The challenge remaining on the 4,759-acre Washburn Fire in Yosemite National Park is to corral the east side where it has spread into the Sierra National Forest, a very steep area with large rock outcroppings.
They have established three helispots on the north side of the South Fork of the Merced River and one on the south side that could be used for inserting firefighters. Their plan is to insert a small group of hotshots on the east side of the fire south of the river at Helispot 5 on the map below, being pointed to by Planning Operations Section Chief Matt Ahern. Their task will be to construct fire line on that corner, west of Iron Creek, working downhill and uphill to anchor and stabilize the fire at that point. This would then enable hotshot crews to “come off the top”, said Mr. Ahern.
Contingency fire lines are being constructed some distance from the fire on the south and east sides in case extreme weather drives the fire in those directions.
The Buck Cabin east of the fire built in 1931, was recently rehabilitated at great expense. The wood shake shingle roof was replaced with — another wood shake shingle roof. Since it is very, very vulnerable to fire, and in a roadless area, firefighters will be flown by helicopter to the area, rappel to the ground, and wrap it in foil-based structure wrap.
Most of the fire edge near the Mariposa Grove of giant sequoias has been secured with fire line, Mr. Ahern said.
“Overall the incident is in a very good place,” said Mr. Ahern. “We still have a tremendous amount of work and a heavy commitment of hotshot crews and aerial resources to pinch off Iron Creek.”
The infrared video below shot at 10:39 p.m. July 14 shows the east side of the fire.
Threatens 3,000-year-old giant sequoia trees in Yosemite National Park
Updated 5:00 p.m. PDT July 13, 2022
The Washburn fire in Yosemite National Park has kicked up Wednesday afternoon like it has every afternoon since it started July 7.
Helicopters have been assisting ground-based firefighters on the east side of the fire today, but due to spot fires and increased fire activity in the afternoon they called in two large and one very large air tanker to slow the spread.
A community meeting about the fire will be streamed live on Facebook at 7 p.m PDT on July 14.
The FIRIS aircraft shot video of the fire earlier today:
Most of the fire activity on the Washburn Fire over the last 24 hours has been on the east side where it has burned out of Yosemite National Park and into the Sierra National Forest. So far crews have been able to suppress all of the spot fires on the north side that crossed the South Fork of the Merced River and ignited the five-year-old vegetation in the footprint of the 2017 South Fork Fire.
The incident management team is evaluating the feasibility of building a fireline on the east side between Raymond Mountain and the river in order to stop the movement beyond that point.
On a flight at 10:45 p.m. an infrared line-scanning aircraft mapped the fire. An infrared analyst interpreted the data and found that it had burned 3,772 acres.
Below, another aircraft using a different system, FIRIS, reported it was 3,843 acres at 10:06 p.m. July 12. Their infrared video, looking east, is below.
Fire crews are making progress on the Washburn Fire in Yosemite National Park — the south and west sides are starting to look more secure. At 12:53 p.m. Tuesday it was mapped at 3,516 acres.
Approximately 340 acres of the blaze is within the Mariposa grove of giant sequoias, some of which are close to 3,000 years old. The more than 500 mature giant sequoias are adjacent to heavy fuels and have so far avoided serious damage from the fire, the National Park Service reported Tuesday.
On Monday, firefighters suppressed about 15 spot fires on the west side of the fire that were across Highway 41. They now have a fire line around the Wawona community and have structure defense equipment in place.
On the northeast side the line is complete from the highway down to the South Fork of the Merced River and around the community. On the north side the fire has reached the river in most places and crews are putting out spot fires as they occur across the river in the fire scar from the 2017 South Fork Fire.
The east side continues to spread. Firefighters assisted by air tankers have constructed fire line along the ridge east of Wawona Point and so far that is holding. About a mile to the east hotshot crews are evaluating the feasibility of building a fireline between Raymond Mountain and the river in order to arrest the movement beyond that point.
Yosemite Superintendent Cicely Muldoon said the fire was caused by humans.
