Fourteen-year-old Darwin Steffler was in bed in his family’s lakeside lodge about 5.5 miles east of here when he felt the earthquake strike. After checking on his little brothers, he ran through the darkened house to the front window and, through the dust and moonlight, saw the lake dropping while water gushed across the breakwater of the lodge’s marina. Thinking Hebgen Dam had broken and the lake was draining, he ran to retrieve a loose boat, but as he walked it back to shore the water rose swiftly and he soon was swimming for his life. What he witnessed was a tsunami-like wave called a seiche, caused by the sudden tilting of the land under and around the lakebed. These waves damaged lakeshore buildings and roads already harmed by the earthquake, wrenching cabins off their footings and leaving a scar in the hillside where the highway once ran. When the ground dropped along the Hebgen Lake Fault, water was displaced from the south shore to the north shore, making it feel as though the lake had tilted. Land was lost along the north shore and gained along the south shore. The lake sloshed back and forth several times, alternately swallowing and exposing shoreline, and afterward the northwest arm had flooded beaches, docks, and roads while the southern shore left docks and boats stranded far from the water. The tilt also increased the lake’s storage capacity by 2.6 billion gallons, the equivalent of 6,640 Olympic-sized swimming pools.