Blast discharged to remove dangerous rock over cave exit at Timpanogos Cave NMon

HIGHLAND — A single, resounding blast echoed off the walls of American Fork Canyon as tons of rock were sheered off the cliff above the Timpanogos Cave National Monument trail.

"Dang, that sounded good," said a woman's voice over the National Park Service radio frequency.

The blast removed a 30-foot-long slab of rock that hung precariously above a shelter built at the cave's exit. The slab was about 2 feet high and 4 feet deep.

The explosion was powerful enough to shake the snow off the roof of the shelter, which has protected cave visitors for decades from rocks that occasionally tumble down the steep mountainside.

When cave managers decided to rebuild the shelter this year with funds provided by the American Recovery and Reinvestment Act, experts evaluated the cliffs above the shelter and found a 4-inch gap between the cliff and part of the rock slab.

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