“As you all know there was no lightning on that day so it is a human start,” Muldoon said Monday night. “It’s under investigation. That’s all I can say about that right now. We’re looking at that really hard.”
The weather for this week will continue to be warm and dry due to a strengthening high pressure system. Winds should remain light to moderate and mostly terrain driven. Temperatures will reach the low-90s and relative humidity will be in the 20-30 percent range.
Yesterday July 9 a lead plane and a large air tanker had a close call while on a retardant dropping sortie on the Washburn Fire in Yosemite National Park.
There was virtually no wind over the fire most of the day and the area was smoked in causing very poor visibility making it impossible for air tankers to drop on the fire. But by 6 p.m. conditions had improved and at about 6:10 p.m. a lead plane was leading Tanker 103, an MD-87, over a target when they saw a falling tree branch above the lead plane. It fell between the two aircraft, 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 lead plane pilot was talking to, but we’ll call it “dispatcher” for now:
LEAD PLANE: Hey I just want to let you know that a branch went right over the top of us, pretty good size, probably 50 feet above us coming down and fell right in between Tanker 103 and myself.
DISPATCHER: OK. Copy. So it’s repeat of yesterday’s (unintelligible)
LEAD PLANE: That’s exactly what I’m getting at. So if we keep seeing that we might have to knock it off. I don’t want to take a chance on busting a window in an airplane or hurting an aircraft for this.
DISPATCHER: Absolutely. Keep me updated on this.
#WashburnFire interesting little chat. Near miss with a tree branch and Air Attack and Tanker 103. As civilians, we just see planes dropping loads. But listen to this choreography that goes on behind the scenes of fire. pic.twitter.com/Dn2CcTZ7qV
When a fire is burning intensely in an unstable atmosphere the convection in the rising smoke column can be powered by a tremendous amount of energy. As air at ground level rushes in to take the place of the rising column, the developing horizontal wind and the fresh oxygen feed the fire, causing an even higher level of intensity. The horizontal and then vertical movement of air can sometimes transport unexpectedly large objects up into the sky. Large columns may rotate as they rise and in extreme cases can actually become a fire tornado. You don’t want to be nearby when that happens. Fire tornados are not to be confused with small dust devils or fire whirls.
What is surprising about the incident yesterday is that the fire was smoked in most of the day, and tankers could not fly until about 6 p.m. I looked at various AlertWildfire cameras a few times and did not see any smoke columns. Maybe the cameras I saw were not able to see all of the fire, but I remember that late in the afternoon fire activity increased at the Sierra Fire Watch camera below, and columns may have developed.
Firefighting aircraft being damaged by debris being lofted into the air over a fire is not unheard of. Here’s 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 columns were so powerful that the windshields on six air tankers were cracked by chunks of debris that were being hurled into the air (page D-6 in 2003 California Governor’s Blue Ribbon Report; huge 20 Mb file). One pilot saw a four by eight sheet of plywood sail past at 1,500 feet.
As of late morning today, July 10, the Washburn Fire has burned about 1,800 acres in Yosemite National Park. About 300 of those acres are in the Mariposa Grove of giant sequoia trees, some of them 3,000 years old.
It has burned into a grove of giant sequoia trees, some of which are 3,000 years old
Updated 5:08 p.m. PDT July 11, 2022
Late Monday afternoon activity on the Washburn Fire increased substantially. There have been reports of at least one spot fire on the north side of the South Fork of the Merced River. There were also reports of spot fires across highway 41 on the west or northwest side of the fire.
Satellite heat detections at 2:36 p.m. Monday showed numerous heat sources east of the earlier perimeter of the fire across the park boundary on the Sierra National Forest, and on the northwest side of the fire between Highway 41 and the river.
In mid-afternoon the FIRIS aircraft mapped the fire at 2,720 acres.
Updated 7:11 a.m. PDT July 11, 2022
The Washburn Fire in Yosemite National Park in California continued to spread west, north, and east on Sunday. On Saturday and Sunday the size increased by 749 acres, bringing the total to 2,340 acres according to a mapping flight Sunday at 10 p.m.
