The dust storm in the Phoenix area Tuesday has left a massive cleanup task and health concerns for people with respiratory conditions, officials said. The storm the National Weather Service Forecast Office in Phoenix called "very large and historic" was estimated to reach a peak height of almost a mile with the leading edge stretching nearly 100 miles, AccuWeather.com reported. Such dust storms are common in the U.S. southwest during the summer, a time of high thunderstorm activity. The thunderstorms can produce strong downdrafts, or "downbursts," which are powerful winds that blast downward and outward from the storms. "When this happens, dry, loose sand on the desert floors can get kicked up, creating a wall of dust that travels outward, spanning a much larger area than the thunderstorm itself," AccuWeather meteorologist Jim Andrews said. The storm cut power to 10,000 area customers, grounded flights at Phoenix's Sky Harbor airport and left people cleaning up cars and pools covered in dirt and mud, The Arizona Republic reported. Because of lingering dust, people with asthma and others with respiratory issues were warned to stay inside. "It's a little bit frantic today," Dr. Laura Ispas-Ponas of the Sonoran Allergy and Asthma Center in Scottsdale said. "Patients are calling complaining of symptoms that seem to be, but aren't necessarily, allergy-related." Dust can cause serious reactions in people with asthma, chronic obstructive pulmonary disease and other respiratory conditions, she said.