A towering wall of dust more than 100 miles long swept across metropolitan Phoenix late on 25 August, prompting the National Weather Service to issue dust-storm and severe-thunderstorm warnings for Maricopa and neighboring Pinal counties. The haboob, driven by powerful monsoon downdrafts, reduced visibility to near zero and was quickly followed by intense rain, lightning and strong winds. The storm knocked out electricity to about 60,000 customers and left a swath of wind and water damage across the Valley. Motorists were urged to pull off roadways, while pollution officials issued air-quality alerts as particulate levels spiked. Operations at Phoenix Sky Harbor International Airport were disrupted, with multiple flights delayed or canceled. Preliminary gauges from the Maricopa County Flood Control District recorded 1.18 inches of rain at South Mountain, 0.98 inch at Chandler Airport and lesser amounts across much of the metro area. Forecasters expect widely scattered showers and thunderstorms to persist through 27 August, with a 20%–40% chance of additional activity overnight, as residual monsoon moisture and the remnants of Tropical Storm Juliette linger over southwest Arizona. The weather service warns that any new cells could again produce gusty outflows, brief downpours and hazardous driving conditions.