The dust storm primarily affected drivers on highways 85 and 86 in Pima County, Arizona. Visibility dropped to under a quarter mile, significantly increasing the risk of accidents. Such storms can escalate quickly, catching drivers off guard and creating dangerous conditions. Even after the storm passes, residual dust can continue to impair visibility. These storms are particularly hazardous for those unfamiliar with monsoon season weather patterns or unprepared for sudden changes in conditions.