The only access is via the Harmony Falls Trail which leads to the northeastern shore of the lake. The Spirit Lake basin and Toutle River valley (Class I Research Area) are closed to public access, except on developed trails. Restricting public access to the valley directly north of the volcano and Spirit Lake helps protect opportunities for long-term research. By preserving this important natural laboratory, we ensure that future visitors will have an opportunity to learn about nature’s recovery processes at Mount St. Helens.