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Hundreds of firefighters from around the country joined with thousands of locals in Prescott, Arizona, today. They were there to pay tribute to 19 firefighters lost in last week's blaze. Firefighter Darrell Willis addressed the crowd in his work clothes.
DARRELL WILLIS: Because I'm honoring the Hotshots, the Granite Mountain Hotshots, I know that's the way they wanted me dressed - with Yarnell dirt on my boots and the same uniform I was wearing the night that they perished, June 30th.
CORNISH: The Yarnell Hill fire was the deadliest wildland fire in 80 years. A team of people from multiple agencies is working hard to figure out what went wrong, and as NPR's Nathan Rott reports, they're not the only ones trying.
NATHAN ROTT, BYLINE: Bill Gabbert was at his South Dakota home when he heard that a crew of firefighters had been overtaken by flames in Arizona. And at first, he didn't believe it.
BILL GABBERT: That has to be a mistake. We just don't do that anymore. We just don't kill large numbers of firefighters all at the same time. I thought we had moved beyond that.
ROTT: Gabbert was a wildland firefighter for 20 years. He now runs the website Wildfire Today, a go-to site for wildland firefighters across the country. He's in Prescott for today's memorial because he says firefighting's a family. And as someone who writes about fire safety and lessons learned, he knows how big of a deal this is for the firefighting community.
GABBERT: This is something we're going to be talking about for decades.
ROTT: When something goes wrong in wildland fire, it's talked about. When something goes this wrong in wildland fire, policies are changed and books are written.
The only fire that Gabbert can think of that compares to this is the South Canyon Fire in 1994. There, 14 elite firefighters died on Colorado's Storm King Mountain. A cold front passed over the fire area, causing high winds and unexpected fire activity and it caught the firefighters completely off guard.
Carl Seielstad knew some of those firefighters. He's a professor at the University of Montana and a former smokejumper and hotshot. He says that South Canyon helped define modern firefighting.
CARL SEIELSTAD: So that's where lookouts, communications, escape routes and safety zones - LCES - came from.
ROTT: And wildland firefighters hear those - lookouts, communications, escape routes, safety zones - a lot. Many even have LCES pasted on their helmets.
SEIELSTAD: If all of those things are in place, the firefighter should be relatively safe.
ROTT: In the aftermath of the Yarnell Hill Fire, that's what firefighters like Gabbert and Seielstad are looking at. It's also what the multi-agency investigation team is looking at. And judging from the things that we know, some of those were in place.
We know that Brendan McDonough, the sole survivor of the Granite Mountain Hotshots, was posted as a lookout on a nearby ridgeline and that he warned the team that the fire had changed direction. We know that they had communications with other firefighting units because a helicopter heard their call for help but couldn't see them in the smoke. And we know that they had an escape route and safety zone. They were to go to a nearby ranch and ride things out if something went wrong. And, of course, it did. Carl Seielstad has seen plenty of fire and he says that happens.
SEIELSTAD: You know, all firefighters game out the worst-case scenarios, but you don't really know what the worst case is, I don't think, unless you actually have seen it because fire always surprises me. I have seen things in my career in fire that are almost special effects-like, that you see and you think, I don't even see that it's possible that fire could do something like that.
ROTT: And judging from the other things we know, that's what happened on Yarnell Hill. At 11 a.m. on June 30th, the fire was between 800 to 1,000 acres in size. The Granite Mountain Hotshots were texting their friends and wives.
At around 4 p.m., a thunderstorm came over the fire, generating winds of up to 40 miles an hour. It flipped the fire's direction 180 degrees and pushed it towards the firefighters at up to 24 miles an hour, cutting off their escape route.
SEIELSTAD: Fundamentally, in those kinds of events, the change just happens almost instantaneously. There isn't like a cue that makes you think, OK, here it comes. It just - it happens.
ROTT: Investigators will still look to see if anything was missed. They will look at where the fire was burning and if the approaching thunderstorm was communicated to the crew because it was predicted.
They will try to learn why the crew appears to have deployed their fire shelters in a basin, which most firefighters would say is the worst possible place. The interagency investigation team is expected to give a full report in September. But much of what happened on the Yarnell Hill Fire that day may never be known. Nathan Rott, NPR News.
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This is ALL THINGS CONSIDERED from NPR News. Transcript provided by NPR, Copyright NPR.