Authorities say they believe low visibility from a channel of blowing dust has caused two multi-vehicle collisions on Interstate 10 north of Picacho Peak, one of them deadly.
The Arizona Department of Public Safety said three people died and more than a dozen others were injured in the pile-ups Tuesday along westbound I-10 at milepost 214.
Several medical helicopters were seen on television footage taking some of the injured to hospitals. Injuries ranged from minor to severe, police authorities said.
The victims were identified as Gordon Lee Smith, 76, of Mead, WA; Lenny Lubers, 46, of Phoenix; and David Bechtel, 51, of Milton, IA.
Twenty-one vehicles were involved in the collision. Eleven of them were large commercial vehicles.
"It looks like one big event right now but in reality its probably a series of collisions," said DPS Capt. Brian Preston. "So you may have collisions one and two that became part of three and four."
TV footage showed passenger cars crumpled and tractor-trailers smashed.
The initial 19 vehicle crash, which resulted in three fatalities, occurred within the westbound traffic lanes of the interstate.
A second two-vehicle crash occurred within the eastbound traffic lanes that involved minor injuries and a commercial vehicle.
Members of the U.S. Air Force 48th Rescue Squadron were among those providing initial care to the injured motorists. The squadron happened to be traveling through the area at the time of the blowing dust.
Following the collisions, they were able to triage and provided critical medical care to the majority of the patients on scene. Members of the squadron also coordinated the on-scene approach and departure of the three responding medical helicopters.
The crash happened just after 12 p.m. The interstate was closed until 11 p.m. At one point, there was a 10-mile backup in each direction, said the Arizona Department of Transportation.
"It's very different than what we think of during the monsoon. In this case, a steady southwest wind created channels of dense, blowing dust. Unfortunately, one of those localized channels of dust ended up over a busy Arizona interstate," Chief Meteorologist Chris Dunn said.
Weather Alerts Interactive Map Arizona Web Cams Receive Weather Alerts via Email Follow Arizona Weather on Twitter Like Arizona Weather on Facebook Send Weather Photos & Videos to CBS 5 SLIDESHOW:More >
Weather Alerts Interactive Map Arizona Web Cams Receive Weather Alerts via Email Follow Arizona Weather on Twitter Like Arizona Weather on Facebook Send Weather Photos & Videos to CBS 5More >