On August 8, 2016, a lightning strike ignited a small fire on the edge of Yellowstone National Park near the community of West Yellowstone. Most fires in the park never burn more than about a quarter-acre, but the Maple Fire would go on to burn over 45,000. It was the largest fire in the park since the historic fires of 1988.

JOHN CATALDO – Is there anything as wild, beautiful, and important as fire in Yellowstone?I’m not sure.

Narrator - This is John Cataldo, the Fire Management Officer for Yellowstone National Park. Which means it’s his job to manage everything having to do with fire in the Park.

JOHN CATALDO - It seems like we're always at work in the summer and somehow at least my impression is that 80% of the fires we get are when I'm at home eating dinner. So, fires and telemarketers are who finds me a seven o'clock at night, at my home.

Narrator - And on the night of August 8th, 2016, John got that kind of call. An aircraft full of smokejumpers flying over Yellowstone National Park spotted a new fire. The jumper aircraft circled the fire, collected a GPS location, and then they texted John’s crew.

JOHN CATALDO - Yeah, sent us a photo. I mean, that's the information age, right? So we had a report we had a photo from the aircraft of the fire. It gave us a basic idea of the fuels that were in the immediate vicinity of it. It was about ¼-acre and that’s generally speaking, what I have to work with in a remote environment .

Narrator - The fire was located on the far western side of the Park, just about six miles east of the town of West Yellowstone. So John did what he often does. He notified the Deputy Superintendent and the Chief Ranger, and then he called Yellowstone’s fire ecologist to run the nearest weather station for wind data. And then very early the next morning John poured over maps of the area and all the collected data on the new fire, and he had this really big decision to make. To put the fire out or to let it burn.

JOHN CATALDO - Essentially it comes down to do we think this is a good fire or a bad fire?

Narrator - And with this fire, the Maple Fire, being so close to the town of West Yellowstone was a huge consideration.

JOHN CATALDO - A lot goes into it, but at the end of the day it's a real estate game, and it's location, location, location.

Narrator - But the fire had two things going for it being a good fire. First, 95% of the winds in recorded history at the closest weather station had blown from the west or southwest. Directions that would push the flames farther away from the community of West Yellowstone and deeper into the park backcountry. So while winds were likely to push the fire in the other direction, John knew that the proximity to West Yellowstone would have a lot of people interested in this fire.

JOHN CATALDO - Well, you want to provide insurance, so 95%'s pretty high number, right? If I gave you 95% odds on a blackjack hand, you'd probably push your house payment out there, but 5% is a pretty substantial risk if you're the one living in the community on the 5% end of that.

Narrator - But the second thing that helped managers feel like the Maple fire might be a good fire? It was that the fire had started in an area that had burned way back in the 1988 fire season.

JOHN CATALDO - If you were to play word association with anyone in West Yellowstone since 1988, and you say "'88," the first thing they're going to say is "fire." There's no other word.

Narrator - 1988 was a particularly dry summer in Yellowstone. When lightning storms hit the Park in August large fires sprouted everywhere. Fires so big, tens of thousands of fire fighters were mobilized to fight them. National news covered the events nightly.

(Roy Renkin): In recorded history, we had not been that dry…

Narrator - That's Roy Renkin, a Yellowstone Vegetation Management Specialist who has been looking at fire’s effects in the Park for almost 40 years. Roy saw the 1988 fires firsthand.

ROY RENKIN - …and as a consequence these fires were large with these big flaming fronts… and they were moving and with dramatic spread rates. You could up measure them in multiple kilometers per hour

and you fly along at the head of some of these fires and you would think that you know the fire is moving faster than the aircraft. Its pretty dramatic stuff.

Narrator - And back in 1988 there was a lot of pressure to put these fires out. For 100 years the majority of land managers had been putting out almost every every wildfire they could immediately. And it was part of greater American culture to automatically think of forest fires as a threat. And because fires hadn’t burned in Yellowstone for hundreds of years, the forests were thick with fuels to burn. A whole lot of fuel in a really dry year. The fires got big enough that their smoke blew all the way from Wyoming to Chicago. Media scrutiny was intense. So much so that President Ronald Reagan weighed in sending in the military to fight the fires.

ROY RENKIN - , it was a quarter of an inch of snow on September eleventh of 1988 that did what , you know, ten thousand firefighters, 220 different aircraft, you know so many miles of fire line you know, couldn’t do that put a halt to the eighty-eight fires. A quarter of an inch of snow.

ROY REKIN - but what people don't realize is that these fires, just like the sun comes up in the day and the moon comes up at night, western forests burn.

Narrator - By the end of the ’88 fire season nearly 800,000 acres in Yellowstone had burned. One third of the entire Park. That much area burning in a protected ecosystem created a unique place to study the effects of big fires on the landscape. Scientists noted a series of benefits to that ecosystem after the 88 fires, demonstrating a value to letting naturally-caused fires burn. Chief amongst them, the pattern of areas burned in different years created a mosaic of forest ages with a diversity of plants present. And this diversity of habitats was really good for most animals. Also, since there was less fuel where previous fires burned through, the mosaic of past fires helped provide a really great boundary to stop new forest fires from becoming large.

