Heavy rainfall associated with slow-moving thunderstorms affected the Sierra Blanca region of southern New Mexico on September 18, leading to rapid runoff and flash flooding in the Village of Ruidoso.
The National Weather Service issued flash flood warnings as runoff rapidly filled the Rio Ruidoso and smaller drainages.
The river crested at about 3.8 m (12.5 feet), prompting at least five rescues from rising water. The flooding caused damage to a mobile home, and triggered debris flows, and road closures. At least one vehicle was swept downstream. No deaths or serious injuries were reported.
Monitoring sites recorded about 31 mm (1.22 inches) of rain during the storm, with locally higher amounts over steep terrain. The rainfall fell over areas burned during the South Fork and Salt fires, where loss of vegetation increased runoff and sediment transport.
The September flood occurred less than three months after a more severe event on July 8, when the Rio Ruidoso reached 6.2 m (20.2 feet), destroying homes and killing three people.
Flash flooding in Ruidoso is expected to remain a recurring hazard during the monsoon season as long as burn scars reduce infiltration capacity and destabilize slopes. Authorities continue to monitor rainfall and river levels closely for signs of additional debris flows and surges.
