Another major dust storm struck near Picacho Peak Tuesday afternoon, dropping visibility to zero and causing the largest series of chain-reaction wrecks this year on Interstate 10.
At least one person, a man in his 70s, was killed and about 15 more were injured in two crashes that involved 16 vehicles on westbound I-10. The crashes occurred shortly before 12:30 p.m., state Department of Public Safety officials said.
The deceased man's wife was critically injured, and another person from a different vehicle had life-threatening injuries, said Bart Graves, a DPS spokesman.
A third chain-reaction crash involving eight vehicles happened about 1:45 p.m. in the eastbound lanes of I-10 near McCartney Road. Two people in that wreck were critically injured, Graves said.
Yet another dust-storm-related crash occurred at about 3:50 p.m. It involved two tractor-trailer rigs and a small car farther north on I-10 near Chandler, he said. Two people in the car suffered serious injuries.
The dust was so thick officials could not use helicopters to transport the seriously injured, with most being taken by ambulance to hospitals in Tucson. Both directions of travel on I-10 were closed for several hours.
Several Tucson-area public-safety agencies were dispatched to the wrecks, including Northwest Fire, Avra Valley Fire and Rural/Metro Fire.
"It looked like a war zone," Patrick Calhoun, one of the first rescuers at the scene, told The Associated Press. "This has been one of the worst pileups we've had on the I-10."
Calhoun, with the Avra Valley Fire District, said the man who died was in the passenger seat. Their car slammed into the back of a tractor-trailer rig and was lodged underneath, killing the man and critically injuring the woman.
Calhoun said it took 45 minutes to hook up winches to the vehicle, pull it out and then cut the woman out of the car.
Winds were between 20 and 30 mph in the area near Picacho Peak but may have reached up to 40 mph, said Craig Shoemaker, a meteorologist with the National Weather Service. He said the dust storm happened in a localized area likely due to the amount of recently tilled or loose soil in farmland near Picacho Peak.
Along with the strong winds, rainstorms that passed over the area created virga or "precipitation that evaporates before it hits the surface," he said. Virga can contribute to stronger winds, Shoemaker said.
The weather service predicted another storm system will move through the area Thursday, which could be even more dangerous.
"If we get the same kind of setup that we had today (Tuesday), the sustained winds look to be stronger with that system than they were (Tuesday) afternoon," Shoemaker said.
Frequent dust storms have made the stretch of highway between Red Rock and Picacho Peak treacherous in the last couple of months.
• On Sept. 27, thirteen people were injured in a seven-vehicle wreck on I-10 near Picacho Peak. Five people were taken to hospitals for treatment.
• In late August an infant was killed and two other people were injured when a dust storm crossed I-10 near Red Rock, just south of Picacho Peak, causing a 10-vehicle accident.
Crashes repeatedly occur on two stretches of Interstate 10 between Tucson and Phoenix - from just south of the Gila River to the town of Picacho (mileposts 175-215) and in a stretch north of Red Rock.
In a Star report about the dust storms last month, agriculture was identified as a concern.
"Agriculture is a huge factor in dust pollution, and we still have the fox guarding the henhouse and we're still doing very little," said Sierra Club lobbyist Sandy Bahr.
Farmers can be cited by air-quality regulators for allowing dust to escape their fields and feedlots, but regulation of farming practices was given to the state Department of Agriculture by the Legislature.
State air quality director Eric Massey said the state does require farmers and ranchers to keep a record of their "best management practices" in areas that are ordered by the EPA to limit dust pollution, a menu of choices ranging from using crops that require fewer passes of farm equipment in the fields to refraining from tilling when the wind is blowing at 25 mph or higher.
Most farmers employ best practices even without regulation, said Rusty Van Leuven, who heads a state Agriculture Department program that helps farmers voluntarily comply with the rules.
DPS officials recommend that motorists caught in dust storms slow down, exit the highway at the nearest offramp and get as far away from the road as possible. Motorists should turn off the car's lights and remain in the vehicle with seat belts fastened.
Did You Know?
Dust storms happen often in the huge bowl between Tucson and Phoenix, where the terrain is fairly flat and dust sources are plentiful.
When a storm starts north of Tucson and hits Phoenix, Pinal County's degraded bowl is the likely contributor, with its vast acreage of tilled land, grazed desert, feedlots, land cleared for subdivisions, silty washes and river bottoms, ATV trails, sand-and-gravel operations and dirt roads, experts told the Arizona Daily Star last month.
Reporters Jamar Younger, Tom Beal and The Associated Press contributed to this report. Contact reporter Veronica Cruz at firstname.lastname@example.org or 573-4224.