The slide caused seismic tremors that first registered at magnitude 2.9, , according to data from the Alaska Earthquake Center. But that magnitude was computed as if the tremors were from an earthquake. Scientists at the center later recalculated the magnitude and came up with a higher figure, 5.5.

The source of the slide appears to be a peak on the west side of the glacier that was more than 6,500 feet high. It is unclear how much rock broke away, but an early estimate from the Lamont-Doherty Earth Observatory suggested the slide involved more than 132 million tons of material.

The Alaska Panhandle in and around Glacier Bay National Park has been the source of many large landslides in recent years.

Scientists say the slides will most likely continue as warming temperatures cause more glacial melt. Glaciers buttress the mountainsides that surround them; when the ice disappears, the slopes lose some of their support, and erosion or earthquakes can cause them to collapse.