Millions of raisin-size firebrands drove Fort Mac fire: New
Sunday, May 14, 2017, 8:52 PM - A little more than a year after the first flames sparked, people are looking back on the devastating Fort McMurray fire, and the lessons learned in its wake.
The fire grew rapidly and forced a historic evacuation of the Albertan city, with more than 80,000 people fleeing in a mass exodus.
In the city they left behind, more than 2,400 structures burned before the flames were beaten back, and the disaster was one of Canada's most costly, with some $4 billion in insurable losses.
Now, a new report from the Institute for Catastrophic Loss Reduction has new insight on why some homes burned, and why others survived.
The report's author, Alan Westhaver, a 27-year veteran of Canada's national park system who now owns an environmental consulting firm, says many of the homes that burned were those that were showered with embers from the fire, which ignited shrubs, decks and other sources of fuel that were near the homes.
"Based on sites visited, no instances were observed where home ignition could confidently be attributed to direct contact by flames of the burning forest, and there were very few observations where home ignition was likely due only to radiant heat from the forest," Westhaver writes.
Westhaver says the flames that resulted would have spread, worsening the situation and making the conflagration more widespread.
"This progression can only be broken, and disaster avoided, by substantially increasing the proportion of homes that are resistant to ignition – especially by embers," Westhaver says. "Primarily, it was millions of raisin-sized firebrands searching for places to carry on with combustion, and succeeding all too often."
The report includes a number of recommendations, including better planning, and changes in landscaping to minimize the proximity plants to homes that might be ignited in future fires. A link to the full report is below.