2023 Week of Remembrance Day 2

Stockyard Fire (Michigan) – July 1, 1988

Today’s topic is dedicated to all of Michigan's fallen firefighters.
May we never stop learning.

The Stockyard Fire entrapment occurred on the Hiawatha National Forest in Michigan on the evening of July 1^st, 1988. A Heavy Equipment Boss (HEQB) was leading a team of three tractor plows constructing line along the west flank of the fire. The fire was backing to the west and the tractors were operating 30-50 feet from the fire edge. Conditions suddenly became calm, and the fire started to grow straight up. HEQB was leading the tractors toward a 2-track road when he noticed fire rapidly building. He directed the first two tractors to throttle up move out of the area and then went back to look for the third tractor. HEQB discovered the third tractor operator running and then falling. The HEQB went to the operator and extinguished the fire on his clothing and walked him out of the area. The tractor operator was taken to a burn center with second degree burns over 20% of his body.

What caused the change in fire behavior?

A DC-4 airtanker carrying 2,000 gallons of retardant flew along the right flank of the fire to alert the hand crew working there, circled, came back, and then dropped the retardant. The tanker flew at less than 400 feet above ground level and at approximately 140 miles per hour.

Later analysis by U.S. Forest Service researchers theorized that vortex turbulence developed that triggered extreme fire behavior. A sheet of turbulent air left in the wake of the aircraft rolled up into a strong pair of compact fast-spinning funnels of air. These two counter-rotating vortices likely stayed close together as they descended to ground level, in probably less than a minute, rolling apart as they hit the surface. This invisible sheet of rotating turbulent air left in the aircraft's wake caused the flanking fire to become a high wall of flames.

Discussion Points: Transition from normal to not normal

The report mentions the firefighters were operating how they “normally” would.

• How can we prepare for ‘not normal’ events?
• What are the limitations of basing all actions on current and expected fire behavior.

Resources

• Accident Investigation Report for the Stockyard Fire