The National Weather Service issued dust storm warnings Saturday for Maricopa, Pinal and Pima counties as walls of dust swept across parts of Arizona, cutting visibility to less than a quarter mile and turning major roadways into dangerous driving zones.
The warnings mattered immediately because they covered stretches of Interstate 10, Interstate 8, Route 85, Route 86 and Route 87 while motorists were still on the road. In the warned areas, the weather service said visibility was reduced to near zero and urged drivers to avoid the storms if they could, then pull off the road, turn off their lights and keep their foot off the brake if they were caught in one.
In northwestern Pima County, a warning from the National Weather Service in Tucson remained in effect until 10 p.m. MST. At 8 p.m. MST, a wall of dust ran from 15 miles northwest of Santa Rosa to 10 miles southwest of Sells and was moving west at 25 mph. The warning covered Ajo, Pisinemo, GuVo, Hickiwan, Organ Pipe Cactus National Monument, Covered Wells, Gu Oidak, San Simon, Why, Cowlic, Gunsight, Charco 27, Ventana, Pia Oik, Vaya Chin, Santa Cruz, Mountain Village, San Simon West, KuKatch and Kupk, along with Route 85 between mile markers 34 and 76 and Route 86 between mile markers 53 and 101.
In southwestern Pinal County, the Tucson office issued another warning until 9 p.m. MST. At 7:33 p.m. MST, an area of blowing dust was near Eloy and stretched west across the southwest portions of Pinal County. The warning included the northern portions of the Tohono O'odham Nation, Eloy, Picacho, Chui-Chu, Picacho Peak State Park, Cockleburr, North Komelik, Kohatk, Jack Rabbit, Shopishk and East Chui-Chu, plus Route 87 between mile markers 116 and 124 and Interstate 10 between mile markers 205 and 218. The weather service said strong winds topped 50 mph there, and the travel risk was life-threatening.
A separate warning from the National Weather Service in Phoenix covered Maricopa County and Pinal County until 8:30 p.m. MST. At 7:32 p.m. MST, a wall of dust extended from near Randolph to near Arizola to near Chui-Chu and was moving west at 30 mph. That warning included Interstate 10 between mile markers 186 and 204, Interstate 8 between mile markers 137 and 178, AZ Route 87 between mile markers 125 and 130, and communities including Casa Grande, Maricopa, Arizona City, La Palma, Toltec, Big Horn, Kaka, Freeman, Arizola, Randolph, Stanfield, Ak- Chin Village and East Chui-Chu.
One report from the weather service said visibility was dropping to around 20 feet near Eloy, a sharper picture of the same hazard that the warnings were trying to prevent. Arizona is used to bad dust and smoke days, and an EPA map shows the state with some of the worst air quality in the U.S., but Saturday’s warnings were about something more immediate: dust thick enough to erase the road in front of a driver. The next milestones were the expiration times at 8:30 p.m. MST, 9 p.m. MST and 10 p.m. MST, which would show whether the storms were easing on schedule or hanging on longer across the counties.
