Weather, human error blamed for fire

By Steve Estes

An interagency review committee found that both environmental and human conditions were partly to blame for the prescribed burn that flamed out of control Sept. 15 and charred 100 acres of the National Key Deer Refuge on Big Pine Key.

The fire also forced the evacuation of 42 homes in the Pine Heights subdivision, located south of the planned burn area and about midway between Eden Pines and Port Pine Heights down Key Deer Blvd.

In the committee’s executive summary of the report released late last month, the after-burn review was “conducted to examine the causal factors of the escape and identify recommendations to improve future prescribed fire planning and implementation.”

According to the official time line, the fire was ignited at 10:25 a.m. Sept. 15, nearly 90 minutes after originally planned due to wind conditions.

Just 90 minutes after that, officials report that the fire’s behavior changed along with the weather, and embers jumped as much as 100 feet over the planned end of the burn area.

Firefighters on scene cut fire breaks to promote a controlled back burn on the primary fire and at 4 p.m. evacuation of Pine Heights was ordered.

The report claims the wildfire was contained at 100 acres by 8 p.m. that evening.

After a Sept. 18 meeting of involved personnel, the report states that “Human and environmental factors were both considered to play a role in the incident. Material factors were considered but were not found to contribute.”

Local residents with experience in prescribed burning said that the fuel load on the ground may have played a part in the intensity of the fire as what started as low-burning, slow-moving flames accelerated and eventually reached into the tops of the pine trees located in the burn area.

According to the report, the fire burned hotter than anticipated, with fuel loads drier than the 10-year average for both the 1,000-hour pre-burn index and the 100-hour pre-burn index.

The report states, “The relative humidity dropped below forecasted levels, however, this was only part of the environmental conditions contributing to the escape. The review team considers the overall dry conditions as a contributing factor to the escape.”

In past burns, ignition was called off unless more than half-an-inch of rain had fallen on the area in the past 24 hours. September was one of the driest months in recent memory with just over one inch of rainfall in the 30 days preceding the burn.

The report states that weather data form the National Key Deer refuge weather station reported the relative humidity at 43 percent, though measurements on scene recorded 61 percent.

Those familiar with past successful burns report that ignition would be called off unless the relative humidity was around 75 percent.

During the fire, the lowest relative humidity recorded was 36 percent.

Though material wasn’t cited as a contributing factor, the report states that a “significant amount of substrate was exposed due to effective consumption of surface fuels.”

The report recommends changes to both the decision-making process and the environmental parameters.

According to Dana Cohen, refuge fire specialist, the minimum requirement for a prescribed burn is 50 percent relative humidity. The report, however, says that when burning in the wooded/urban interface that is Big Pine Key, the humidity factor should be increased to greater than 50 percent.

The report also suggests that the burn be conducted within 24 hours of a minimum rainfall of one-half inch.

Cohen also said that the wind speeds, which began in low single digits, increased during the course of the fire to 12 miles per hour, contributing to the fire’s escape from containment. The report suggests that fire not be ignited unless wind speeds are greater than zero to six miles per hour and pushing in a direction that keeps smoke, and potential wildfire, away from the nearest residential units.

The report also suggests that the inexperience of personnel on the ground contributed to the fire escaping containment.

“The majority of this 22-person burn crew had limited experience burning together in pine rockland fuels. While more than one-third of the personnel (carried the requisite qualifications) few work together operationally on a regular basis,” states the report. “Two of the crewmembers had no previous burn experience.”

The report also suggests that the use of a burn boss trainee as the second-in-command on the burn boss’ first burn after qualifying as such exacerbated the inexperience issue.

“The review team considers the limited experience of key personnel in these fuel types was a contributor to the escape,” states the report.

The report recommends that in the future, more experienced personnel be placed in positions of control, and only experienced wildfire crewmen be placed in operational positions.

Most local residents were upset with the refuge after the burn, mostly for what they called a lack of notification that the burn would proceed. The report addressed that as well.

“While the refuge’s pre-burn public notification was far more than the average prescribed burn in the region, the sensitivity of burning on the (refuge) dictates that additional methods should be considered,” states the report.

In past burns, refuge personnel placed large signs at the intersection of Key Deer Blvd. and Watson for any burns north of that intersection. Those signs were missing this time. In past burns, refuge personnel have also delivered notices door-to-door in potentially affected neighborhoods. Believing that Port Pine Heights, north of the burn area, would be most profoundly affected by potential smoke, no individual notices were given to Pine Heights residents, though they turned out to be downwind of the burn zone.

The report also suggests that prescribed burning will continue on refuge lands.

“The team believes that the recommendations above, as well as continuing fuels treatments and outreach efforts will ensure continued success of the fire management program.”