Wildfire in California, September 5 to 30, 2024

Name: Wildfire in California, September 5 to 30, 2024
Start: 2024-09-05T09:30
End: 2024-09-30T00:00
Location: California

September 5 to 30, 2024 · NWS SGX · 4 events in 3 counties and zones

Where it happened

Every event with a place to put it; 4 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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Wind
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Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
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The toll

Deaths: 0
Injuries: 34
Property damage: $81 million
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 SGX wrote it up.

Following and during a record heat wave, 3 large wildfires erupted and became out of control burning rapidly. The Airport fire started in Trabuco Canyon in Orange County on the south portion of the Santa Ana mountains. The Bridge fire started in the San Gabriel mountains and spread into Wrightwood and Mt Baldy. The Line fire started in Highland and burned for weeks up the Santa Ana River drainage of the San Bernardino mountains. The wildfires were between 23,0000 and 55,000 acres and caused millions of dollars of damage and expenses to fight.

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 San Diego, CA wrote its last area forecast discussion before the first event at Sep 5, 9:00 AM PST, 30 minutes earlier.

Area forecast discussion, Sep 5, 9:00 AM PST, 30 minutes before

Area Forecast Discussion
National Weather Service San Diego CA
1000 AM PDT Thu Sep 5 2024

.SYNOPSIS...
High pressure aloft will bring very hot weather today and Friday
with high temperatures as much as 15 to 20 degrees above average in
portions of the valleys and inland coastal areas. A return of
monsoonal moisture over the weekend will bring some cooling in the
mountains and deserts, though with little or no cooling in coastal
and valley areas, along with a chance of showers and thunderstorms
in the mountains, deserts, and far inland valleys Saturday and
Sunday during the afternoons and evenings. Drier weather will return
early next week with gradual cooling.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Clear skies prevailed this morning, and it is a hot day already in
most locations. As of 9 AM, Ramona Airport was already 94 F, and
Palm Springs was already 105 F, both up 4 F from 24 hours
beforehand. Excessive heat will continue to build today over inland
areas with the potential for 118-120 in hottest parts of the lower
deserts today and Friday and 111-113 in hottest parts of the
valleys. Coastal areas will be less hot, but even San Diego Airport
could hit 90 at some point in the next few days, and NBM has a 37%
chance of reaching 90 Saturday. If SAN hits 90, that would be the
first time since 19 Oct 2022 when SAN reached 95. Nights will be
warm/hot as well across the region, especially Friday/Saturday
nights as moisture aloft increases and results in more long-wave
radiation reflecting back to the surface, and by Friday night few
stations will get below 70 except in the highest mountains.

High pressure aloft is focused on SoCal and Nevada, the ideal
location for a heat wave here. The upper high will slowly shift
east/northeast towards northern AZ/southern UT by Friday
night/Saturday. That will bring in mid-level moisture from the
southeast and bring mostly afternoon and early evening scattered
thunderstorms in the mountains and deserts. There could be a few
thunderstorms in the valleys/foothills as well, especially given
some surface east flow making it into that area due to low-level
flow from the Gulf of California which will also increase near-
surface dew points in the deserts and lower mountain slopes to help
with instability/CAPE. With the increased moisture, the
mountains/deserts will be cooler, but little/no cooling will occur
west of the mountains, and that westward shift of the thermal
troughing Saturday due to the easterly flow could make it even a bit
hotter in some locations Saturday. Current guidance suggests little
change Sunday, though moisture may start to decrease a bit.

Troughing off the Pac NW should return drier southwest/west flow by
Monday, though there is a lot of variability in the placement and
timing of the trough. We should have cooler weather, though by mid-
week, the uncertainty in the models/ensembles becomes even greater
as about 1/4 of the ensemble solutions in the cluster analysis show
a renewed ridge forming over the West Coast which could potentially
bring more hot weather, though many other solutions have a well-
established trough. As an example of the uncertainty, ECMWF ensemble
MOS shows a 21 deg F range between the highest and lowest members
for high temperatures at Ontario next Wednesday: 85 to 106 F.

&&

.AVIATION...
051600Z...Coast...Mostly clear today and tonight, except for a low
probability (5-15%) of CIGs around southern coastal San Diego County
from 12-15Z Friday morning. If any clouds form, bases would be 300-
600 feet MSL with VIS 0-5SM.

Valleys/Mountains/Deserts...Clear with unrestricted VIS today and
tonight, except for SCT-BKN cumulus with bases around 12000 feet MSL
over the mountains 19-01Z.

&&

.MARINE...
No hazardous marine conditions are expected through Monday, although
northwest wind gusts of around 20 kts are expected in the outer
waters this afternoon and evening.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory from 11 AM this morning to 8 PM PDT Friday for
     Orange County Coastal Areas-San Diego County Coastal Areas.

     Excessive Heat Warning until 8 PM PDT Saturday for Orange County
     Inland Areas-San Bernardino and Riverside County Valleys-
     The Inland Empire-San Diego County Valleys-Santa Ana
     Mountains and Foothills.

     Excessive Heat Warning until 8 PM PDT Friday for Apple and
     Lucerne Valleys-Coachella Valley-Riverside County Mountains-
     San Bernardino County Mountains-San Diego County Deserts-
     San Diego County Mountains-San Gorgonio Pass Near Banning.

