Retreat and defeat in the boreal forest
An attempt to slow the growing wildfire with a controlled burn called for preparations to avoid letting the man-made flames reach the city. Crews worked hard, and on May 2 the mood was cautiously optimistic.
FORT MCMURRAY Smoke blanketed the scorched boreal forest on Monday morning, May 2, 2016. Under its cover slept Fire 9.
Through the previous evening, the wildfire had made its first push toward this northern city. The wet and cold of the night had at last halted the march of flames. In the respite, Fort McMurray fire bosses took to helicopters to try to get a sense of their adversary.
The veil of smoke stretched for hundreds of hectares west of the city. It confounded any precise measurement. Fort McMurray forest area manager Bernie Schmitte and his team estimated that the fire, blown by swift west winds, had on May 1 burned through 500 to 750 hectares of forest, taking on a cigar shape and aimed right at Gregoire, a suburb of more than 1,500 homes in south Fort McMurray.
That afternoon of May 2, the sun cooked the already parched boreal forest to 27 C, but good news came when the wind picked up. It reversed direction, blowing east-towest, taking the fire away from the city. Schmitte and his team of 20 firefighters and eight operators on two bulldozer crews had a window to try to contain Fire 9’s threatening finger pointing at the city.
When a wildfire burns hot and fast, no amount of retardant or water from air tankers will stop its progress.
The best bet against such a blaze is what wildfire experts refer to as burnout and backfire. Heli-torch specialists in helicopters rigged with torches spray flaming gasoline gel on a line of trees below to ignite a burnout. They attempt to torch a thin strip of the forest between the main body of the wildfire and a man-made or natural control line, such as a road or a river.
The controlled burn is to move toward the main inferno, either blown there by the day’s winds or by the great sucking in of oxygen by the primary fire itself. If the strip burns out thoroughly, it takes away the fuel that would otherwise keep the wildfire charging ahead. The hope is to slow the wildfire so the air tankers and ground crews can be more effective.
But Schmitte realized a backfire cannot be ignited on the edge of a city of 88,000 people. If the wind picked up and changed direction, the controlled burn could itself turn and threaten Fort McMurray. Schmitte needed protection, a line of defence through the forest that could stop a controlled burn if it moved in the wrong direction.
His heavy machinery crews went to work on a dozer guard, the idea being that bulldozers would take out a six-metre-wide swath and enclose the hot tip of Fire 9. Only then could they attempt a backfire.
The dozer crews had a tough test. Two small rivers, the Horse and the Hangingstone, wind their way through the forest west of Fort McMurray, creating deep valleys and twisting slopes.
No road or cutline existed to reach where the dozer guard was needed. Buried pipelines crossed the area. A shallow pipe might rupture under a bulldozer’s weight. The buried pipes had to be located, marked and covered over with swamp mats for safe crossing. And, of course, evacuation plans to ensure the safety of the men and machinery were a necessity.
For all that, by late afternoon the fire crews made progress. A few kilometres of dozer guard hugged the tip of Fire 9.
Twenty-eight firefighters, seven helicopters and two planes worked the northwest edge of the fire on May 2. Of the latter, one was a Convair 580 air tanker and one an Electra water bomber, with Ken Buchanan the pilot. In the city, some looked at the huge smoke column above the fire and worried, but it seemed to Buchanan, a 30-year veteran fighting wildfire, that things were going well. The fire was coming under control on its edge closest to the city.
At a late afternoon news conference that day, Schmitte was guarded but optimistic. The fire had doubled in size but was most active in its southwest corner, away from the city.
“We have some good news here,” he told reporters. “Our guys are feeling pretty good after today.”
To lead the firefight, Schmitte called in incident commander Doug Smith and the Provincial Type 1 team — Alberta’s best, most experienced specialists in fighting wildfire.
At its 5 p.m. meeting that same day in Fort McMurray, fire behaviour specialist Dave Schroeder gave the Type 1 team some troubling news.
The forecast for the coming day, Tuesday, May 3, wasn’t so bad: a hot day but with only light winds.
On Wednesday, May 4, or early on Thursday, May 5, however, Schroeder said a high pressure cold front was expected to blow in dry and gusty, with winds coming first from the southwest, then shifting to blow in hard and long from the northwest.