Get Outdoors - Mountaineering Basics: Position/Stance: Position & Anchor

Your position relative to the anchor or anchors when belaying off your harness is straightforward: make sure you are tied in as close as feasible to the anchors, with no slack, so that you won't be jerked about by a severe fall.When you are belaying a follower, this tie-in only needs to hold a downward pull. But remember that in the event of a leader fall you cannot be sure whether the force will be upward (most likely) or downward (unlikely but potentially deadly).

In settling on your position in relation to the belay anchors, think through the possibilities of what could go wrong given this or that position and this or that kind of fall. Then draw your best conclusion about the optimum arrangement.

Consider an upward pull first: Maintain a fairly tight tie-in to an upward-pull anchor somewhat below your waist. A standing, rather than a sitting, position is best for this tie-in.

In a severe fall, you as the belayer may be jerked sharply upward for a few feet, especially if you are much lighter than your partner. This can cause you to lose control and can result in injury if you are yanked up against an obstruction. It can even result in the downward-pull anchors pulling out if they are not multidirectional, leaving you and your partner hanging from the top piece of protection.

Now consider an unprotected leader fall where the force is downward: Make sure to be tightly attached to anchors above your waist so that you cannot be pulled down more than a few inches. (You might also develop a preference for a sitting stance or for belaying directly off the anchor.)

Scenario: You are in a standing belay of a leader, with a fairly long attachment to an anchor at about waist height or lower. You are standing on a belay ledge, your partner falls past you, you try to brace yourself and go into the braking position, and the force downward on your waist builds quickly toward the point where the rope will start to run. Do you think you can stand there and stop the fall? No. You would be pulled violently off the ledge or driven sharply down onto it, with almost certain loss of control of the belay and probable injuries.
You, the belayer, are not prepared to stop an unprotected fall, if you are in a standing belay of a leader, with a fairly long attachment to an anchor at about waist height or lower. Avoid this risk by being tightly attached to anchors above your waist so that you cannot be pulled down more than a few inches.