When Can You Climb on Wet Rock?

Climbing Wet Sandstone Damages the Rock and Routes

Running water seeps down a sandstone cliff at Red Rock Canyon. Note the dry rock to the left of the wet rock. Don't climb!. Photograph © Stewart M. Green

"Can I climb on wet rock after it rains?" is a common question (Climbing FAQ) that climbers ask. The answer is that it all depends on what kind of rock you plan to climb on, how much it rained or snowed on the rock surface, what the air temperature is at the climbing area, and how much sunshine the rock face is receiving. The answer is also, of course, a judgment issue but it is always smart to err on the side of not climbing rather than climbing wet rock and damaging the rock surface and breaking off holds.

Epic Colorado Rains Saturated Rock Surfaces

In September, 2013, Colorado received epic amounts of rainfall over a week, causing massive flooding as well as saturating rock surfaces at climbing areas along the Front Range. At many areas the rain simply flowed off the hard rock surface and quickly dried after the rain stopped. At other areas like the Garden of the Gods in Colorado Springs, the porous rock surface absorbed water like a sponge, leaving sopping wet rock with fragile flakes and handholds.

3 Basic Types of Rock for Climbing

There are three basic types of rock-igneous, sedimentary, and metamorphic rocks. Igneous rocks are generally hard, erosion-resistant rocks that do not absorb water except in cracks and crevices. Sedimentary rocks are basically recycled rock fragments from sand and silt to cobbles and boulders that are redeposited at other places. Metamorphic rocks are either igneous or sedimentary rocks that are changed or metamorphosed by heat and pressure into a rock that is often dramatically different from its original state.

Igneous and Metamorphic Rocks Fine After Rain

Igneous and metamorphic rocks are the best ones to climb on after rain and snow. They are both composed of hard minerals that are resistant to the erosive power of rain. If you climb on fine-grained igneous rocks like granite and basalt, water quickly runs off the rock surface, often down gullies and water grooves, and the rock surface dries quickly, especially if there is any sunshine.

It's fine to climb after rain at granite climbing areas like Yosemite Valley and Joshua Tree in California, Lumpy Ridge and Black Canyon of the Gunnison in Colorado, and Cathedral and Whitehorse Ledges in New Hampshire.

Sedimentary Rocks Soak Up Moisture

Sedimentary rocks like sandstone and conglomerate, however, are a completely different matter. Sandstones are porous and soak up moisture like a sponge, dissolving cementing agents like clay, calcite, iron, silica, and salt and causing the sandstone to simply fall apart under your hands and feet. Sandstone, wet from rain or melting snow, loses its strength, as much as 75% according to some geologists and depending on the type of sandstone. After very heavy and prolonged rain, not only the surface of sandstone is wet but also the interior of the rock surface, sometimes as much as a couple inches below the surface. Often times sandstone will be dry on the surface but still wet beneath. Sandstone climbing areas that are dramatically affected by precipitation and can be easily damaged include the Garden of the Gods, Zion National Park, the cliffs and towers around Moab, Red Rock National Conservation Area, and Indian Creek Canyon.

Climbing on Wet Sandstone Destroys Routes

Climbing on wet sandstone causes degradation of the rock and damages routes because the hand- and footholds break apart and flakes fall off.

It is difficult sometimes to gauge when sandstone is dry enough for climbing without damaging the rock surface. The Bureau of Land Management office in St. George, Utah, which manages lots of sandstone climbing areas in southwestern Utah, says on the climbing page on its website: "Do not climb in damp areas less than 24 hours after rain." It also says: "Wait at least a week in winter and early spring and when there is high humidity, cold temperature and already moist conditions."

When is it Okay to Climb After Rain?

So when is it okay to go climbing after rain or snowmelt? How should you assess the surface of sandstone rock formations to determine if your climbing will damage the surface and degrade or destroy routes and boulder problems? What are the factors that affect the drying of sandstone?

Find out the answer to these questions in the second part of 6 Tips to Assess Wet Rock Before Climbing