When climbing a rock or snow ridge, you are usually under pressure to climb quickly, due to factors such as changing weather conditions. Moving lightly on this kind of terrain means you'll be less exposed to electrical storms and you can complete the route in the desired time, without pressure.
During a descent it's also possible to use natural anchors to position a rope for a rappel so that you don't have to leave as much of your own equipment behind, which is a great resource if you find your almost out of gear.
This is the gear you, or someone else leaves behind on a wall. The most common kinds of fixed gear is glue-in bolts, expansion bolts and pitons. It's normally found at rappel and belay points and sometimes at intermediate points on the pitch for clipping in the rope. You can also find fixed gear in cracks, like knotted cords and stoppers or cams. However, before clipping onto these items, it is essential that you check they're reliable and in good condition for use as an anchor.
This is the gear that's placed and then removed. Cams, stoppers, pitons, ice-screws or snow stakes are the most common. They are used both for setting up an anchor system or for belaying the next pitch. On multi-pitch routes, a great variety of gear may be required for carrying out the climb safely. However, the amount and range of protection used will depend on your level of experience and your technical and physical ability. A strong roped team won't need to carry as much gear as a less experienced one. This doesn't mean safety is compromised, but that a route is safer if the team has more confidence, and this level of confidence comes from experience and mental & physical ability.
To use a natural anchor as protection, you need a cord with a diameter no less than 7mm. Stitched slings offer greater resistance than knotted slings and it's convenient to carry both short and long slings and cords for greater versatility. You can occasionally make an exception and use narrower cords for tying to bolts that have lost the hanger or for sticking out pitons. Of course, the wider the diameter of a cord, the stronger it is.
Before tying to any kind of natural anchor, it's important to check its resistance. Check that the thickness of the rock, tree or ice is strong and stable enough to use as safe protection by trying to move it carefully. On other occasions a visual check is required, for example to see if a natural rock bridge is solid enough. The solidity of a natural anchor will also depend on the type and quality of the rock. Granite is more resistant than limestone, which, in turn is more resistant than sandstone. Then come conglomerate rock and schist. But whatever the rock, it is important to study it before you place the sling or cord. The same rule applies to ice as the quality of an ice column varies in solidity, so care is essential.
Lark's head Knot
It is an interesting fact that this knot greatly weakens the cord or sling. It tightens round the anchor well, especially if this is fairly smooth, but the sling-on-sling effect causes a great deal of friction. When the angle is closed and it grips tightly, the strength of the loop is considerably reduced, as shown in photo 1 (traction is perfect, but loop strength is reduced). The sling isn't weakened as much if it doesn't tighten so much around the rock and if the angle is open, but this means it doesn't totally grip the rock. It can be used, but it's certainly not the best option, as you can see in Photo 2. ( grip isn't perfect but loop strength is greater). The lark's head knot can be used on certain occasions, especially for progression on aid-climbing anchors, but it should be avoided when setting up a belay point, where 100% resistance is required.