PRESCOTT, ARIZ. — Fire crews battling a wildfire should identify escape routes and safe zones. They should pay close attention to the weather forecast. And they should post lookouts.

Those are standards the government follows to protect firefighters, which were toughened after a wildfire tragedy in Colorado nearly two decades ago. On Tuesday, investigators from around the U.S. were arriving in Arizona to examine whether 19 highly trained firefighters who perished over the weekend heeded those rules or ignored them and paid with their lives.

In the nation’s biggest loss of firefighters since 9/11, violent wind gusts Sunday turned what was believed to be a relatively manageable lightning-ignited forest fire in Yarnell into a death trap that left no escape for the team of Hotshots willing to go to the hottest part of the blaze.

The tragedy raised questions of whether the crew should have been pulled out much earlier and whether all the usual precautions would have made any difference in the face of triple-digit temperatures, erratic winds and tinderbox conditions that caused the fire to explode.

In 1994, 14 firefighters died on Colorado’s Storm King Mountain, and investigators afterward found numerous errors in the way the blaze was fought. In the Storm King tragedy, a rapid change in weather sent winds raging, creating 100-foot tongues of flame. Firefighters were unable to escape, as a wall of fire raced up a hillside.

The U.S. Forest Service revised its firefighting policies as a result of the blaze. “The reforms after Storm King were collectively intended to prevent that from happening again, which was mass entrapment of an entire Hotshot crew,” said Lloyd Burton, professor of environmental law and policy at the University of Colorado. “There are so many striking parallels between this tragedy and what happened on Storm King in 1994, it’s almost haunting.”

Those changes included policies that say no firefighters should be deployed unless they have a safe place to retreat. They must also be continuously informed of changing weather.

The Hotshot team from Prescott entered the smoky wilderness over the weekend with backpacks, chain saws and other heavy gear to remove brush and trees and deprive the flames of fuel.

But the blaze grew from 200 acres to about 2,000 in a matter of hours as “the wind kicked up to 40 to 50 mph gusts and it blew east, south, west — every which way,” said Prescott City Councilman Len Scamardo.