PHOENIX - After a spectacularly strong monsoon dumped 1.5 inches of rain on northern Arizona’s Vermilion Cliffs in just 15 minutes, it was no surprise that mud and rocks had covered US 89A.
But when Arizona Department of Transportation crews arrived on that day in August 2015, what they saw stopped their bulldozers in their tracks: boulders the size of elephants – 15 feet in diameter – and mud in seven different slides that covered portions of 24 miles of the only road across a wide area north of the Grand Canyon.