Glaciers are melting in Alaska, which is making its tourist centers wonder what the future brings.

The Mendenhall Glacier is a star attraction for Juneau, Alaska’s capitol city. Every year, it’s swarmed by sightseers via bus, hiking trials, kayaks, and even helicopters. So many come that many residents of the city leave to quieter places for the summer, and the city has had to impose a limit to how many cruise ships are allowed to make port. Despite the limits, tourism numbers this summer are expected to break all records.

But Mendenhall won’t be there forever. Climate change is making the glacier recede. When the Mendenhall Glacier Visitor Center was built in 1962, the glacier towered above it. Mendenhall Lake, which has only existed since the glacier receded from its basin in the 1930s, has only grown, and now the visitor center sits opposite the glacier across over a mile of lake. If it recedes at its current rate, without accelerating, the glacier will not be able to be seen from the visitor center by 2050.

“We need to be thinking about our glaciers and the ability to view glaciers as they recede,” said Alexandra Pierce, the city’s tourism manager. There also needs to be a focus on reducing environmental impacts, she said. “People come to Alaska to see what they consider to be a pristine environment and it’s our responsibility to preserve that for residents and visitors.”

The spectacular views aren’t the only thing at risk. On Monday, an outburst of meltwater from beneath the glacier flooded lake Mendenhall and raged down the Mendenhall river into Juneau, destroying several buildings, mostly condos and homes as rapid erosion undermined the buildings. The flood, the worst of several in recent years, might be evidence that the glacier is melting faster than predicted.

Another Alaskan site is a cautionary tale – the Begich, Boggs Visitor Center, near Anchorage, can no longer see more than a splinter of one of the three glaciers it was meant to overlook. From over 400,000 visitors in its heyday, it now sees perhaps 30,000 a year, mostly hikers meaning to go to where the glaciers are before they’re gone.