**Update 9/15/15 2:30: KUTV News says it can confirm 12 deaths, with one person still missing.
**Update 9/15/15 2:15: two additional victims have been located. The death toll is now 11, with one person still missing.
**Update 9/15/15 1:30: another victim has been located, bringing the official death toll to 9.
An active search-and-rescue mission continues along the Arizona-Utah border after a flash flood Monday afternoon killed at least eight people.
Authorities from the Washington County Emergency Management Office say they are aware of five missing people in the Hildale, Utah area — local news station KSL reports that one of the missing is a grown woman, that the other four are children, and that at least one survivor remains hospitalized.
A late-summer storm gathered power Monday afternoon as it moved northeast from Mohave County, Arizona, into Washington County, Utah.
Mike Conger with the National Weather Service in Salt Lake City says that the rain began falling about 3 p.m. and dumped two inches in less than an hour.
(Heavy rain also fell near Zion National Park, and flash-flood warnings also were put in place for the area.)
Vortex image of BIG storm over Hilldale yesterday. Very heavy rain. pic.twitter.com/MLcQLEv8qa— Grant Weyman (@KSLweyman) September 15, 2015
But the worst of the storm hit the Colorado City-Hildale area, where 6-10,000 members of the Fundamentalist Mormon polygamist faith live.
"Heavy rain fell in what is called the Short Creek drainage and sent a flood wave back to Hildale," Cougar says, adding that from where he sits in Salt Lake City, "it looks like it was a very intense flood. Probably one of the larger ones [in recent history] based on damage and loss of life."
The Washington County Emergency Management Facebook page, Washcosafety, states that at "5 PM heavy rains caused flash flooding in the Hildale area. The flooding caused extensive damage and several vehicles were washed downstream. In the flash flooding, two occupied vehicles were hit by a large wall of water and debris at the Canyon Street Maxwell Crossing and were carried into the Flood. There were 16 people with the vehicles who were washed downstream by the flooding."
While the worst of the downpour ended by the evening, rain continued throughout the night, and flash- flood warnings remain in place for southern Utah and northern Arizona.
Washcosafety also reports: "Fire and public works crews worked through the night monitoring flood crossings and searching the banks of Short Creek; A large contingent of contractors, using heavy equipment, are working to clear thousands of tons of mud and debris from the Central Street creek crossing; [and] the search effort will continue and resources will be increased this morning, weather permitting."
The NWS reports that "heightened flows are anticipated to remain in the area through the afternoon hours [and] additional thunderstorm activity is expected."
The Washington County Emergency Management team did not immediately return requests for comment.
Check out some photos of the damage from Colorado City resident and photographer Melissa Dockstader Zitting: