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Summary
 

In the early morning hours (just before 4am MST) of September 26, 2019, a strong thunderstorm moved through the Spring Valley area in Yavapai County. A Severe Thunderstorm Warning was issued by the National Weather Service office in Flagstaff at 3:48 AM MST, continuing through 4:15 AM MST. Damage to several mobile homes and at least one power pole has been reported. A storm survey was conducted and it was determined that straight line winds around 75 mph was the likely culprit. Along with the strong storm, a Flash Flood Watch was in effect for Yavapai County. There were reports around the county of localized flooding throughout the morning hours.

 
Timeline
Radar reflectivity of the storm as it moved through Spring Valley

Radar Reflectivity from 3:28am MST to 4:02am MST as the storm moved through Spring Valley.

Radar velocity of the storm as it moved through Spring Valley

Radar velocity of the storm as it moved through Spring Valley. There was some weak rotation noted on the radar with this storm as it approached Spring Valley.

  • September 26, 2019 at 3:48 AM MST:  A strong thunderstorm was detected on radar by staff at the NWS Flagstaff office. A Severe Thunderstorm Warning was issued.

  • September 26, 2019 at 4:15 AM MST:  The storm showed signs of weakening at 4:15 AM MST and the Severe Thunderstorm Warning expired.

  • September 26, 2019 at 9:00 AM MST:  Fire emergency management called the NWS Flagstaff office to make them aware of considerable damage to mobile homes and at least one power pole in Spring Valley. The area was without power for several hours.

  • September 26, 2019:  An NWS Storm Survey team traveled to Spring Valley and conducted a storm survey. It was determined that straight line winds around 75 mph was the likely culprit.
Impacts
  • Approximately 20 mobile homes were damaged, with one no longer habitable. 4 homes suffered moderate damage.
  • At least one power pole was snapped, and the area was without power for much of the morning.
  • Several trees were estimated to have been damaged.
Pictures

 

Trampoline destroyed in Spring Valley

Trampoline destroyed in Spring Valley

A power pole was snapped in half during the storm

A power pole was snapped in half in Spring Valley

A mobile home had significant damage to its roof

Dry tall grass is seen in the foreground with considerable damage to the roof of a mobile home in the distance

The awning of a mobile home was separated from the main structure

The awning of a mobile home was separated from the main structure

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Arial photo of damaged mobile home. Courtesy of Yavapai County Development Services

Meteorology

A low pressure system which had been centered over southwest Arizona lifted north, bringing increased moisture into the area. This helped generated shower and storm activity in central Arizona late in the evening on September 25th. The storms spread to the northwest into Yavapai County in the early morning hours of September 26th. Enough instability and wind shear was in place for the development of a strong thunderstorm which tracked through Spring Valley around 4am MST.

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) 771-3183 or web.public.works@yavapai.us