A dust storm warning (DSW) is an alert issued by the U.S. National Weather Service when blowing dust is expected to reduce visibility to ¼ mile (400 meters) or less, typically accompanied by winds of 25 mph or more. Since November 1, 2018, these warnings have been issued in a precise, polygon-based format (similar to tornado warnings) to pinpoint specific danger zones, while a lesser "dust advisory" is used for lower-impact conditions. For example, on July 5, 2018, the Phoenix office issued a warning for Maricopa and Pinal counties, describing a wall of dust moving at 20 mph with winds exceeding 40 mph, making travel "dangerous and life-threatening." The alert includes critical safety advice: if caught in a storm, motorists should pull off the pavement, turn off their lights, and keep their foot off the brake pedal to avoid chain-reaction collisions. Officials often underscore the danger with the slogan "Pull Aside, Stay Alive!" to prevent drivers from entering blinding dust walls.