Nearly two dozen vehicles, including a passenger bus and 12 tractor-trailers, were involved in fiery crashes on both sides of Interstate 10 some 45 miles west of Phoenix.
A dust storm hit the Phoenix area at about the time of the accidents Wednesday night and officials said the chain-reaction crashes were weather-related.
Authorities said it appeared a passenger vehicle had stopped in the middle of the road, starting the series of crashes.
``This dust storm came in pretty quick,'' said Officer Erick Anspach of the Arizona Department of Public Safety. ``Some drivers reported having only a second or two until impact.''
Both lanes of Interstate 10 were initially blocked and emergency crews initially had a tough time reaching the crash scene, according to the DPS.
``We could see nothing but dust and smoke'' upon arriving, said firefighter Nate Ryan.
Ambulances and numerous medical helicopters transported victims to several Phoenix-area hospitals, DPS spokesman Steve Volden said.
The injuries ranged from cuts and scrapes to life-threatening injuries.
Several of the vehicles caught fire after the collisions, Volden said.
Early Thursday, officers could be seen walking on the wreckage, illuminating the vehicles with flashlights as they looked for victims.
A line of crashed vehicles extended for about a quarter of a mile. One big truck had its nose pushed under the trailer of another. A skeletal frame was all that was left of another truck.
One of the dead victims was in a car that had become wedged under a truck, said Volden. The second fatality was a truck driver.
The passenger was scorched on the tail end but seemed largely intact otherwise.
Volden said 24 people were on the bus, including two drivers. Officers didn't know how many passengers were injured.
