September 19, 2020 | 4:24 p.m. PDT
Approximately 300 firefighters from Canada are in Washington and Oregon assisting with the Siege of ’20.
September 19, 2020 | 4:42 p.m. MDT
The text in the Tweet below is about Utah, but the map shows the smoke forecast for the Western U.S. through Monday morning. After you click to begin the animation, you can click again to stop and start it.
Wildfire Smoke Update
Areas of haze from wildfire smoke to our west will increase a bit tomorrow, especially later in the day. Note, this will be less dense than the smoke we saw this morning. Periods of haze will remain possible into the upcoming week. #utwx pic.twitter.com/TMLroL297p
— NWS Salt Lake City (@NWSSaltLakeCity) September 20, 2020
The air quality in the western states has improved over the levels seen several days ago.
Bookmark https://wildfiretoday.com/tag/smoke/ so you can easily find articles on Wildfire Today about wildfire smoke.
When crews of wildland firefighters in a remote area have to quickly move to a safer location due to an approaching flaming front, they hike on what they call an escape route to get to a safety zone where they can be out of danger without having to deploy their fire shelters. An average of 11 firefighters die each year while fighting fire. Of these deaths, about 44 percent are caused by entrapment or burnover events.
A key to moving to a safety zone is the travel time. Underestimating the required time can be fatal, in the worst of circumstances. That may or may not have been one of the many factors involved in the deaths of 19 firefighters on the 2013 Yarnell Hill Fire in Arizona.
Firefighters know how long it takes them to hike the three miles within less than 45 minutes while carrying 45 pounds as required by the Pack Test, or Work Capacity Test. From that it’s pretty easy to calculate their miles per hour. But that is on flat ground, a situation that is not always the case when escaping from a wildfire. Throw in steep uphill or downhill slopes, and the times will increase.
Previous research on the subject includes:
A new study uses a different database for the speed at which fire crews can hike. It is titled, “Modeling Wildland Firefighter Travel Rates by Terrain Slope: Results from GPS-Tracking of Type 1 Crew Movement.” (download, 2.3 Mb)
As the name implies, instead of using public crowd-sourced hiking speed data, the researchers issued GPS units to nine Type 1 Interagency Hotshot Crews in the Spring of 2019. Nine of the 11 participating IHCs received seven GPS units each, and the other two received 20 GPS units each. In addition to the GPS units, crews were provided with data collection sheets and armbands to carry the GPS units.
Using data collected by firefighters — a uniquely physically fit population that usually carries heavy loads while moving — provides a set of robust, adjustable travel rate models built from instantaneous travel rate data that can be applied in a variety of contexts.
The data was collected while on training hikes. Rather than rely on GPS for elevation, which is not always accurate, only locations having the more accurate lidar data were used.
The tables below are from the research paper.
Here is an excerpt from the paper:
“The effects of the slope on the instantaneous travel rate were assessed by three models generated using non-linear quantile regression, representing low (bottom third), moderate (middle third), and high (upper third) rates of travel, which were validated using k-fold cross-validation. The models peak at about -3o (downhill) slope, similar to previous slope-dependent travel rate functions. The moderate firefighter travel rate model mostly predicts faster movement than previous slope-dependent travel rate functions, suggesting that firefighters generally move faster than non-firefighting personnel while hiking. Steepness was also found to have a smaller effect on firefighter travel rates than previously predicted. The travel rate functions produced by this study provide guidelines for firefighter escape route travel rates and allow for more accurate and flexible wildland firefighting safety planning.”
The authors of the paper are, Patrick R. Sullivan, Michael J. Campbell, Philip E. Dennison, Simon C. Brewer, and Bret W. Butler.
Updated September 19 | 9:00 a.m. PDT
Friday afternoon strong winds gusting up to 35 mph pushed the Bobcat Fire north down-slope out of the Angeles National Forest into the Antelope Valley foothill communities of Juniper Hills and Valyermo. Structures burned, but no details have been released.
The Incident Management Team reports that the perimeter now envelops 91,017 acres.
Updated September 18, 2020 | 7:06 p.m. MDT
The Bobcat Fire is being pushed northeast into the Antelope Valley by strong winds out of the southwest — 10 mph hour gusting to 35 mph, with 90 degree temperatures and 9 percent relative humidity.
The incident management team had constructed contingency control lines with dozers to prevent the fire from getting into the valley, but the strong winds pushed the flames across the lines. An additional 60 fire engines were called in Friday to augment the forces already on scene.
The LA County Sheriff has issued new evacuation orders and/or warnings for the north and east sides of the fire.
