One of the most popular trails within Grand National Park is being closely watched after winter storms triggered a series of rock slides. Powerful rains and melting snow are attributed for several rock falls in northern Arizona. The Arizona Department of Transportation closed State Route Highway 89A closed after a rock slide Tuesday. Then a boulder big enough that it required a bulldozer to move it fell on the highway. In Grand Canyon National Park, officials say they found three rockfalls along the popular Bright Angel Trail on Wednesday alone. Joelle Baird with the Grand Canyon said the rockfalls were on the upper three to five miles of the trail, most popular with hikers...