At the crag this weekend a friend carried a small spray bottle of water on her harness. She used it to spray stuck cams to remove them. She said she had even used the technique to snag cams left jammed in cracks at the Gunks. If water can cause cams to release, are cams compromised when they are placed in wet rock?
Your friend is brilliant, if unorthodox. Getting the rock
wet will indeed lower a cam’s coefficient of friction, reducing the grip of the cam lobes and making it easier for you to extract an over-cammed
“We know that cams do not work as well in wet rock,” says Doug Phillips, the founder/owner of Metolius. “In wet rock you want to make sure your cams
are very well placed. Look for constrictions in the crack, and nice tight placements that are not going to move as you climb past them.”
But, adds Phillips, not all wet cam placements are weakened equally. “Rock type and location have a lot to do with how much the water will affect the holding
ability of the cam,” he says. Coarse-grained, clean granite, for example, will be much less affected by water than fine-grained limestone with a thin
biofilm of lichen. “This is a concept,” says Phillips, “that many alpine climbers are well aware of, and they place gear with this in mind.”
Also note, certain types of rock, like sandstone, weaken significantly when wet. After a rainstorm, holds can rip off and the edges of cracks can crumble.
Not only do these routes become more dangerous to climb when wet, a climber also risks damaging the rock and forever changing the climb. In these sensitive
areas, don't climb until the rock is completely dry again, which can sometimes be a full day or more after a heavy rainstorm, and confirm closures
and restrictions before heading back out.
Gear Guy has spoken!
This article originally appeared in Rock and Ice issue 240 (February 2017).