Severe weather over the weekend led to storms that dumped between four and eight inches of rain in Grand Canyon country and spawned a small tornado about 10 miles south of Grand Canyon National Park.The deluge breeched an earthen dam, leading to the evacuation of more than 400 campers and residents from Supai Canyon, which is located about 75 air miles west of the park. During the flooding, the water was running at 4,731 cubic feet per second.