Stevens Peak in Mount Rainier National Park, is a committed alpine climb. It's recommended you prepare carefully reading guidebooks and climbing websites, and making sure you have the necessary skills, experience and equipment. You will need to be able to handle wilderness route finding, high angle snow ascent and descent, mixed rock and snow, rock climbing, and challenging terrain. Adequate physical conditioning is critical to ensure success and safety. Each of your party members needs to prepare in kind. Study the weather and conditions right up to your departure as these can change rapidly.
We found very little information on access to Stevens Peak. You can start by ascending to Unicorn Peak and then drop down on high angle snow and traverse perhaps a half mile to the Boundary Peak/Stevens Peak Saddle. From here the topo maps and images may suggest that the route is to simply ascend the summit ridge about one mile. However, there are two gendarmes blocking the way. We found a way on climbers left via a high angle snow traverse around these gendarmes. It took almost three hours to make the 1.5 mile traverse from Unicorn to Stevens.
More information here: http://www.summitpost.org/stevens-peak/232349.
