Climbing Mt St Helens is an excellent activity to add to your list of things to do in Washington if you're looking to spend time outdoors and explore the mountains for which the Pacific Northwest is famous. The summit of the volcano stands at 8,328 feet, with beautiful views of the crater, the surrounding area and, on clear days, other volcanoes in the chain, such as Mt Rainier, Mt Adams, and Mt Hood. After St Helens erupted in May 1980, the mountain was entirely closed to the public, but in 1987, the south slopes were reopened to climbers. There are two main routes to get to the summit of Mt St Helens, and both are difficult. The climb is less technical than Mt Rainier, so previous rock climbing experience isn't necessary, but climbers do need to be in good physical shape.
Monitor Ridge Climbing Route
The climb along Monitor Ridge is the summer route, and it's also the more popular of the two routes to the summit of Mt St Helens. The trail begins at the Climbers Bivouac, at the end of US Forest Road 830, on the Ptarmigan Trail. This route can be closed through June and even into early July if there is still snow, but it typically opens in late spring. The climb to the summit is 10 miles round trip and typically takes between 8 and 12 hours. The first 2.1 miles are the only portion of the hike that's actually on a trail. It winds through the forest slopes and switchbacks up through 1,000 feet of elevation gain. Once you get above the timberline, the next 2,500 vertical feet are gained by scrambling over large lava boulders. There is no set trail; simply follow the row of wooden posts along whatever route suits you best. The rocks are rough and can scrape up your hands, so some climbers choose to bring gloves. The final 1,000 feet to the summit goes through volcanic ash and scree. The hike from Climbers Bivouac can be done during the day, or you can begin in the very early morning and get to the top of Mt St Helens in time to watch the sun rise.
Worm Flows is the 10.8-mile round trip winter route to the summit of Mt St Helens, though it can also be climbed in fall, spring, and summer—basically, any time at which there is still enough snow that the road to Climbers Bivouac is closed. The trail begins at Marble Mountain Sno-Park and follows cross-country ski trails through the fir trees for about the first two miles, before leaving the forest and passing Chocolate Falls, a 40-foot waterfall on Swift Creek. The Worm Flows route crosses the lava field as well, both mudflows and the large boulders, and hikers find their way via the row of wooden posts marking the way to the summit, before reaching the loose ash and scree for the final portion of the hike. Ash and loose gravel can be slick, and this route requires extra gear over what you might bring on the Monitor Ridge hike. Specifically, crampons and ice axes can be useful here.
What to Bring
If you plan to hike above the timberline, you will need a permit. These can be bought ahead of time online from the Mt St Helens Institute, and then picked up at the Lone Fir Resort in Cougar on your way to the mountain. After May 15, only 100 people are allowed to summit the volcano on any given day, and once permits go on sale in early February, the weekends sell out very quickly.
Bring plenty of water, at least 3-4 liters per person, or more if you're climbing on an especially hot day. There is no water on the trail and none at the camping areas. Bring enough high-energy food for several small meals or snacks, and also bring sun protection, including sunscreen, sunglasses, a hat, and lip balm with an SPF. Hiking boots should be waterproof and lug-soled, including ankle protection, and gaiters are useful as well, particularly on the scree, for keeping ash, rocks, and snow out of your boots. Dress in layers, as the weather can change rapidly, and bring a first aid kit and a flashlight or headlamp, even if you don't plan to hike after dark. Trekking poles are helpful, especially if you're descending down the lava boulders, but on both routes it's possible to glissade down the snow fields, which saves both time and energy on the descent. If you plan to do this, bring something to sit on, such as a garbage bag, and an ice axe to use as a brake.
Whichever route you climb, be very careful at the summit. There are snow cornices (overhangs) that may appear to be solid but actually have no support beneath them; they can break off and fall into the crater with very little warning.
If you're concerned about hiking on your own, there are guided climbs held on several Fridays and Saturdays throughout the summer, though not every week. In addition to help with the climb, you'll also get a lot of interesting knowledge of the mountain and its history, as many of these climbs have a geologist come along with the hikers.