Report released on escaped prescribed fire in northern Minnesota

The fire burned 1,008 acres on the Superior National Forest.

Foss Lake Fire

Above: Photo of the Foss Lake Fire, from the report.

A report has been released for a prescribed fire that escaped on May 19, 2016 and burned an unexpected 1,008 acres 10 miles west of Ely, Minnesota. The U.S. Forest Service had intended to burn 78 acres, but extremely dry conditions and winds pushed a spot fire beyond the capabilities of the Hotshot crew and the engine initially assigned to the project. The fire danger index for the Energy Release Component at the time was setting 20-year maximums.

Foss Lake Fire map
The perimeter of the planned prescribed fire is outlined in black, in the gray shaded area. The escaped area is in red.

You can read the entire report here, but below are highlights:

  • Some of the firefighting resources listed as contingency forces in the burn plan were national resources not committed to the prescribed fire and were assigned to other fires when needed on the escape.
  • According to a spot weather forecast the conditions that morning were at the hot end of the prescription and in the afternoon may go out of prescription. There was a discussion about possibly having to pause ignition for a period of time in the afternoon.
  • The test fire began at 11:40 a.m. Soon thereafter the primary ignition began.
  • Within 40 minutes of starting the test fire spot fires began to occur near the fireline, but they were suppressed. At 12:50 p.m. a larger spot fire, 1/4 to 1/2 acre, was discovered 100 yards north of the main burn by firefighters patrolling in a canoe. The firing boss ordered the igniters to slow down.
  • When the larger spot fire occurred, firefighters installed a hose lay from a river to the site but were not able to start a pump to supply the water. A replacement pump that had been working in another area that day was brought in but it also refused to run.
  • At 12:53 p.m. a water-scooping Beaver air tanker that could carry up to 130 gallons of water was requested by the Zone Fire Management Officer (ZFMO) who was at the site, and 11 minutes later he asked for a Type 3 helicopter.
  • At 1:41 p.m. personnel on the fire declined offers or suggestions for “heavy aircraft” and also a Type 1 helicopter that had become available.
  • Between 1:59 p.m. and 2:26 p.m. personnel on the fire requested the Type 1 helicopter, air attack, two 20-person crews, a CL-415 scooping air tanker, and two large air tankers.
  • At 2:07 p.m. the Burn Boss declared the escaped fire to be a wildfire and began shutting down the original prescribed fire.
  • At approximately 1700 a Type 2 Incident Management Team was ordered for the escaped wildfire, which was then several hundred acres in size.
  • At 10:09 p.m. all personnel on the prescribed and escaped fires were released and returned to Ely.

Our original report on the escaped prescribed fire last May.

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Author: Bill Gabbert

After working full time in wildland fire for 33 years, he continues to learn, and strives to be a Student of Fire.

One thought on “Report released on escaped prescribed fire in northern Minnesota”

  1. Another interesting read in Wildfire Today.

    As a Monday morning quarterback it is easy to see where things could have been done differently on this PB. One item from the report that raised a flag was the use of the Canadian Fire Weather Index (FWI). The fuel types found in northern Minnesota are the same as those in the Thunder Bay / Fort Frances Districts in Ontario. Therefore, the Canadian Fire Danger Indices should aid fire behaviour situational awareness for any fire in the BWCAW or Superior National Forest. According to the report, the fine fuel moisture code (FFMC) on ignition day was 93. That number would raise the level of concern for Canadian firefighters based on our familiarity with the FWI system.

    For the readers not familiar with the FWI and it’s FFMC, here is a brief overview of the FFMC values from Natural Resources Canada. The FFMC indicates the relative ease of ignition of fine fuels with the code running from 0 to 101. At values under 74, there is little chance of ignitions, and 80 is where there is continuous surface fire spread. When the FFMC is above 89 there is a high probability of spot fires; fire danger ratings would be High to Extreme. A quick rule of thumb is 101 minus the FFMC equates to the approximate fine fuel moisture content.

    During my fire career in northwestern Ontario, I had the opportunity to learn from, and work for a gentleman by the name of Jim Moorley. Many of us remember some of his “old school” sayings that related to situational awareness. He liked to remind us that when the FFMC is above 91, we should expect problems, and have a tanker in your pocket. We also knew how fires burning at these FFMC levels would respond instantly to small-scale increases in wind speed. Based on the indices for the Foss Lake Prescribed Fire, which were at the high end of the prescription, it would have been nice to have a pair of CL-415’s sitting in Ely.

    From the report:
    Element 7 Prescription: Many times the Environmental Prescription is developed through
    experience and knowledge of the area’s weather. There is a need to include the wind conversion factor in the Burn Plan. The Canadian Indices are a good reference, but for only those that are familiar with them. Burn personnel need to be very careful and identify which indices you are using and ensure they correlate with each other.

    In my opinion, better knowledge of the FWI, FFMC, and the Initial Spread Index (ISI) may have influenced the decision to “drop the match” on this prescribed burn.


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