Approximately 340 acres of the fire are within the Mariposa Grove of giant sequoias. While protective foil-based structure wrap is not being used on the sequoias themselves, additional methods are being employed including the removal of fuels around the trees, and ground-based sprinkler systems to increase humidity and fuel moisture near the sequoias. The Mariposa Grove has a long history of prescribed burning and studies have shown that these efforts reduce the impacts of high-severity fire.
Firefighters are constructing direct fireline on the fire edge where possible, but are also using tactical firing to tie it in with barriers, such as Highway 41 on the west side.
Evacuations are in effect in the Wawona area. A map is available showing the locations. The Wawona Road (Highway 41) is closed from the South Entrance to Henness Ridge Road. Yosemite West remains accessible from the northern side of the Wawona road.
The weather forecast for the fire area (6,400 feet above sea level) predicts for Monday and Tuesday 81 degrees, 3 to 8 mph west and southwest winds, relative humidity in the low to mid-20s, partly cloudy skies, and no chance of rain.
Updated 5:34 p.m. PDT July 10, 2022
The Washburn Fire, part of which is burning in a grove of giant sequoias in Yosemite National Park, has grown to 2,045 acres, according to a mapping flight at about 4 p.m. Saturday. Most of the additional acres are on the north and east sides. It spread closer to the South Fork of the Merced River, but at that time had not crossed. The east side has moved across the county line, from Mariposa into Madera county.
Three large air tankers and a very large air tanker dropped retardant along a ridge in mid-afternoon, pretreating it in anticipation that when the fire reaches that location the spread will be slowed or stopped.
Late in the afternoon the fire activity increased substantially, sending up a substantial smoke column which was blown off to the north.
9:11 a.m. PDT July 10, 2022
With very little wind Saturday, the Washburn Fire continued to spread in and adjacent to the Mariposa grove of giant sequoia trees in Yosemite National Park in California. In spite of the relatively mild weather conditions, spot fires are occurring hundreds of feet out in front of the leading edge. The growth into the grove has been limited due to previous prescribed fires that reduced the amount of fuel on the ground, and by the efforts of firefighters. Some of the trees are about 3,000 years old.
While the huge, very old trees are adapted to fire, they are not prepared for human caused climate change and the current “exceptional drought” conditions that have led to low soil and fuel moistures. The monster trees are more vulnerable to the existing weather and fuel conditions. They only grow in about 70 groves located on the western slopes of California’s Sierra Nevada Mountains. They are the largest trees on Earth in terms of volume.
The fire was mapped Friday night at 1,591 acres. Approximately 300 acres are in the Mariposa Grove of giant sequoias, on the west and north sides.
Smoke at times on Saturday degraded visibility to the point where retardant-dropping aircraft were grounded. Most of the movement of the fire was on the north end where it is working its way down-slope to the South Fork of the Merced River, which is also the southern edge of the South Fork Fire that burned 7,563 acres in 2017. The footprint of that 5-year-old fire scar will not stop the fire by itself, but there will be less resistance to control as it spreads through the lighter fuels.
The Washburn Fire is burning in mostly high load conifer litter with a heavy dead and down component as well as numerous standing dead trees.
There was very little wind on the fire Saturday and none overnight at Fish Camp, south of the fire and 1,000 feet lower where the minimum humidity Saturday was 31 percent but rose to 83 percent by 7:31 a.m. Sunday. Warmer and drier weather is predicted for the next few days.
The weather forecast for the fire area on Sunday calls for temperature around 80, relative humidity 26 percent, and ridgetop winds out of the west at 5 mph gusting to 12 mph in the afternoon. For Sunday night, 66 degrees, 33 percent RH, and 5 to 10 mph northwest winds in the evening shifting to east after 9 p.m. Monday should bring 83 degrees, 20 percent RH, and 5 to 10 mph winds out of the southeast shifting to southwest by 11 a.m.
