Flash Flood in La Paz County, Arizona

Flooding reported on US-95 near Milepost 104 in Quartzsite. No damages or injuries were reported.

A slow moving low pressure system brought several rounds of showers and thunderstorms across portions of south-central and southwestern Arizona throughout the day on the 15th. Strong southerly flow out ahead of the low pressure system brought in highly anomalous moisture content across the southern half of Arizona, with PWATs surging to 1.1-1.4, which are near record values for mid-October. Along with the highly anomalous moisture values, moderate to high instability values were also present with MLCAPE rising to 1000-1500 J/KG. Bulk shear values between 25-35 kts were also present. The combination of the highly anomalous moisture content, instability, and shear along with the strong dynamic forcing to the east and north of the low pressure system was a recipe for these showers and thunderstorms to produce flash flooding as well as severe wind gusts and hail. The greatest flash flood impact occurred along portions of western Maricopa County in the area from Buckeye to Tonopah, The greatest damaging wind impact occurred in the Tonopah area, where two rounds of severe thunderstorms, one hour apart, impacted causing widespread power outages due to downed power poles, destroyed two mobile homes, damaged dairy farm structures, and resulted livestock losses. Severe hail was also reported with a storm that moved into the Mesa to Scottsdale area during the overnight period.

As the area of low pressure moved eastward on the 16th, lingering moisture resulted in the development of more showers and thunderstorms, mainly concentrated across the higher terrain areas east of Phoenix. One isolated storm in particular developed on a open field near Sun Lakes, resulting in the development of a short-lived landspout during the mid-afternoon hours with no damages reported.