At least 16 people were killed when flash floods struck two rural communities along the Arizona-Utah border. 

From her home in Hildale, Utah, Virginia Black captured a heartbreaking video showing a van and other vehicles being swept away by the raging waters. 

AP reported

The van and SUV were filled with three women and 13 children when a wall of brown water overtook them Monday evening, carrying the vehicles several hundred yards downstream and sending them plunging down a flooded-out embankment with terrifying force. The SUV was smashed beyond recognition. Three people survived, all of them children, in the secluded community that is the home base of Warren Jeffs' polygamous sect.

[...]

Only one person was still missing Tuesday in the border town, and authorities had not identified the dead. The children in the vehicles ranged from 4 years old to teenagers.

At nearby Zion National Park, authorities found four bodies and searched for three missing hikers who set out Monday to rappel down a narrow slot canyon. They left before park officials closed the canyons that evening because of flood warnings, park spokeswoman Holly Baker said. The hikers, from California and Nevada, were all in their 40s and 50s, Baker said. She had no details on their identities

Jeff McAdam of FOX Salt Lake reported this morning on "America's Newsroom" from the area where the vehicles were swept off the road.

Lt. Gov. Spencer Cox said the flooding is one of the worst weather-related disasters in the state's history, describing locals as being "in shock"

McAdam said the roads have since been cleared as the Utah National Guard deploys troops to assist with the recovery efforts. A boil-water advisory is in effect until officials can confirm that tap water is drinkable again. 

Watch the report and video above.