Wildfire in California, September 1 to 30, 2020

Name: Wildfire in California, September 1 to 30, 2020
Start: 2020-09-01T00:00
End: 2020-09-30T23:59
Location: California

September 1 to 30, 2020 · NWS STO · 4 events in 4 counties and zones

For the month of September wildfires continued to burn across northern California. The August Complex is the largest fire in California history, and is spread across the county warning areas of weather forecast offices Sacramento and Eureka.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 4

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS STO wrote it up.

For the month of September wildfires continued to burn across northern California.

The August Complex is the largest fire in California history, and is spread across the county warning areas of weather forecast offices Sacramento and Eureka. One fatality and injury occurred on August 27 at the August Complex due to a vehicular accident, many structures were destroyed or damaged. The August Complex finally becomes fully contained by November 15, 2020.

The LNU and SCU complexes are mainly within the county warning area of weather forecast office Monterey; however, both fires spread into Sacramento's forecast area.

The LNU Complex caused significant damage in Solano County, including 2 fatalities, the evacuation of Vacaville and Fairfield, and the closure of I-80. Yolo County was also affected by the fires and had evacuations and road closures. 3 Fatalities occurred in Napa County. It has been difficult to find detailed data, but there were 5 injuries that occurred, 4 civilian and 1 first responder. The LNU Complex finally becomes fully extinguished by October 1, 2020.

The SCU Complex covered large swaths of land over Santa Clara, Alameda, Contra Costa, San Joaquin, Merced, and Stanislaus counties. Per the last CalFire incident update, 6 injuries occurred, 4 were first responders and 2 were civilian. The fires caused significant damage over the area. The SCU Complex finally becomes fully contained on October 1, 2020.

Finally, the North Complex, spanning portions of Plumas and Butte counties, was also started by lightning on August 17 at 8AM PST. Fire activity occurred for the month of August, but extreme fire growth happened during the month of September due to a strong offshore wind event. Per the US Forest Service there were 16 fatalities and 2,455 structures destroyed. As of November 29, the date when this is being prepared, estimated containment is expected to occur on November 30.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Sacramento, CA wrote its last area forecast discussion before the first event at Aug 31, 1:08 PM PST, 10 hours 52 minutes earlier.

Area forecast discussion, Aug 31, 1:08 PM PST, 10 hours 52 minutes before

Area Forecast Discussion
National Weather Service Sacramento CA
208 PM PDT Mon Aug 31 2020

.SYNOPSIS...
Smoke and haze from wildfires will continue to impact air quality
and temperatures for the next several days. Dry weather and above
average temperatures expected through the week. Near record heat
possible Labor Day weekend.

&&

.DISCUSSION...
Another hazy afternoon is noted across the Valley due to smoke from
numerous wildfires across Northern California. Some breezy north
winds have been realized this morning and afternoon in the vicinity
of the northern Sac valley with Redding reporting some gusts up to
around 30 mph. These winds have helped keep much of Shasta and
Tehama Counties smoke free with better air quality than locations to
the south.

A shortwave drops into the Four Corners region overnight before high
pressure builds in over California tomorrow during the day. Some
north winds continue in the northern Valley and along the coastal
range tonight and tomorrow, with some locally breezy east winds in
the Sierra and Southern Cascades. With the exception of the Delta
Breeze, lighter winds are expected for the rest of the week due to
the influence of high pressure.

Triple digit temperatures are expected in the northern Sacramento
Valley tomorrow, with highs generally in the 90s for the rest of
Valley locations. Smoke may be similar tomorrow as it was today with
the better conditions in far northern California due to the
continued northerly winds. For the rest of the week, confidence is
high for slightly above average temperatures but how hot we get may
be limited to how dense smoke is over locations. The hottest
locations continue to be the north end of the Sacramento Valley. Dry
weather remains.

