PLACER COUNTY, Calif. (KTXL) — Burning a total of 396,340 acres in a span of eight years, these three fires threatened communities and lives but represent an evolution in firefighting.

FOX40 spoke with CAL FIRE Nevada-Yuba-Placer Unit (NEU) Chief Brian Estes, who served with CAL FIRE on all three of these fire, about the similarities and differences between the Caldor, King and Mosquito Fires’ weather patterns, terrain and firefighting tactics.

The King Fire burned from Sept. 13, 2014 to Oct. 9, 2014 across 97,717 acres of El Dorado County, near Pollock Pines.

The Caldor Fire started on Aug. 14, 2021 and burned 221, 835 acres from Pleasant Valley to South Lake Tahoe until it was stopped on Oct. 21, 2021.

The Mosquito Fire, which started on Sept. 6, 2022, has burned 76,788 acres and is at 90% containment as of Oct. 4.

“Really you are going to define all of your challenges on a fire by three things; fuels, weather and topography,” Estes said. “If you align all three of those you got a perfect storm.”

Weather Patterns

These three fires each ignited during a time of year where rising temperatures caused low relative humidity, decreased rainfall allowed for dry fuel and seasonal winds breathed life into the flames.

Estes said that even though the King Fire started in 2014, on the cusp of the drought, the build-up of dry fuel beds over the years allowed for a fast and aggressive spread like the Caldor and Mosquito Fire.

“The other two (Mosquito and Caldor) had that component (heavy fuel loads) plus tree mortality, beetle kill, heavy undergrowth in the national forest system and then of course the effects of the drought.”  

The King Fire and Mosquito Fire would both see several inches of rain slow down the fires and help fire crews gain containment around the fires.

On Sept. 25, 2014, 2 inches of rain would fall on the King Fire and on Sept. 17 and Sept. 18 rain would slow the spread of the Mosquito Fire, allowing crews to gain better containment on the eastern edge of the fire.

Estes said that the Caldor Fire was hit by some rain but not enough to slow the blaze and keep it from getting to unburned forestlands.

Fuel Loads and Fire Mitigation Efforts

Fuel loads can be built-up pine needles, dead standing trees, dry brush and any other type of vegetation that will easily burn in a fire.

Mitigation is the act of reducing and eliminating fuel loads by creating defensible spaces around homes, removing ground cover, masticating dry vegetation and clearing low-hanging limbs to reduce the chances of the fire making its way into the overstory.

Heavy fuel loads played into the large scales of each of these fires, but the creation and build up of these incredibly flammable areas differ slightly.

Estes describes the area in which the Mosquito Fire burned as “detrimental” due to the lack of large-scale fires in the area for several decades.

“Where we have areas with unrecorded fire history that can be really detrimental because there is unburned fuel, there is a lot of dead and decadent fuel,” Estes said.

The Caldor Fire was furnished by dead standing timber from bark beetles spurred on by the drought.

As the fire continued burning dense timber lines along Highway 50, it found an area of unburned forest on the eastern side of Echo Summit and into South Lake Tahoe.

Estes said that the area in which the Caldor Fire burned had a long and active history of fire, but the last major fire in the area was the Wrights Fire in 1981, allowing time for regrowth.

Because the current series of droughts did not begin until 2016, it did not impact forest health and influence the King Fire like the drought did for Mosquito and Caldor.

A large buildup in fuel loads, especially along the forest floor, in national forest lands allowed the King Fire to spread quickly and burn intensely. Like the Mosquito Fire, the area had also not seen major fires in decades.

Although CAL FIRE does not manage forests or fire, as they are responsible for private lands, according to Estes, the agency has begun conducting fuel load reduction work and seeing results from it.

“I will say in the last 10 years we have had to take a much more broad stroke approach to that and we have gotten more involved in landscape level fuel reduction efforts,” Estes said. “Still with the protection of communities as our number one goal.”

Estes said that fuel reduction efforts were made in the Foresthill and Todd Valley area before the Mosquito Fire that aided in the protection of both communities.

These projects are a never-ending effort though and returning the forest to what it was a century ago is a nearly unattainable feat, according to Estes.

“The minute you disturb the soil it starts growing again,” Estes said. “You can put a lot of work into something and just about the time you are done you have to start all over again.”  

