So far the thunderstorms that Californians were worried about that could ignite even more wildfires did not have much effect in the Bay Area overnight. But lightning strikes were detected in the Sierras along with rain — none, or less than 0.05 inch generally, but some locations received more, as is the nature of thunderstorms.
In the Bay Area there is still a chance of thunderstorms Monday morning, with decreasing chances in the afternoon.
As if firefighters and residents evacuating or battling lightning-caused wildfires in California didn’t already have enough to worry about, another round of dry lightning is in the forecast for Sunday and Monday.
Thunderstorms with little or no rain is what ignited over 500 fires earlier last week. Now scattered or isolated dry thunderstorms could hit northern California and portions of Nevada, Utah, Wyoming, and Colorado through Monday.
Hundreds of new fires are likely if this event pans out. And thunderstorm outflow winds will impact some ongoing fires which would lead to an increase of fire spread/behavior. I hope I'm wrong and this forecast busts. But for now, data points to another big event.
So it’s not just the potential for new fires that that is cause for concern — the strong outflow winds associated with the thunderstorms could greatly increase the rate of spread of the existing fires. It can also put firefighters in even greater danger as the winds can shift 180 degrees very quickly changing the direction a fire is moving, possibly overrunning personnel.
(To see all articles on Wildfire Today about the lightning fires in California, including the most recent, click HERE.)
Check out this video showing the effect the passage of a thunderstorm had on the just-ignited Hennessey Fire August 17 in Napa Valley. That fire has now burned 287,811 acres. The effect of outflow winds is temporary, but a blaze that is suddenly much larger can outstrip the ability of firefighters to quickly suppress it.
Red Flag Warnings are in effect for the northern half of California through Monday evening. The highest threat of dry lightning is Sunday afternoon through Monday morning.
With existing shortages of personnel, equipment, engines, and firefighting aircraft, more fires would put further strain on the systems that are already being managed at the highest planning level nationally, Preparedness Level 5. In PL 5 over 80% of the nation’s incident management teams and wildland firefighting personnel are committed to incidents. Resource orders are being prioritized to fires across California and the west.
Aircraft that can map a fire using infrared imagery have not yet flown all of the large incidents and some maps and acreages are estimates. One of the two mapping aircraft owned by the U.S. Forest Service, N144Z which is the most capable, has not successfully mapped a fire since November 16, 2018 because an avionics issue has not been repaired. The Forest Service has hired privately owned mapping aircraft in an attempt to fill the void.
Below are updates on the largest incidents in California.
LNU Lightning Complex
Updated August 24, 2020 at 7:38 p.m. PDT
Location: North Bay
Counties: Napa, Lake, Yolo, Solano, Sonoma
Administrative Unit: CAL FIRE Sonoma-Lake-Napa
Acres: 350,030. The largest fire in the complex is the Hennessey Fire, 293,602. The Walbridge Fire west of Healdsburg is 54,068, and the Meyers Fire on the coast north of Jenner is 2,360.
Notes: The fires continue to actively burn above the marine layer in the heavy timber and thick undergrowth. Damage Inspection Teams have begun to survey areas where fire activity has diminished and it is safe to do so. The number of destroyed structures reflected may change as teams continue to make progress. Firefighting resources are limited due to the number of fires burning throughout California. Limited visibility due to smoke is hampering aircraft operations. Approximately 77,000 people have been evacuated.
River and Carmel Fires
Updated August 24, 2020 at 7:44 a.m. PDT
Location: Five miles south of Salinas, near Pine Canyon Rd. and River Rd.
Notes: The Carmel Fire 2 miles southwest of the River Fire has burned 6,695 acres and destroyed 37 structures.
Updated August 23, 2020 at 9:31 a.m. PDT
Location: on the coast 10 miles south of Big Sur
Administrative Unit: U.S. Forest Service, Los Padres NF
Structures destroyed: 0
Personnel assigned: 488
Notes: On private land and the Los Padres National Forest, threatening the communities of Hermitage, Partington Ridge, and Lucia. Multiple businesses, communications sites, parks and recreational sites are also threatened. On Saturday crews continued to focus on point protection operations around Hermitage and Lucia to the South, and Partington Ridge and Anderson Peak communications infrastructure to the North. As the threat diminishes these priorities will shift. After more resources arrive the plan will expand to include additional perimeter control operations. The fire was mapped for the first time Saturday night with a fixed wing aircraft. This accurate method is the reason for the large increase in the known acreage.
Updated August 24, 2020 at 7:44 a.m. PDT
Location: 18 miles southwest of Red Bluff
Counties: Tehama, Glenn, Lake, Mendocino, Trinity
Administrative Unit: Mendocino National Forest and CAL FIRE
Structures destroyed: 10
Personnel assigned: 433
Notes: Of the 20 fires in the Complex the two largest are the Doe (136,430 acres) and Glade (13,088 acres). A Structure Damage Assessment Team has been ordered. Limited information is available about this incident.
The Pine Gulch Fire 15 miles north of Grand Junction, Colorado created its own weather very early this morning. It took a combination of several factors, including low relative humidity, an unstable atmosphere, plenty of available fuels (vegetation), and strong outflow winds from a thunderstorm to the north that blew through the fire area between 10:20-10:30 p.m. This caused the fire to increase in intensity and the development of a very large pyrocumulus cloud over the smoke column that created lightning.
Here is the tweet from the National Weather Service that accompanied the image above:
The Weather Service said the lightning lasted for hours and Grand Junction residents could hear the thunder.
