Could there have been people camped at the top? I know there are access points to the rim of Arch Canyon. But I understand. I've never seen anything come down in the Moab area. But have watched VW Bus sized boulders fall 1000's of feet in the Wasatch on two occasions in the backcountry.
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"80 series, with a fridge"
1976 FJ40, Project with little progress.
2004 Starcraft 10RT