Relatório do Acidente ocorrido no Incêndio Florestal de Yarnel Hill

• If they descended from the ridge, they would maintain sight of the Ranch.
• Fire was still heading east-southeast toward Yarnell.
• Smoke column was predominantly going east-southeast with clear air south of the fire.
As the crew reached the descent point at about 1620, they likely knew or perceived:
• Below the two-track road, they could see the following:
o A box canyon
o Pockets of heavy brush mixed with rock-strewn hillsides with some large boulders
o Washes and game trails and areas of lesser vegetation they could tie together and
make a path
o Steep descent initially and then flattening terrain
• The direct path to the Ranch appeared shorter, and potentially faster, than continuing to
follow the two-track road around the rim of the box canyon.
• The weather in the update had not materialized at their location and the update was
about 50 minutes old.
WHAT THEY LIKELY DID NOT KNOW AT POINT B:
• A large thunderstorm over 15 miles to the north and northeast was creating an outflow
boundary that was going to cause a wind direction shift and increase in velocity,
resulting in an increase in fire spread rates and a directional change to the south.
• This outflow boundary had reached the north end of the fire at 1618 according to
Federal Aviation Administration (FAA) radar.
• The crew’s possible rate of travel would be less than half of what it had been to this
point due to lack of a defined trail, heavy vegetation, and rocky terrain between the
crew and the Ranch.
• Boulder Springs Ranch was further away than it appeared.
• Other resources did not understand fully when the Granite Mountain IHC attempted to
communicate their movement.
FOUR COURSES OF ACTION AVAILABLE AT POINT B, AROUND 1620:
Course of Action B1: Descend here; move toward the Ranch through the box canyon
• Appeared to be the most direct, shortest, and fastest path to the Ranch.
• The fastest route was desirable because of the perceived threat to the community of
Yarnell.
Yarnell Hill Fire Serious Accident Investigation 38