Did you hear thunder in Grand Junction last night? That’s right…the #PineGulchFire produced hours of lightning and occasionally the bolts were visible. Here is a video taken at our office. The 3rd largest wildfire in Colorado’s recorded history is full of surprises. #cowxpic.twitter.com/1u4ZlaEtlG
Most of the wildfires in the LNU Complex were very active Tuesday. Based on data from a satellite at 2:06 p.m. the Del Puerto Fire especially increased in size.
(To see all of the articles on Wildfire Today about the lightning-caused wildfires in California, including the most recent, click HERE.)
August 18, 2020 | 7:43 a.m. PDT
Most of the wildfires that started in the San Francisco Bay area in the last three days that escaped initial attack and were already large by Monday evening continued to grow into Monday night, according to heat data collected by a satellite at 2:48 a.m. PDT Tuesday.
At least 16 fires north and south of Livermore are being managed as one “complex”, the SCU Lightning Complex. SCU is the CAL FIRE unit responsible for the counties of Santa Clara, Alameda, Contra Costa, western Stanislaus, and San Joaquin. Some of the names of the individual fires have changed in the last 24 hours, but the largest blazes in the complex are Marsh, Ohlone, Reservoir, and Del Puerto.
Very little detailed information is available about the individual fires.
The Del Puerto Fire, formerly part of the Canyon Zone Fires, is about 10 miles west of Patterson and about three miles northwest of Diablo Grande. With all the name changes the size is not clear, but it is likely 5,000 to 15,000 acres.
The Ohlone and Reservoir Fires southeast of Fremont are adjacent to the Calaveras Reservoir three to seven miles east of the 680 freeway.
Fires that have been grouped into the CZU August Lightning Complex include the Waddle, 5-14, 5-15, and 5-18 Fires, plus other smaller fires. CAL FIRE says they total about 1,000 acres.
Outside of the South Bay area there are many other fires. Further north there are more than 60 fires combined in Butte and Napa Counties, for example.
There are reports that competition for firefighting resources is intensifying as requests placed by some incident commanders are unable to be filled (UTF). Firefighters in some cases are being asked to work double shifts. This situation is unlikely to improve soon, based on the extraordinary heat predicted for this week.
August 17, 2020 | 7:21 p.m. PDT
The map above is an updated version of the one below. The satellite heat data from 2:24 p.m. August 17 shows that the Canyon Zone Fires are growing rapidly toward the southeast and the west.
The Deer Zone Fire west of Los Vaqueros Reservoir was also active on the south side, but not to the same degree. It was mapped at 1,161 acres.
The Marsh Fire east of Milpitas was active at 2:24 p.m. Monday and has burned 1,775 acres.
The three fires oddly named 5-14, 5-15, and 5-18 did not create enough heat to be picked up during the latest satellite overflight at 2:24 p.m. Monday. They are about 5 miles east of Pescadero.
August 17, 2020 | 4:14 p.m. PDT
A rare series of intense summer thunderstorms passed through the San Francisco Bay Area Sunday morning and Monday morning. Some of the cells passed through so quickly there was little chance for precipitation.
Numerous wildfires ignited and while not all of them have been investigated, lightning is the likely cause for many. Combined with winds that accompanied the storms with gusts of 50 to 70, very high temperatures, and a Red Flag Warning, there are so many fires now that they are difficult to track, at least from this writer’s vantage point.
The southern Bay Area has quite a few and there are others in the North Bay and Napa area.
There is competition for firefighting resources. Some of the incident commanders placing orders for aircraft, dozers, engines, or crews are at times being told that a particular order can’t be filled at that time, or there may be a lengthy delay.
From the Washington Post:
In California, the heat resulted in scores of record highs over the weekend including around Los Angeles, the San Francisco Bay area and Sacramento. Early Sunday morning, a bizarre “heat burst” raised the temperature 20 degrees in two hours in Fairfield, about 40 miles northeast of San Francisco. The temperature shot from around 80 to 100 degrees in the hours around sunrise.
The National Weather Service in San Francisco issued an unusually large severe thunderstorm warning that covered more than 7,000 square miles from Monterey Bay to the Bay Area and north into Napa Valley. The office warned of “erratic outflow wind gusts of 50 to 70 mph wind gusts, [and] frequent lightning.” The warning, the largest ever issued by that office, was six times larger than the state of Rhode Island.
“This 20-year forecaster cant recall such a widespread [thunderstorm] event on the heels of such a heat wave,” wrote one meteorologist in the office forecast discussion late Sunday.
We will add to this post later with more details about individual fires.
Originally published at 4:38 p.m. PDT July 23, 2020
In the last 48 hours firefighters have discovered at least 11 lightning-caused fires on the Modoc National Forest in northeast California.
The Caldwell Fire close to Tionesta and southeast of Lava Beds National Monument, has burned 1,500 acres. It was growing rapidly Wednesday afternoon while pushed by winds associated with a thunderstorm.
(To see all articles on Wildfire Today about the Caldwell Fire, including the most recent, click here.)
The Allen Fire in a difficult to access area near Allen Butte was last reported at 800 acres. Smoke jumpers and other crews are working to keep it south of County Road 85.
The Canyon Fire near Canby Bridge has been contained at 234 acres.
At least eight other fires started by lightning have each burned 0.1 to 3.8 acres.
From the Modoc National Forest:
Quick response from firefighting resources in difficult conditions allowed great progress toward containment and control on fires that have been kept small.
The primary fire response strategy for 2020 in Region 5 [California] continues to be aggressive initial attack, to include using local resources from partners. The primary firefighting goal is rapid containment to minimize the number of large wildfires.
Originally published at 3:18 p.m. PDT July 23, 2020
During the last 48 hours thunderstorms with lightning moved across several states in the northwest leading to the possibility of new wildfire ignitions. Most heavily affected were northern and northeast California, southeast Oregon, the south half of Idaho, and western Montana. Precipitation accompanying the cells was spotty.