The impact of the 63.5 million cubic meters of rock that hit the fjord released forces large enough to be recorded on a global scale. Seismic waves cascading on the planet were recorded by sensor stations around the world and were equivalent to a 5.4 magnitude earthquake in terms of energy. The capricious water inside the fjord created a 66-second long seiche, a standing wave that reverberated back and forth for 36 hours.
“It could easily turn into a catastrophic disaster,” says Fathian. This may be because Tracy Arm is a very popular tourist destination.
Close call
More than 20 boats ply the Tracy and Endicott tributaries daily, including up to six large cruise ships during the summer months. If the landslide had happened a few hours later, in the middle of a tourist day, the result could have been tragic. But even at 5:26 a.m., the tsunami was enough to scare the few people around.
About 55 kilometers away on Harbor Island, a group of kayakers saw water flowing past their tent 20 minutes after the slide. The rising tide washed away some of their gear and one of their kayaks. In nearby No Name Bay, spotters on a motorboat reported a 2 to 2.5 meter crest wave coming along the beach from the direction of Tracy Arm, followed by a secondary 1 meter wave.
85 kilometers from the source, the crew of a small cruise boat anchored at Fords Terror saw a wave of water spill over a nearby sandbar; then he physically lifted the ship three meters despite the tide. They said the swell continued until 11 a.m., leaving their small boat stranded on dry land only minutes later when the water receded.
The National Geographic Venture cruise ship, carrying about 150 people, anchored in dense fog at the mouth of the fjord. The captain noted currents, whitewater, and significant amounts of ice and debris at the edges of the fjord. The people on the cruise ship escaped unscathed as the jagged, shallow seabed near the mouth of the fjord acted as a speed bump that sapped the energy of the wave. “It was a miracle that no one was hurt,” says Fathian.
