close to freezing, is plastic, takes tools with a satisfying thunk, and generally accepts screws better.

Both extremes have problems. Very cold means fracture; too warm means the whole formation is degrading. There is a comfortable middle, and experienced ice climbers plan their days around hitting it.

The judgement that does not come from a manual

Ice climbing rewards conservatism to an unusual degree, because the medium itself is temporary. A route that formed beautifully in December may be rotten in March. A cold snap after a thaw makes brittle ice bonded to nothing.

Look at the whole formation before committing: is it attached at the top and the bottom, or is it a free-hanging column? Free-hanging pillars collapse, occasionally with no warning, and they have killed people. That assessment is made from the ground, before anyone leaves the deck, and it is the most important placement decision of the day.