The surface area of the lake increased from 1,300 acres to about 2,200 acres. Because of an extensive cover of logs on the surface of Spirit Lake, a post-eruption bathymetric map could not be constructed. Because of the blockage of the original outlet, surface outflow to North Fork Toutle River will not occur until the lake rises from its present altitude of about 3,440 feet to about 3,600 feet. The pre-eruption altitude of the lake was 2,198 feet. Water was released from Spirit Lake into South Coldwater Creek at controlled rates of 5.7 cubic meters per second, 8.5 cubic meters per second, 11.3 cubic meters per second, and 14.2 cubic meters per second for approximately one-week periods during May 1985.
Dead storage is unknown.
Water is used by PacifiCorp for power development. Watch local newspapers for reports on fish survival. Improved water clarity will be a key to fishing success. During April and May fish tend to congregate near the dam and around streams entering the reservoir. By June, anglers should be able to catch trout throughout the reservoir.