&&

.EXTENDED DISCUSSION (Friday THROUGH Monday)...
Persistent and strong upper level high pressure builds over the
area this weekend, becoming centered over NorCal on Monday. This
will result in a warming trend through the extended with record
breaking heat possible Sun/Mon as 850 mb temps rise into the lower
30s deg C. Smoke may continue to impact the area and temperatures
this weekend. Dry weather expected continues through the holiday
weekend.

&&

.AVIATION...
HZ/FU will bring MVFR and isolated IFR conditions to the southern
terminals this afternoon with some improvement this evening. VFR
conditions expected for the northern terminals. Breezy northern
winds diminish overnight falling below 12 knots. Breezy southerly
wind gusts up to 30 knots possible in the Delta after 00z.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&

Event by event

4 wildfire. Local standard time, as filed.

Wildfire, Northern San Joaquin Valley

When: September 1, 12:00 AM PST to September 30, 11:59 PM PST
Where: Northern San Joaquin Valley forecast zone
Reported by: Fire Department/Rescue

The SCU Complex started on August 16 and eventually becomes contained on October 1, 2020. It covered Santa Clara, Alameda, Contra Costa, San Joaquin, Merced, and Stanislaus counties which span the county warning areas of Monterey and Sacramento offices. This fire ends up burning a total of 396, 624 acres, destroying 136 structures and 86 minor structures, and damaging 26 structures. 6 injuries were reported, 4 of which were first responders and 2 civilian; however, detailed data for injuries have been hard to come by. Finally, evacuations and road closures occurred. The majority of this fire complex burned in Monterey's county warning area.

Wildfire, Mountains Southwestern Shasta County to Western Colusa County

When: September 1, 12:00 AM PST to September 30, 11:59 PM PST
Where: Mountains Southwestern Shasta County to Western Colusa County forecast zone
Reported by: Fire Department/Rescue

The August Complex was started by lightning on August 16 and 17, initially over the Mendocino National Forest. Since then, the fire has grown extensively and currently spans two National Weather Service county warning areas, Sacramento and Eureka. Counties that have been affected are Tehama, Glenn, Colusa, Lake, Trinity, Mendocino, and Humboldt counties. The fire becomes fully contained on November 15 and ends up burning 1,032, 648 acres. It destroyed 54 structures and damaged 6 structures. 1 fire fighter fatality and an associated injury occurred via a vehicular accident while on the line in Eureka's forecast area.

Wildfire, Southern Sacramento Valley

When: September 1, 12:00 AM PST to September 30, 11:59 PM PST
Where: Southern Sacramento Valley forecast zone
Reported by: Fire Department/Rescue

The LNU Complex started on August 17 and will eventually become contained on October 2, 2020. This fire ends up burning a total of 363, 220 acres, destroying 1491 structures, including an NWS COOP site, and damaging 232 structures. For Solano County, 42,00 acres were burned, 309 homes were destroyed, 854 structures were damaged, and 1,426 utility poles were replaced. Many evacuations occurred, including larger sized populations such as Fairfield, Vacaville, and Travis Air force Base. Multiple road closures happened as well, including Interstate 80 for a brief period. Finally 5 deaths, which are detailed and recorded as separate events, and 5 injuries happened because of the fire. Injury information has been hard to come by with the latest information being 4 civilian and 1 first responder injury.

Wildfire, Northeast Foothills/Sacramento Valley

When: September 1, 12:00 AM PST to September 30, 11:59 PM PST
Where: Northeast Foothills/Sacramento Valley forecast zone
Reported by: Fire Department/Rescue

The North Complex, spanning portions of Plumas and Butte counties, was also started by lightning on August 17 at 8AM PST and continued through the month of September. Extreme fire growth happened just after Labor Day due to a strong offshore wind event. Per the US Forest Service there were 16 fatalities and 2,455 structures destroyed. As of November 29, the date when this is being prepared, estimated containment is expected to occur on November 30.

What these are

Wildfire: A fire burning in wildland vegetation, with its acreage and damage where known.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2020 Every state in 2020 This day in weather history Warnings in California, September 2020

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 922722, 922723, 922724, 922726.