Flood waters from a breakout could be more catastrophic than the lahars of May 18, 1980. Gages, such as this Early Warning Gage on Coldwater Lake, have been installed at lakes and streams surrounding the volcano. These gages continuously monitor changes in water levels. Major increases or decreases in levels trigger warnings which are telemetered to the U. S. Geological Survey in Vancouver. In foreground is confluence of Loowit, North Fork Toutle, and Castle drainages.
Spirit Lake is in middle right.
Interstate 5 Bridge in middle left background. Note mudlines left behind on trees. This area was later logged and dredged. A mudline left behind on trees shows depths reached by the mud. This view is along the Muddy River, southeast of Mount St. Helens.