MOUNT ST. HELENS, Wash -- The U.S. Forest Service is recommending safety to anyone who makes the arduous, but not technical, 5-mile hike to the crater rim of Mount St. Helens.

The Forest Service allowed the resumption of climbing beginning on July 21.

In addition to basic backcountry necessities such as a compass, map and plenty of water, they recommend that climbers bring an ice ax, sunglasses that seal around the eyes to keep dust out, a dust mask, and a climbing helmet, just in case the volcano sends rocks soaring above the rim.

Permits are required to hike above tree line and cost $22 each. The Forest Service will issue up to 100 permits a day, and reservations can be made on the Internet through the Mount St. Helens Institute.

The entire south side of the mountain is being reopened to climbers, as are trails through the blast zone on the north side. The crater itself remains off-limits.

The most popular climbing route begins on the south side at Climber's Bivouac, elevation 3,800 feet. An easy trail through firs and huckleberries on an ancient lava flow leads to tree line at Monitor Ridge, at 4,800 feet. That's where the scrambling starts, up broken rocks and pumice, through sparse patches of subalpine grasses and flowers, to 7,000 feet, where the trail soon becomes a thick field of ash -- like hiking up a steep, sandy dune.

When climbers reach the narrow rim and look into 1.2-mile-wide crater, the ascent's difficulty is quickly forgotten -- especially when they consider that nearly everything they see on the floor 2,000 feet below has built up since 2004.