How do state agencies decide when to close a portion of a highway?

What exactly does it it take to shut down a portion of a highway during severe weather? What state agency is responsible?

The answer: New Mexico State Police.

“(If wind gusts) go from twenty miles an hour to thirty or forty, then we’ll make the arrangements when visibility gets low,” said Officer Carl Christiansen, a spokesman for New Mexico State Police. “We’ll make the appropriate detours and shut down the interstate.”

Even though NMSP officers make the final call, it’s a collaborative effort between multiple agencies, including the National Weather Service and the New Mexico Department of Transportation, as well as local Sheriffs’ departments.

If a storm is close enough to the border, New Mexico will rope in agencies from other states, like the Arizona Department of Transportation or the Arizona Department of Public Safety.

“On Monday, that happened so abruptly there was no forewarning,” Christiansen said.

Christiansen said Monday’s deadly dust storm along Interstate 10 came far too early for state agencies to act promptly.

“It happened very quickly,” Christiansen said. “Within five to ten minutes it went from ‘visibility was fine’ to ‘no visibility.'”

There is, however, no official or written procedure for shutting down a road, because each situation is fluid.

“Well it’s free-flowing on a normal basis,” Christiansen said. “So it’s up to the officers when they feel it’s unsafe.”

Several state agencies and organizations met in February 2016 to discuss how to prevent future accidents along highways during dust storms.

The meeting was held near Gila, N.M., less than one hundred miles north of Monday’s crash.

Officials with the New Mexico Department of Transportation, the Arizona Department of Transportation, the National Weather Service, New Mexico State Police and the Bureau of Land Management attended the meeting.

The majority of dust storms appear to be located in the southern and southeast parts of the state, according to a graphic produced by the New Mexico Department of Transportation.

While there are posted signs along the highway, and alerts on the radio, Christiansen confirmed that the state is planning to do more in the near future.

“We’re looking at branching out into social media and utilizing that resource,” Christiansen said.