Many of the 10 air tankers were reloading with retardant at the San Bernardino Airport, but late in the afternoon the air tanker base there was running very low on retardant, and directed that the tankers go to alternative bases for their next load. They were expecting that by the time the load after that was needed, the temporary shortage would be mitigated.
Updated September 18, 2020 | 4:45 p.m. PDT
Friday afternoon the northern end of the Bobcat Fire pushed down into the foothills at Juniper Hill and Valyermo. Some structures in the area were destroyed and more evacuation orders were issued. The LA County Sheriff has the latest evacuation information.
Firefighters had to briefly shelter in Fire Station 79 on Valyermo Road as the fire moved through the area. There was a report that a pumphouse at the station burned when the fire spread across the road.
While the fire burns into the desert floor, it is also pushing west, again threatening Mt. Wilson Observatory where approximately six large air tankers are working to slow the spread.
A helicopter is igniting a burning operation, or “strategic aerial firing”, on the eastern perimeter to strengthen containment lines and slow the spread to the east.
There are reports that the community of Big Pines at the intersection of Big Pines Highway and Angeles Crest Highway/2 is threatened.
September 18, 2020 | 8:33 a.m. PDT
The Bobcat Fire in the Angeles National Forest north of Arcadia continued its spread north on Thursday, advancing north of Highway 2.
From the Incident Management Team:
“The Bobcat Fire had very active fire growth in the north end of the perimeter where it reached Juniper Hills and the communities around it, additional aviation assets were requested. Due to the increased fire activity and spread, evacuation orders were expanded to include the northern foothill communities. As the top end of the fire heads northwest and northeast, crews and aviation assets continued to work to keep the fire south of Pearblossom.
“On the west end of the fire, firefighters will be scouting for additional opportunities to build both indirect and direct fire lines to protect the area around Chilao. Fire activity remained active around Mt. Wilson with crews and equipment working very hard to protect infrastructure. To the east, downslope winds activated eastward fire movement near the San Gabriel Reservoir.”
An evacuation warning was issued Thursday night for residents in the unincorporated community of Wrightwood approximately 10 miles east of the fire.
The blaze was mapped overnight at 60,557 acres.
The U.S. Forest Service announced in a news release this morning that a firefighter was killed while working on the El Dorado Fire in Southern California Thursday, September 17, 2020. Neither the name nor the circumstances were released.
CBS News reported that the firefighter had been missing.
Crews had been trying to locate the firefighter, who went missing in the San Bernardino National Forest while fighting the El Dorado Fire, officials said Thursday night, CBS Los Angeles reported. The firefighter was found dead, according to San Bernardino National Forest Public Information Officer Kate Kramer.
This blaze which has burned about 19,000 acres and destroyed 4 homes was started by a smoke-generating pyrotechnic device used at a gender reveal party September 5, 2020.
The fire is northeast of Yucaipa just west of the Apple Fire that burned 33,000 acres 5 weeks ago.
Our sincere condolences go out to the firefighter’s family, friends, and co-workers.
Thanks and a tip of the hat go out to Tom.
The Northwest California/Southwest Oregon area has kept firefighters very busy at times during the last 20 years, as you can see on the map above.
A new fire is rapidly putting itself into that history. The Slater Fire reported September 8 grew to 89,000 acres by September 9 and has now spread to 150,000 acres. That growth, however, has slowed in the last several days.
It started northeast of Happy Camp, California and ran north into Oregon then took a left and crossed Highway 199. It has come to within about four miles of the 2002 Biscuit Fire.
If recent fire history is any indication, the Slater Fire may not even slow down when and if it reaches the Biscuit burn, and of course it depends on the weather, which has moderated this week. The 2017 Chetco Bar Fire and the 2018 Klondike Fire burned for miles into the then 17 or 18-year old fire scar. The entire eastern two-thirds of the Chetco Bar Fire was in the footprint.
Strong winds that drove the dozens of fires September 8 in Oregon are not super rare. The Klondike Fire west of Grants Pass started July 15, 2018. In early October it had become virtually dormant, but a few hot spots were revitalized by an east wind event on the 14th. According to an article in the Mail Tribune the suddenly vigorous fire was transporting burning embers that started spot fires six miles out ahead of the flaming front:
“Extreme spotting” propelled fine embers up to six miles ahead of the main fire, dropping the live ash right between firefighters’ tents and close to people’s homes.
“We even had to move our own fire camp,” [information officer Kale] Casey said.
So if the weather this year is anything like it was two years ago, firefighters could be busy in the area for at least another month.