Why Alaska’s melting glaciers could trigger the next deadly tsunami

.

One August morning, an entire mountainside in Alaska’s Tracy Arm fjord collapsed into the sea, unleashing a tsunami as tall as the Empire State Building. It ripped up forests, stripped nearby islands bare, and created whirlpools powerful enough to drag kayaks offshore. Miraculously, a nearby National Geographic cruise ship survived only because an S-shaped bend in the fjord softened the wave’s impact. Scientists say the incident was a warning: a glimpse of how fragile Alaska’s glacial landscapes have become, CNN reported.

Glaciers retreating, slopes collapsing

Alaska has warmed 4.5°F since 1950, the fastest of any US state. As its glaciers melt, they no longer hold surrounding mountainsides in place. That loss of natural support has set off more than a thousand “slow-moving landslides,” with some slopes shifting more than 10 feet a year. When millions of tons of rock fall into deep water, they can displace enough to create catastrophic tsunamis—some, like Tracy Arm’s, among the largest in recorded history.

A rising risk for cruise tourism

These unstable fjords are among Alaska’s biggest tourist attractions. Thousands of cruise passengers sail daily through the same narrow waters that scientists say could unleash deadly waves without warning. “It’s not because this isn’t a hazard,” said geologist Bretwood Higman of Ground Truth Alaska. “It’s because it just hasn’t happened near a ship—yet.” The US Geological Survey continuously monitors only one major slope, at Barry Arm near Anchorage, leaving most high-risk areas effectively untracked.

Climate change and disappearing ice

The root cause, researchers agree, lies in rapid warming. Melting glaciers expose steep bedrock that expands and contracts with heat, weakening its structure. Heavier rainfall and fluctuating temperatures further destabilize these slopes. “You remove that ice quickly, and the thing that’s been holding the mountain in place is gone,” said Noah Finnegan, a geomorphologist at the University of California, Santa Cruz.

A race against time for better monitoring

Scientists say Alaska’s next glacier-triggered tsunami is a matter of when, not if. Yet with limited funding and equipment, they lack the tools to provide early warnings to cruise ships or communities like Whittier. “We need more eyes and instruments on the ground,” said seismologist Jackie Caplan-Auerbach. “Tracy Arm showed us what we’re missing.”

The warning beneath the ice

For now, experts say survival depends on luck and awareness. Ships caught in open water might ride out a tsunami, but vessels trapped in narrow fjords could face disaster. As Alaska’s ice disappears, the mountains are literally falling apart—proof that the next climate catastrophe may not come from the sea rising, but from the land itself giving way.