Recently, I read a report, titled “Why some homes survived: Learning from the Fort McMurray wildland-urban interface fire disaster” as written by Alan Westhaver M.Sc. for the Institute for Catastrophic Loss Reduction. At 70 pages, this is a detailed study of how FireSmart principles affected the outcome of Fort McMurray home survivability during the worst urban-interface fire event in Canadian history. There is no way for me to summarize all the details but there were a few nuggets of information.
There are thousands of wildland fires in Canada every year and this number is increasing. Wildland fires that impact urban communities are also increasing in frequency and structural loss magnitude, most notable being Kelowna (2003) - $200 Million, Slave Lake (2011) - $750Million and of course Fort McMurray (2016) - $4Billion. These are the worst of the worst but the numbers are definitely on the rise. As stated by the Canadian Council of Forest Ministries (2016) “there has been a serious and sustained increase in extreme wildland fire behaviour and wildland-urban interface events”. The wildfire problem is dynamic due to population growth/redistribution and encroaching recreational and industrial development. Definitely two factors prevalent here on Quadra. The most sophisticated models suggest a Canada wide increase of 2 to 4 times in annual area burned, greater fire intensity, lengthening of the fire season and higher rates of spread. These are unavoidable facts. We all live in a fire zone and we need to learn how to deal with it.
In Fort McMurray, 90,000 people were evacuated. Over 2400 homes and major structures were directly affected or destroyed. Many of the neighbourhood communities were well planned based on FireSmart principals. In addition, there were natural features such as the Athabasca River that were thought to provide adequate wildfire firebreaks. Unfortunately, no one was truly prepared for the intensity and speed of the blaze. Fort McMurray was simply overwhelmed in every measure.
There were homes that survived even inside neighbourhoods where destruction was complete. There were also homes completely destroyed inside neighbourhoods that suffered minimal fire damage. How does this happen?
The investigation pitted FireSmart evaluation principals against direct evidence of outcome. What was more than evident was:
- Firebrands (burning airborne embers) from the approaching blaze were a key contributor to spot fires well in advance of the fire front. These spot fires were distributed throughout Fort McMurray and took many homeowners by surprise as the fire front itself may still have been a great distance away. The firebrands accumulated like glowing snow in corners and under combustible materials.
- Vegetation within the 10-meter zone of a home either benefitted its survivability or was a key contributor to destruction. This correlated directly to plants being either coniferous or deciduous and to their placement in relation to fire exposure. This was often the home Achilles heal with ornamentals such as Mugo Pine, Juniper and Cedars within 1 to 3 meters of an eave or window. Conversely, well-watered deciduous landscaping elements actually provided some level of fire protection.
- Fire pathways via structures (fences or sheds) directly adjacent the home contributed greatly. Contents such as stored building materials, firewood, ATV’s, motorcycles, boats, and lawn mowers when combined with volatile fuel sources from onboard fuel tanks, gas cans and propane tanks produced high intensity long duration ignitions.
- An estimated 70% of the homes had vinyl siding and surprisingly, many of those homes survived. Vinyl siding would melt off from radiated heat but not necessarily ignite. Depending what building material was underneath, the home either survived or ignited. As well, double pane vinyl clad windows and doors often survived and maintained structural integrity.
- Fine surface fuel accumulations as well as wood chip landscape mulch directly beside the home contributed greatly to rapid fire spread.
- Untreated vegetation in priority zone 3 (30 plus meters away) did not seem to provide any correlation as to which home survived and those that were destroyed. However homes with FireSmart treatments inside of Priority Zone 1 (up to 10 meters surrounding the home) and Priority Zone 2 (up to 30 meters surrounding the home) improved odds by as much as 80%.
- Wooden decks with combustible contents above and below had a huge impact. Even the decks age and maintained condition were contributing factors. Older decks often had accumulations of fine debris in the deck cladding gaps. Areas directly below the deck were often tinder dry with many combustible items in storage. Planters as well as deck furniture became fuel from whirling firebrands collected on surfaces.
- Condition of the surrounding landscape was a major issue. Short cut and irrigated lawn surrounding the home proved to be a significant barrier. Long dry grasses simply spread the fire path directly to the home.
- Roofing materials such as asphalt shake and metal proved their worth as significant barriers to fire ignition. However, if the roof and gutter system were debris filled, the risk of ignition dramatically increased. Older asphalt shake roofs with curled edges also proved to be significant hazards, again, collecting points for firebrands.
- The homes of Fort McMurray proved to be as much a source of fuel for fire as did the surrounding forest. One home ignition often led to another. If the majority of homeowners within a neighbourhood were generally practicing FireSmart principals but certain individuals chose not to participate, then the entire neighbourhood became endangered. The FireSmart process must be a complete community-based effort.
The findings described above are far from comprehensive and clearly do not do justice to the report in its entirety. What it does do is reinforce fundamental FireSmart principals.
- Have an evacuation plan with the steps every member of the household must take. You may only have minutes and most likely you will not be calm and rational.
- Add to your FireSmart protective arsenal with a Sprinkler Protection System. It can create a high humidity zone around your home. This can include rooftop and deck surfaces. Even running them for an hour before an event will significantly increase the odds of survivability.
- Make sure everyone knows how to hook up and run the SPS set up. This needs to be routinely practiced.
- Remove and transplant coniferous landscape elements that are placed too close to the home.
- Clear your gutters and rooftops of debris.
- Use a leaf blower and rake to remove fine fuels from the immediate vicinity of your home.
- If a fire emergency has been declared and if you have time, move garden furniture and combustibles at least 10 meters away from the home.
- Consider limbing trees and clearing brush debris for as much as 30 meters surrounding your home. It can be done in stages.
For information on the FireSmart evaluation process as well as additional mitigation suggestions, please visit -www.regionaldistrict.com/media/199511/Firesmart_Homeowners_Manual.pdf
We live in a natural rural environment where we must learn to coexist with fire. Take precautionary measures now well in advance of a potential fire event.
Mike Gall – LFR
Quadra Island Fire Department