The tourists who had visited the famous nature park in Washington had experienced a sight of the sudden ice cave roof collapsing.
However the visitors are already warned not to enter the caves saying that, the area is prone to avalanches.
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The visitors were warned when a woman was killed and five of the other people are injured on the previous day.
Signs warn visitors of the hazards from ice and rock at the popular hiking destination about 70 miles northeast of Seattle.
In fact, there is even a warning board at the spot, which read: "People have been killed and injured in and on the ice caves - be safe, not sorry!"
The warm weather has made the caves unstable this season, and access to the ice caves has been closed until further notice.
The video shows the reaction of the tourists, when they observed the ice caves collapsing.