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Summary
 

A wide swath of 3-6 inches of extremely heavy rain (3-6 inches) fell along the Mogollon Rim south of I-40 from Ash Fork to Parks during the afternoon and early evening of August 18th. The flooding rain moved south through various canyons and washes including Sycamore Creek before emptying into the Verde River east of Paulden. A major flood wave moved through the Verde River gauge at Clarkdale around 9 pm that night with a rise from 1.91 feet to 19.49 feet (32,047 cfs) in 58 minutes. This was second highest crest on this gauge in history. Significant flooding was noted along the river in Clarkdale and Cottonwood as the flood waters passed through. The water moved through the Verde River system overnight into Thursday with rises of several feet noted on the gauges near Camp Verde and above Horseshoe Dam. The water reached the Camp Verde gauge around 9:30 am MST Thursday morning and the Horseshoe Dam gauge on Thursday afternoon. Additional minor flooding of property was reported in Camp Verde.

 
Timeline
Radar Loop August 18th 2:18pm - 6:51pm MST

Radar Loop from 2:18 pm - 6:51 pm MST showing multiple rounds of heavy rain just to the west of the Rafael Fire Scar (outlined in white). The most significant rain fell from roughly 3:30 pm - 6:00 pm MST.

Radar Estimated Rainfall August 18th, 2021

NWS radar estimated approximately 4"-6" of rain fell just west of the Rafael Fire Scar during the afternoon hours on Wednesday, August 18, 2021. The flood wave entered the Verde River near Clarkdale, and continued to travel through the Verde River system on Thursday August 19, 2021.

Wednesday and Thursday August 18-19, 2021

  • Mid Afternoon to Early Evening: Multiple rounds of heavy rain moved through the Rafael Fire Scar and areas to the west. Rainfall rates with these storms ranged from 1-3 inches per hour. Rainfall began to lighten up after 6:00 PM MST with a wide swath of radar estimated totals in the 3-6 inch range.

  • 9:00 PM - 10:00 PM: A major flood wave is detected on the Verde River gauge near Clarkdale as it rises from 1.91 feet to 19.49 feet in 58 minutes. This put the gauge in major flood stage and was the second highest crest in recorded history for this area. Water levels began to gradually fall after 10 PM.

  • 11:30 PM: Law enforcements begins to receive reports of property flooding along Bates Road and the Rio Verde RV Park in Cottonwood.

  • Early Morning Hours Thursday: Additional reports of flooding come in along the Verde River by law enforcement.

  • 5:15 AM - 9:30 AM: The flood waters begin to show up on the Verde River gauge near Camp Verde. By 9:30 AM, water levels had risen from 4.18 feet to 14.23 feet. Water levels began to recede after 9:30 AM. Minor flooding of residential properties were reported in Camp Verde on social media.

  • 12:45 PM - 6:30 PM: High water reached the river gauge above Horseshoe Dam. While it was a slower rise (likely due to attenuation), water levels rose from 6.25 feet to 13.56 feet. The gauge crested at 6:30 PM with water levels gradually falling thereafter.


Pictures and Impacts
RV Park Bates Rd

Flood waters from the Verde River entered the Rio Verde RV Park in Cottonwood. Image courtesy of Majken Schimmel on Facebook

Camp Verde White Bridge

High flow and dangerous conditions were reported in Camp Verde around 1/2 mile from the White Bridge. Image courtesy of Jennifer Dutton on Facebook

Verde Valley Estates Flooding

Flooding was observed Thursday morning in the Verde Valley Estates neighborhood of Camp Verde

Comanche Dr Flooding in Cottonwood

Several roads were closed near Comanche Drive and Cottonwood Ditch due to flooding overnight Wednesday into Thursday morning

  • Flooding occurred at the Rio Verde RV Park in Cottonwood with 2-4 feet of water impacting campers.
  • Bates Road, Comanche Drive, and several other roads were closed due to flooding overnight Wednesday into Thursday morning.
  • While the extent of the damage is not yet known, there was impacts to multiple homes along the Verde River in Clarkdale and Cottonwood.
  • One fatality has been reported with this event.
Hydrographs

 

Verde River Near Clarkdale

The Verde River gauge near Clarkdale rose from 1.91 feet to 19.49 feet (32,047 cfs) in 58 minutes Wednesday night. This was the second highest crest on record.

Verde River Near Camp Verde

The Verde River gauge near Camp Verde rose 4.18 feet to 14.23 feet (12,629 cfs) in 4 hours and 15 minutes Thursday morning.

Verde River Above Horseshoe Dam

The Verde River gauge above Horseshoe Dam rose from 6.25 feet to 13.56 feet (10,400 cfs) over a 4-5 span Thursday afternoon.

Verde River Near Paulden

Further confirming the source of the flood waters was the lack of response from the Verde River gauge near Paulden. This verifies the water entered the Verde River between Paulden and Clarkdale from the heavy rainfall near the Rafael Fire Scar.

 

Meteorology

 

Deep monsoonal moisture was in place across northern Arizona, especially south of the Mogollon Rim. A trough passing to the north of the region provided additional dynamics and lift for widespread shower and thunderstorm activity. Steering flow was toward the northeast with multiple rounds of storms forming across southwest and central Yavapai County before moving over the area near the Rafael Fire Scar. Antecedent conditions also likely played a role as a very wet start to the 2021 Monsoon season may have led to more runoff than usual.

 

Points of Contact

For more information on impacts and general inquiries about this event, please reference the contacts below:

  • National Weather Service: Brian Klimowski, Meteorologist-in-Charge at (928) 556-9161 ext. 222 or brian.klimowski@noaa.gov
    • Tony Merriman, Warning Coordination Meteorologist at (928) 556-9161 ext. 223 or tony.merriman@noaa.gov
  • Yavapai County Emergency Management at (928)713-3020