A dust storm warning was issued after a 19-vehicle pileup on Interstate 10 in the Picacho Peak area Tuesday because there is no system in place to detect isolated, low-lying storms, a National Weather Service meteorologist said.
Even if a severe dust alert was issued before a storm, “it would be a major challenge to shut down I-10 between Tucson and Phoenix,” to try to prevent accidents, said a spokesman with the Department of Public Safety.
The dust warning was issued at 12:49 p.m., said Glenn Lader, a meteorologist with the National Weather Service in Tucson.
That was about 20 minutes after the storm passed through the Picacho Peak area. The crashes were reported at 12:11 p.m. just after the onset of the dust storm that blew through around noon and lasted until 12:30 p.m., said Bart Graves, a DPS spokesman.
Three people were killed and 12 others were hurt with critical to serious injuries in the chain-reaction crashes that closed the interstate into Tuesday night.
Killed in the pileup were: Gordon Lee Smith, 76, of Mead, Wash.; David D. Bechtel, 51, of Milton, Iowa; and Lenny Lubers, 46, of Phoenix.
A second two-vehicle crash occurred within the eastbound traffic lanes of I-10 that involved minor injuries and a commercial vehicle.
The southwest side of I-10 at milepost 214, where blowing dust caused Tuesday’s massive crash, is the “pinnacle of where we’ve seen problems for a decade,” said Don Gabrielson, director of Air Quality for Pinal County.
Gabrielson said Arizona Department of Transportation statistics record more severe dust-related crashes at the spot than anywhere else along the interstate in Arizona.
The land south and west of the location is “degraded desert” cut by washes where “desert shrub silts up on the lee of whatever vegetation exists. It builds up a reservoir of material. In a gust, all that material explodes,” he said.
Gabrielson said he’s been to the site when the barbed-wire fence along the frontage road was buried up to the second wire in silt.
The land, some privately owned and some state-owned, is not farmed and does not seem to be a place where off-road vehicles travel, Gabrielson said.
There wasn’t a great deal of wind in the area Tuesday, said Mike Leuthold of the University of Arizona department of atmospheric sciences. Leuthold said nearby wind gauges turned up no gusts stronger than 23 mph, which usually isn’t enough to create a dust storm.
Graves said gusts were 29 mph during the storm.
“Some sections of Interstate 10 produce dust at relatively low wind speeds,” Leuthold said. “That kind of thing is almost impossible to mitigate.”
Lader, of the weather service, said the type of dust storm that kicked up Tuesday was “very localized and low-lying, making it difficult to observe.”
“We don’t have weather instrumentation in the area, and that type of storm cannot be detected on satellite or radar,” Lader said.
He said no weather spotters reported problems in the area, and the weather service found out about the storm through the DPS and state Department of Transportation officials.
On Sunday there was a weather forecast for blowing dust in the area, Lader said. It did not happen Monday, but it happened Tuesday. “Some days you can get the dust, and other days you may not,” he said.
“The summer haboob events are totally different because it is winds from thunderstorms creating huge walls of dust that can be detected on radar,” Lader explained.
The closest radar is out of Phoenix, and it picks up storms 2,500 feet above the ground and higher, Lader said. He said Tuesday’s storm was “very isolated and probably no more than 500 feet to 1,000 feet above the ground.”
He said the weather service has had workshops with the DPS, ADOT and the state and county departments of environmental quality to try to address the issue.
ADOT spokesman Dustin Krugel said a $600,000 pilot project was launched in 2011 to study a weather warning system, including dust, rain, snow and windstorms.
The system is set up in a dust-prone area off I-10 near Willcox. It includes monitoring stations, cameras, visibility and wind measuring instruments within a 10-mile area, Krugel said.
“The goal is to deliver real-time safety warnings to drivers and alert maintenance ADOT crews to adverse weather conditions,” he said. The system uses a highway advisory radio, which issues an AM frequency to broadcast the road conditions to drivers.
Flashing signs off the highway show a message telling motorists to tune into a specific radio channel when a weather warning is issued, Krugel said.
“We still have to work out kinks and do a study with data to show if it is effective. This will take a couple more years,” Krugel said.
“The pilot program has a potential of showing promise, and if it is expanded to additional dust-prone areas, it would help out in the Casa Grande and Picacho Peak areas, Lader said.
ADOT has 170 overhead message boards on highways in the state, mostly in urban areas that warn motorists about road conditions. Next year, Krugel said, more message boards and cameras are expected to be added to the I-10 corridor between Tucson and Phoenix.
Graves, of the DPS, said trying to restrict travel on I-10 because of approaching severe weather would be difficult.
“It is one of the most heavily traveled corridors in the state,” he said. He said the DPS would rather work with the media, the weather service and the state Transportation Department to send alerts to motorists.
“Officers on duty are told of the alerts, and they start monitoring traffic by turning on their lights, and then motorists start slowing down, and some pull to the side of the road and turn off their lights.
“But you still have some who will power through the storm. There is no way of predicting human nature. We still have to continue educating the public through news stories, public-service announcements and through social media,” Graves said.