Lakes Trail Professional Review and Guide
"Before May 18, 1980, this was a forest, not a lake. The volcanic eruption that day, however, swept away the forest, and the massive mudflows in the Toutle River Basin created a huge earthen dam that trapped the waters of Coldwater Creek and formed the new lake.
This area is still very fragile, and hikers must stay on the established trail—indeed, anywhere you find blast destruction, it’s a good idea to stay on the trail as much as possible. The ash-soil is very light and easily disturbed."