This article was first published in Fire Aviation
Yesterday on July 9 a major aircraft and major air carrier came under close call as an obstacle coursed downed a sortie over Washburn Fire in Yosemite National Park.
There was almost no wind over the flames most of the day and the area smoked causing poor visibility which made it impossible for air carriers to fall on the fire. But by 6 p.m., conditions improved and around 6:10 p.m., a pilot aircraft piloting a Tanker 103, MD-87, was over the target when they saw a tree branch falling. above The pilot plane. It fell between the two planes in front of the tanker.
Twitter user Robert, Rob_on_sisukas, captured an audio recording of the radio conversation. We’re not sure who the main plane pilot was talking to, but we’ll call him “dispatcher” for now:
Pilot: Hey, I just want to tell you that a branch went right above us, a very good size, probably 50 feet above us going down and down Penny Tanker 103 and me.
Distributor: All right. trumps. So it’s yesterday’s repeat (unclear)
Pilot: That’s exactly what I do. So if we keep seeing that, we may have to turn it off. I don’t want to take the opportunity to break a window in an airplane or hurt an airplane for this.
Distributor: Absolutely. Keep me updated on this.
#WashburnFire Interesting little chat. He nearly missed you with a tree branch, an air attack, and a 103 tanker. As civilians, we see planes drop payloads. But listen to this dance that goes on behind the scenes of the fire. pic.twitter.com/Dn2CcTZ7qV
– Robert (@Rob_on_sisukas) 10 July 2022
When fires burn intensely in an unstable atmosphere, convection can be triggered in the rising plume of smoke with an enormous amount of energy. As air rushes at ground level to replace the rising column, the developing horizontal winds and fresh oxygen fuel the fire, causing a higher level of intensity. The horizontal and then the vertical movement of air can sometimes move unexpectedly large objects into the sky. Large plumes may rotate as they rise and in extreme cases can actually turn into a fiery tornado. You don’t want to be around when that happens. Fire tornadoes should not be confused with small dust devils or fire swirls.
Surprisingly about yesterday’s incident is that the fires were burning for most of the day, and the tankers couldn’t fly until about 6pm, I looked at the various AlertWildfire cameras a few times and didn’t see any smoke plumes. The cameras I’ve seen may not have been able to see all of the flames, but I remember in the late afternoon the Sierra Fire Watch’s shooting activity increased below, and plumes may have developed.
Damage to firefighting planes from debris flying over a fire is unheard of. This is part of an article I wrote for Wildfire Today in 2018:
During the large vegetation fires in Southern California in 2003, some of the convection plumes were so strong that windshields on six air carriers cracked with pieces of debris that were thrown into the air (Page D-6 of the 2003 California Governor’s Blue Tape Report) ; Huge file 20MB). One pilot saw a plywood sail four by eight at 1,500 feet.
Late this morning, July 10, Washburn Fire burned about 1,800 acres in Yosemite National Park. About 300 acres of these acres are in Mariposa Grove of giant sequoia trees, some of which are 3,000 years old.
Thanks and a tip of the hat out to Kelly.