Inaccessible and challenging terrain

Deep canyons with steep walls carved by major rivers define much of the foothills landscape where these three fires burned and were able to escape the reach of hand crews.

CAL FIRE describes these areas as river drainages. The defining drainages in the areas of these fires are the multiple forks of the American River, the Rubicon and the Cosumnes River.

“Each of those drainages just presents an opportunity for these fires once they get established in those drainages they are very very difficult to fight,” Estes said.

When the King Fire made it into the Rubicon and the Mosquito made it into the North Fork of the American they saw their largest single-day growths.

Hand crews can have an incredibly hard time accessing these areas in order to cut containment lines during the fire. It is also difficult for them to access during fuel mitigation operations, creating heavy fuel loads in these drainage systems.

During the Mosquito Fire update on Saturday, operational leaders shared that containment lines would not be made in the area of the North Fork of the Middle Fork of the American River and the Rubicon River due to the challenging terrain.

Terrain also can help in slowing a fire as well, according to Estes.

As the King Fire made its way north it ran into a granite wall that did not stop it but did slow its spread. The Mosquito Fire would have also hit a similar granite wall if early rains had not already slowed it down.

The area of the Caldor fire has many smaller drainage systems throughout the main area of the fire, but it was also flanked to the south by the Middle Fork of the Cosumnes River and to the north by the South Fork of the American River.

Air Attack resources

From WWII-era aircraft flying in the daytime to operations Blackhawk helicopters aiding crews in nighttime operations, Estes has seen a massive evolution in CAL FIRE air operations.

Estes said that the change in air operations between the King Fire and Mosquito Fire showed a substantial shift in what was possible even less than a decade apart.

“We had every heavy jet air tanker or VLAT (Very Large Airtanker) in the Western United States, all four of them, assigned to Foresthill that day,” Estes said. “If you compare that to 2014, we didn’t have any VLAT’s, they were under development.”

These heavy tankers include the DC-10, capable of carrying 9,400 gallons of fire retardant and the Boeing 747, capable of carrying 17,500 gallons of fire retardant.

When these fires burn into those drainage systems, air support is sometimes the only way that a fire can be slowed and eventually contained.

During the Mosquito Fire, an unprecedented 16 tankers were working on the day the flames made a run towards Foresthill.

Accurate air drops and containment lines made by hand crews held the fire back from burning down the threatened community.

Improved infrastructure at McClellan Air Base has also improved the capabilities of these incredibly large aircraft.

Estes said that on a busy year the Grass Valley Air Attack Base will pump 500,000 gallons of retardant into their tankers. McClellan on an average day pump 200,000 gallons of retardant and on a busy day can pump 500,000 gallons of retardant.

2022 was also the first year that CAL FIRE began using their Sikorsky S70i Hawk for fire nighttime operations and the Mosquito Fire was the third fire of the year to benefit from this new air capability.

Photo by Matthew Nobert

“The crews were firing and constructing line below Worton’s Market, getting ready to turn and take it all the way to the river that night and as the sun set I heard are Blackhawk coming on scene at night on goggles and supported that crew all night into that canyon,” Estes said. “By morning they were at the river.” 

While CAL FIRE has always had a large air wing, according to Estes, these newly acquired aircraft have changed fire fighting tactics and capabilities, but also what people look to see when a fire does start.

“It is no longer something out of the ordinary, it is just something that is expected,” Estes said. “So it has been tremendous.”


In less than a decade these fires destroyed several thousands of acres of forestland, threatened communities and lives, set records, but also saw an evolution in fire fighting tactics and mitigation efforts.

Even with these fires creating large burn scars across a concentrated area of wildlands, Estes still believes that this section of the foothills could see another large-scale fire in the coming years.

“I think it is very possible that we could see that trend continue in the higher elevations,” Estes said. “The forest service has a lot of challenges with drought-stressed fuels and tree mortality from the beetle kill because of the drought.”

Estes said that the areas many river drainage systems loaded with built-up fuel loads pose the greatest threat to the region and that human activity in these areas will always provide a source of ignition.

The strong public support for fuel load reductions on private lands is reassuring to Estes, but he still holds that CAL FIRE’s stratagem of fast and aggressive suppression is still a key part of saving people and property.

“The fuel reduction is a big part of it, but at the end of the day there still has to be an airplane that drops retardant, a fire engine that pulls hose, a bulldozer that pushes dirt and hand crews that cut lines,” Estes said.