Preparing for fire: The Grizzly Giant is the most renowned giant sequoia in Yosemite National Park. Standing at 209 feet it is the second largest tree in the Yosemite, and one of the most photographed.The Grizzly Giant is in the Mariposa Grove impacted by the Washburn Fire. pic.twitter.com/jnIlm9Gemn
— Yosemite Fire and Aviation Management (@YosemiteFire) July 10, 2022
Washburn Fire has burned hundreds of acres in the Mariposa Giant Sequoia Grove
Updated at 5:26 p.m. PDT July 9, 2022
Smoke over the Washburn Fire is preventing air tankers from dropping retardant.
The FIRIS mapping aircraft reported at about 4 p.m. that the fire had grown to 1,384 acres
Updated 8:03 a.m. PDT July 9, 2022
The Washburn Fire in Yosemite National Park in California was very active throughout Friday night and into Saturday morning. The photo below taken at dawn on Saturday shows a convection column of smoke, something you don’t often see over a wildfire at dawn.
The National Park Service, which often “manages” wildfires in Yosemite rather than aggressively putting them out, said they are fully suppressing this fire. California Interagency Incident Management Team 13 has assumed command, and additional firefighting resources will continue to arrive over the coming days.
A mapping flight at 10 p.m. Friday found that it had grown to 703 acres, a number that has no doubt been exceeded in the subsequent hours.
The overnight weather at the Fish Camp weather station south of the fire 1,000 feet lower in elevation, recorded a maximum relative humidity of 53 percent and light winds out of the west and northwest. The spot weather forecast issued Friday afternoon predicted for Saturday 82 degrees, 27 percent relative humidity, and 6-12 mph afternoon ridgetop winds gusting to 18 mph out of the southwest and west. This should influence the fire to continue spreading to the northeast and east.
Approximately 155 acres of the fire has burned into the west side of the 1,300-acre Mariposa giant sequoia grove. The Park Service has been conducting prescribed fires within the grove for years, including about seven since 1999. This should slow the spread in the grove and reduce the fire intensity compared to other locations that do not have similar recent fire history. It remains to be seen how much sequoia mortality will occur under the present low fuel moistures and “exceptional drought” conditions.
It appears likely that the blaze will reach the South Fork of the Merced River, the southern perimeter of the 2017 South Fork Fire, which should also slow the progression of the fire.
7:04 p.m. PDT July 8, 2022
Another wildfire is burning in a grove of giant sequoia trees — behemoths that can live for 3,000 years. The Washburn fire was reported at 2 p.m. Thursday July 7 and by 4 p.m. Friday it had been mapped by a FIRIS aircraft at 466 acres. At least 150 acres of the fire are within the Mariposa giant sequoia grove in the south end of Yosemite National Park two miles southeast of Wawona, a community that is under an evacuation order. An evacuation map has been posted and the south entrance to the park is closed.
Preliminary surveys found that in a two year period, 2020 and 2021, almost 20 percent of all giant sequoias in their natural range over four feet in diameter were killed by fire (and neglect) or will die in the next few years. In 2020, 10 to 14 percent of the entire Sierra Nevada population of giant sequoia trees over 4 feet in diameter were killed in the Castle Fire. Early estimates after two fires the following year, the KNP Complex and the Windy Fire, 2,261 to 3,637 sequoias over four feet in diameter were killed or will die within the next three to five years.
Aircraft report that as the activity on the Washburn Fire increased Friday afternoon multiple spot fires occurred near the South Fork of the Merced River and east of Highway 41, some of them 0.7 miles out ahead of the main fire. That river was the south edge of the South Fork Fire that burned 7,563 acres in 2017. Normally a fire would slow down considerably when it encountered a fire scar less than 8 or 9 years old, but the Electra Fire near Jackson, CA burned quite well earlier this week in a seven year old scar. It will be interesting to see what the Washburn Fire will do if it bumps the South Fork Fire footprint.
The National Park Service has conducted four prescribed fires east of the Washburn Fire, in 2003, 2004, 2006, and 2016 for a total of 295 acres. This would have reduced some of the fuel in those areas, which may slow the spread in those treated locations, reduce the wildfire intensity, and the mortality of the giant sequoias. The more recent treatments are the most effective for modifying the behavior of a wildfire.