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The elements and time finally caught up with the Sentinel, a signature formation at Bryce Canyon National Park that seemed to defy gravity for decades.

In recent days, the top 15 feet of the spindly hoodoo, a favorite perch for the park's ravens, crashed to the earth, an inevitable event that was probably triggered by frost wedging.

"This is a hoodoo people would stop and look at and wonder if it would fall and they would see it," said Joel Allen, an interpretive park ranger.

The hoodoo, whose collapse was discovered Tuesday, is near the Navajo Loop Trail, behind another famous formation called Thor's Hammer.

Allen hiked to the site and found no evidence that its fallen pieces hit the trail.

"The most I could find was a suspect boulder, only about 4 or 5 feet long, caught high up, very precariously wedged in a small alcove," Allen said.

Hoodoos are the eerie multi-hued reddish towers and fins eroding out of the eastern and southern walls falling off the Paunsaugunt Plateau, one of the upper treads of southern Utah's Grand Staircase.

The Sentinel's collapse illustrates how Bryce's famed formations are constantly changing, with some falling apart as new ones emerge imperceptibly from the limestone matrix.

"We notice hoodoo destruction more than hoodoo formation because one is swift and big, and the other quietly shattering the rock faces and covering the ground in angular gravels," Allen wrote in a post on the park's Facebook page.

Usually the changes are too small to notice, but major rock falls are common. The biggest losses occur during seasonal transitions in late fall and early spring.

Two and a half months ago, for example, a fin collapsed off the Wall Street formation just a quarter-mile from the Sentinel.

"Even if it looks coherent it is full of vertical fractures. They can be pushed apart and you get a collapse," Allen said. The Wall Street area is often strewn with freshly fallen boulders in spring.

And last year, park officials discovered that the formation known as the Turtle, located off the Mossy Cave Trail, didn't look so much like a turtle anymore — perhaps more like a double-stalked mushroom.

No one knows exactly when the Turtle lost its head; the change was noticed by a Salt Lake Tribune reader after she saw a photo of the intact Turtle posted on the paper's "Where Is It?" feature in March 2015.

And this week's collapse was not the first for the Sentinel. In July 1986, its top 10 feet fell only moments after a park ranger led visitors past it. It remained a towering feature, notably tapering to a waist about 2 feet across. That narrow spot is where it failed Monday night.

Allen figures water had been gathering in the hoodoo at that vulnerable location. With recent freeze-thaw cycles, ice formation destabilized it to the point where it succumbed to gravity.