Narrator - Which brings us back to the Maple Fire starting in 2016 and the decision John Cataldo had to make… to let the Maple Fire burn or to put it out.

JOHN CATALDO - Well, fire is the lifeblood of the Yellowstone ecosystem, so if we exclude fire, essentially this ecosystem as we know it dies. It would grow decadent and expire. Fire here is essentially the ecological reset button, and our job is to keep as much of it on the landscape as we can safely do, but it's complicated.

JOHN CATALDO - we're just facilitating the conversation between fire and humans essentially. This park will never have a fire problem. Essentially what it has is 2000 structures and four million visitors that we need to work our tails off during fire season to keep separated from the fire that we need on the landscape, and that's the challenge. It's 2000 structures and four million visitors.

Narrator - And so here was this new fire, the Maple Fire, started by a lightning strike in the middle of a big area that had burned in 1988. And since 1988, due to that mosaic of forest ages, fires starting in the 88 burn area hadn’t really gone anywhere. And so John and his team decided to let the fire burn thinking it would just kind of sputter out.

JOHN CATALDO - The eyes were wide open as that fire persisted and became two acres, and then five, and then maybe a week or so into the fire being on the landscape it was in the hundreds and we knew that we were going to have a substantial fire until the snow flew.

Narrator - And for everyone who studies fire in Yellowstone, this fact, a fire growing large in the 88 burn scar, was something odd.

JOHN CATALDO – Generally speaking, up to that point, the ’88 fire scar in a lot of ways was almost viewed as asbestos. It was a great natural barrier to fire spread so for a lot of our fires since ’88 we were using that fire scar as a boundary.

Narrator - But not anymore.

Narrator - A tall column of smoke formed as the fire grew. A huge plume that could be seen from far away. Just six miles away in West Yellowstone, residents started to get nervous about their proximity to the growing fire.

JOHN CATALDO - Things were tense in West Yellowstone, particularly in the beginning of the life of the Maple Fire. I joke about it now, but some of those first public meetings were 200 pitchforks and tiki torches out there in the crowd.

Narrator - A dozen fire public information officers were brought in to organize daily public meetings to make sure the most current information and management plan was getting out. In total over 400 firefighters were assigned to manage the blaze.

JOHN CATALDO - To be honest, the strategy that was eventually employed by the incident management team was something we'd sketched out on a cocktail napkin on about the third day of that fire burning.

Narrator - The main plan was to control the fire’s edge near West Yellowstone and let the fire keep burning slowly, like lava, eastward. To do so, firefighters would allow the fire to chew it’s way toward the the Madison River on the west side. Then, using the river as a boundary, they’d employ a tactic called a backfire—starting a new fire on the edge of the river—and as the Maple Fire sucked in air to feed its flames, it would pull the fire-fighter ignited burn eastward. The two fires would then join leaving no more fuel on the western flank for the Maple Fire to carry into. And it worked, but managers were still surprised that the fire was burning in the ’88 burn scar at all.

JOHN CATALDO - We suspect it was the extreme dryness of the large logs that were dead and downed and underneath. For a lot of the Maple Fire area, the fire wasn't carrying through the tops of the vegetation. It was actually first burning underneath through the heavy woody debris, and it would scorch and dry out things enough above it that they would eventually become consumed after the main fire had passed.

Narrator - But other than burning in the ’88 burn scar the Maple Fire did what many people thought it would do. For the most part it kept slowly burning east while firefighters watched over it. And eventually, much like the ‘88 fire season, snow and rain in September put the Maple fire out. All of which was what fire managers had planned for.

JOHN CATALDO - Now the community of West Yellowstone has a 45,000 acre fire scar on one side of it that is going to insulate it from any fires that we may want to control and can't that originate in that part of the park.

Narrator - And both John and Roy say that warmer overall temperatures associated with climate change are likely to complicate fire on the landscape. With predictions of fire becoming more likely in the park, the overall makeup of forests will likely change too. Some tree species, such as lodgepole pine are expected to decline, while others like Douglas fir become more prevalent. And this changing environment in Yellowstone poses new challenges that have fire managers like John looking toward the future.

JOHN CATALDO - Essentially from where I'm sitting, because I'm one of the ones making the decision whether a fire should be encouraged to be on the landscape or suppressed, is I just keep defaulting to fire is what this ecosystem needs. Ultimately if climate change dictates that the ecosystem looks differently or functions differently, it's going to be with fire in it. We're not going to start going backwards and putting out fires out of fear of climate change.

Narrator - And John says that seeing the big picture is the main reason not to go backwards.

Like the expression goes, "You trust the process." What we're doing is managing processes. We're not managing species. We're not even just managing plant communities. We're managing entire processes that we don't completely, and nor will ever completely understand all of the interrelationships of what fire brings to that. So trusting the process.

Narrator - For Yellowstone National Park, I’m Scott Christy.