On an April morning in 1958, a column of cliff came down beside the Zion-Mount Carmel Tunnel and very nearly closed it. Boone goes back through the warnings and the cave-in that came first, and tells how that rock has been watched ever since.
The long tunnel's been telling on itself since it was sixteen months old. State governors drove it with the flags out in July of nineteen thirty. By November of thirty-one a Bureau of Mines man, Doctor W. R. Crane, had been through that same rock, and his report said parts of it might be close to coming down. Crews rushed in and propped the roof. September twenty-seventh, nineteen thirty-two, they were blasting to widen the bore when a block that ran eighteen feet up past the ceiling let go. Five hundred fifty-five cubic yards hit the roadway. A slide in nineteen forty-two left the park's people with a thought they didn't care for. That cliff would go on wearing back, and someday it might lay the tunnel open. Nineteen fifty-eight was a convoy year. Glen Canyon Dam was going up, and rangers were leading heavy equipment through that dark in long lines. Six thirty-five, the morning of April twenty-eighth. A column of the cliff came away above Gallery Three. Eighty thousand tons, by the estimate. Doctor Crane's warning was twenty-six years old that morning. The rock destroyed the gallery, packed the bore with rubble and very nearly closed it, and the rest went on down into Pine Creek. Not one account I've read puts anybody inside. I've still spent more nights than I should on that hour. Slide it along to noon, put a convoy in the bore with a ranger out in front, and you'd be hearing a different tale from me. They had one lane open by May third. Later they walled off what remained, and instruments have been set to watching that rock day and night. A federal history from nineteen ninety-three adds, very quietly, that some have questioned whether those devices really work. There's a concrete wall in that tunnel with two screened windows in it, and a little gray daylight coming through. On the far side is nothing but air, and the place where eighty thousand tons used to stand.
Photo: Brian C. Grogan, Photographer, 1993, Historic American Engineering Record, HAER UT-39-A-13, Library of Congress · Public domain (U.S. government work; LoC: no known restrictions on images made by the U.S. Government)
