The fire burned 1,008 acres on the Superior National Forest.
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.
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.
We looked further into what led to the smoky conditions that resulted in numerous vehicle crashes on Interstate 40 west of Flagstaff, Arizona early Wednesday morning, October 19. The smoke on the highway from a prescribed fire was referred to as “pea soup”, and was clearly the cause of some of the accidents, but investigators are not yet ready to say the smoke caused the one fatality when a vehicle was sandwiched between two semi trucks.
During the very early morning hours of Wednesday, October 19, smoke settled into the areas around Interstate 40 between Parks and Williams. An electronic sign warned motorists about smoke, but the severely reduced visibility was not anticipated by the U.S. Forest Service. After the accidents started occurring the Interstate was closed for five hours.
The Kaibab National Forest ignited the Green Base Prescribed Fire on Tuesday, October 18, 2016 immediately north of Interstate 40. The smoke permit issued by the Arizona Department of Environmental Quality anticipated moderate “impacts on sensitive areas”:
Smoke impacts to the following communities of Flagstaff, Parks, Spring Valley, Pittman Valley, Sherwood Forest Estates and some smoke may impact Williams. I-40 may experience moderate smoke impacts in low-lying areas.
The Flagstaff office of the National Weather Service issued a Spot Weather Forecast for the Green Base Prescribed Fire at 5:28 a.m. MST on Tuesday October 18, 2016. It anticipated a “good” maximum ventilation rate for Tuesday, did not specify one for Tuesday night, and for Wednesday it was described as “fair”.
The ventilation rate provides an estimate of how high and how far smoke will disperse. A high ventilation rate suggests that smoke will spread out quickly and through a deep layer of the atmosphere, so that surface concentrations downwind will be lower than they would be with a lower ventilation rate.
The transport winds (from the ground to the mixing height) for Tuesday night were predicted to be “west 5 to 10 knots shifting to the north after midnight, then shifting to the northeast early in the morning.” The wind speed after the shift was not specified. Perhaps this was interpreted by fire managers to mean it would continue at 5 to 10 knots.
The prescribed fire was just north of the east-west Interstate, so a wind out of the northeast would likely push the smoke toward the highway. And if an area is prone to nighttime inversions, visibility can be compromised.
Fox News reported that Cory Mottice, a National Weather Service meteorologist in Flagstaff, said, “[Smoke] always gets trapped after dark,” he said. “It’s just a question of where the wind blows it.”
However that analysis was not described in detail in the spot weather forecast issued by Mr. Mottice’s office. As in many spot weather forecasts, much of the information appears to be generated by a computer, with little interpretation or discussion about how the information will affect the fire. Meteorologists are not expected to be Fire Behavior Analysts, but sometimes a little human-created discussion and interpretation can add value to a computer product.
Below are excerpts from an article at the Arizona Daily Sun:
… A Highway Patrol captain at the scene said smoke in the area reduced visibility down to about 20 feet, Department of Public Safety spokesman Bart Graves said. Sherwood Forest Estates Fire Chief Wayne Marx said even his crews had to stick their heads out the window to watch the yellow stripe on the road as they escorted commuters away from the interstate.
“You couldn’t see past the end of the hood,” Marx said.
One retired meteorologist who lives in the area believes more precautions should have been taken. Parks resident Byron Peterson, who retired from National Weather Service station in Bellemont, said the smoke was already bad on Old Route 66 Tuesday afternoon. Firefighters waved him on, he said, even though there were times when he could not see 10 feet in front of him.
“It was very frightening to say the least,” Peterson said.
He said strong southwest winds coming up over Bill Williams Mountain near Williams formed an eddy of swirling air that then dove down over the prescribed burn, keeping the smoke from dissipating.
“I tried to explain that to people at the Forest Service and it was just like talking to a wall,” he said.
After numerous accidents occurred in thick smoke from a prescribed fire, authorities closed Interstate 40 west of Flagstaff, Arizona on Wednesday. The Kaibab National Forest conducted the burn Tuesday and knew that a wind shift would push the smoke toward the interstate, but they were surprised that the smoke settled near the ground early Wednesday morning rather than being moved out of the area. Electronic signs warned drivers about the potential hazard.
Below is an excerpt from Fox News:
Multiple collisions with minor injuries to motorists and passengers were blamed on smoky haze that settled over the highway for about five hours. Authorities closed I-40 for hours to prevent more accidents.
Police had not immediately determined whether the poor visibility was the cause of a fatal accident after a vehicle was sandwiched between two tractor-trailers before dawn, said Arizona Department of Public safety spokesman Bart Graves.
But the area at this time of year experiences temperature inversions allowing smoke to be trapped close to the ground and hover over the highway, said Cory Mottice, a National Weather Service meteorologist in Flagstaff.
“It almost always gets trapped after dark,” he said. “It’s just a question of where the wind blows it.”
Forest officials thought weather conditions would vent smoke near the freeway more than it did in low-lying areas, Smith said.
“I believed they used good judgment based on the conditions and the information that they had,” said Brady Smith, a U.S. Forest Service spokesperson.
This week the National Park Service reintroduced fire to an area in Sequoia National Park where it had been unnaturally excluded for decades. The 187-acre Dorst prescribed fire near Dorst Campground is expected to help restore a more natural density of fuels and vegetation.
Over the last week Derek Wittenberg has been working with his colleagues on the Beaverhead-Deerlodge National Forest in western Montana (map) burning piles that were created while building a fuel break on the Pole Fire. Other piles were part of a project to promote a Whitebark Pine stand that is resistant to Blister Rust.
Piles like these are often burned while there is snow on the ground in order to minimize the chance of the fires spreading out of control. Some of the keys to success are constructing the piles so that some material remains relatively dry even after rain or snow, and using firefighters that are skilled with a drip torch.
The crew took advantage of the opportunity to conduct training with a Very Pistol.