Going to a Fire in Alaska?
Check out these lessons from two tree strike incidents that occurred in the Fairbanks area.
August 8, 2010. Bucking and swamping was in progress when a gust of wind blew over a black spruce a couple tree lengths away, which then struck a second tree while on the way down, which struck a third tree causing it also to fall. Tree #3 which was approximately 8” dbh, struck the firefighter with its top section. The sawyer was bucking with the saw and the swampers busy moving fuel to the bone-pile, so the falling domino trees were seen only by the CRWB(t) observing the operation some distance away.
- Key Factor: Trees in permafrost conditions develop shallow root systems. Fires burning deeply into the organic layer containing those root systems frequently result in consumed roots and unstable trees.
- Mitigation: Hazard trees need to be evaluated and felled prior to mop-up activities. Mop-up crews cannot assume that prior snagging operations mitigated all hazard trees. Increasing winds in burned-over timber, as well as recently observed wind-throw, should act as watchout triggers to have one eye looking up, or designating a snag look-out for each working group. Good spacing between swampers or other crewmembers involved in mop-up is also key. The working area of this allotment was snagged again after this incident.
At approximately 1820 hours (ADST) on June 16, 2011 while conducting mop-up
operations on the Hastings Fire, near Fairbanks, Alaska, a member of the ZigZag
IHC was struck by a tree. A medium helicopter already working the fire was
quickly staffed with medical personnel and used to extract the injured crew
member from a rapidly improved sling spot near the injury location. The injured
crew member was then flown directly to Fairbanks Memorial Hospital.
- This tree strike occurred in a mixed timber stand comprised of 8-10 inch aspen and 12-24 inch white spruce.
- A predominate shallow duff layer allowed the fire to penetrate down to mineral soil.
- The tree that impacted the IHC member had a very shallow root system that had not been impacted by any other activities other than the fire.