JUNEAU -- A Mendenhall Glacier ice cave that had become a popular but increasingly dangerous attraction has collapsed, according to the U.S. Forest Service.
Pictures showing the ice cave's spectacular blue color has made it a desirable, albeit difficult, spot to visit.
"The popularity is mostly in the name only, because it is hard to get to, and most tourists don't have the time or ability to get there," said John Neary, director of the Forest Service's Mendenhall Glacier Visitor Center.
The ice that forms the cave's roof was getting increasingly thin, and Neary had just issued a public warning that it was dangerous to visit before Friday's reported collapse.
One of the guide companies with approvals to work in the area reported at noon Friday the cave had partially collapsed, and remaining thin ice means it is still extremely dangerous, he said.
The guide company, Above and Beyond Alaska, had earlier noted the thinning ice and stopped taking clients there on July 3, he said.
Individuals kept trying to get there, however. There's no trail and getting to the glacier itself involves a dangerous crossing of the bare, rocky peninsula that juts into Mendenhall Lake, or a boat trip through the icy waters to very near the toe of the glacier.
"The state troopers have told us it is their most-rescued location, at least in the Tongass," Neary said.
Juneau Mountain Rescue has to retrieve several hikers from the area every year, frequently with ankle injuries or injuries from falls.
Neary said he issued his warning after viewing the ice cave area from a helicopter on his way to Suicide Basin, from which a glacial outburst recently caused flooding in Juneau. He saw people walking near the edges of ice sinkholes and over the cave's roof.
Even after the collapse, it remains unsafe and unstable, he said.
Neary said he also asked University of Alaska Southeast scientists studying the glacier and the outburst floods whether they were linked to the cave's collapse but said they thought the two events were likely unrelated.
Suicide Basin is on the glacier's opposite flank, he said.
"I think it is just a coincidence -- we had a lot of warm weather early in May and we've had a lot of rain lately, and it really sped up the melting," Neary said.