PZ...None.

&&

PUBLIC...Maxwell
AVIATION/MARINE...Munyan

In the hours before

Local storm report, Sep 5, 8:57 AM PST, 33 minutes before

Preliminary Local Storm Report
National Weather Service San Diego CA
957 AM PDT Thu Sep 5 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0223 PM     Wildfire         4 ESE San Jacinto       33.77N 116.91W
09/01/2024                   Riverside          CA   Fire Dept/Rescue

            Soboba Road near San Jacinto, the Record
            wildfire burned 517 acres. The wildfire is
            now contained.

&&

AOT

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

4 wildfire. Local standard time, as filed.

Wildfire, San Bernardino County Mountains

When: September 5, 9:30 AM PST to September 30, 12:00 AM PST
Where: San Bernardino County Mountains forecast zone
Injuries: 4 direct, 0 indirect
Property damage: $1.0 million
Reported by: Fire Department/Rescue
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

The Line fire began at 930 am September 5, 2024 at Baseline and Aplin Streets near Highland California. High temperatures on September 5 were 107 to 112F where the fire began. The fire burned north into the Santa Ana drainage due to upslope wind flow. The wildfire grew to 36,000 acres over the next 2 weeks and was finally contained at 44,000 acres in early October. The fire was difficult to contain due to the activity in the remote and thick Bear Creek drainage. The wildfire burned a 98 year old Lookout tower on Keller Peak. The wildfire did severe damage to SR 330 including miles of guardrails and signs which was closed for repairs until November 24, 2024. The fire was contained at the ridge line at Snow Valley to Bear Mountain along SR 18. Arson was determined to be the cause of the fire. The wildfire destroyed 5 structures in Running Springs and injured 4 firefighters. Estimated costs were 14.5 million. The Fire Management Assistance Grant (FMAG) was approved. Air quality index reached 1500 in Big Bear City causing the hospital to close and transport patients. The wildfire experienced a large flare up in Bear Creek on September 29th and burned an additional several thousand acres.

Wildfire, San Bernardino County Mountains

When: September 8, 2:00 PM PST to September 30, 12:00 AM PST
Where: San Bernardino County Mountains forecast zone
Injuries: 8 direct, 0 indirect
Property damage: $10 million
Reported by: Fire Department/Rescue
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

The Bridge fire began at 215 pm PDT September 8th, 2024, suspected to have started by lightning. Excessive heat occurred leading up to the day of the wildfire. The wildfire grew to 35,000 acres on Tuesday September 10th, burning along the ridgeline of the San Gabriel mountains up to 8000 feet MSL and destroying 20 homes in Mt Baldy and 3 in Wrightwood during the evening and night of September 9th. The wildfire created wind gusts up to 40 mph allowing it to become out of control in Wrightwood. There was a Red Flag warning in effect for onshore west winds in the San Gabriel mountains of LA County. The wildfire burned up to to 56,000 acres. 81 structures were destroyed. Defensible space was credited for minimizing the damages to homes. Mountain High ski area recorded the wildfire on September 10th when it burned over the ridge and through the resort. Videos showed the snowmaking (water hydrants) were used to protect structures. 3 resort structures were destroyed along with powerlines but the main lodges were saved.

Wildfire, Santa Ana Mountains and Foothills

When: September 9, 1:20 PM PST to September 21, 12:00 AM PST
Where: Santa Ana Mountains and Foothills forecast zone
Injuries: 22 direct, 0 indirect
Property damage: $50 million
Reported by: Fire Department/Rescue
Coordinates: 33.483, -116.847 (the zone’s center; the record gives no point)

The Airport fire began at 120 pm PDT Monday September 9, 2024 in Trabuco Canyon, at a remote controlled airport facility, following an excessive heat wave where temperatures reached 100 to 112F. The wildfire burned the next 2 weeks across the Santa Ana mountains and SR 74 which was closed. The wildfire reached into western Riverside County, just west of Lake Elsinore. Total acreage was 23,500. Estimated cost of 95 million. There were a total of 160 structures destroyed in Riverside and Orange Counties with 89 of those structures in Orange County. 22 persons, 2 were civilians and the rest firefighters, suffered injuries. A Fire Management Assistance Grant was issued and approved by FEMA through the California.

Wildfire, San Bernardino and Riverside County Valleys - the Inland Empire

When: September 10, 12:00 AM PST to September 21, 12:00 AM PST
Where: San Bernardino and Riverside County Valleys - the Inland Empire forecast zone
Property damage: $20 million
Reported by: Emergency Manager
Coordinates: 34.293, -116.086 (the zone’s center; the record gives no point)

The Airport fire began at 120 pm PDT Monday September 9, 2024 in Trabuco Canyon of Orange County (remote control airport facility) and then burned to the Santa Ana mountain crest and Santiago Peak and reached into western Riverside County on September 10th, 2024. The wildfire caused major damage in the small town of El Cariso village and prompted evacuations into Lake Elsinore. Riverside County reported 55 structures destroyed and 7 homes severe damaged. There were about 50 vehicles that were burned and damaged, which many were historical models and featured in movies. Over 150 structures were destroyed in including 119 homes due to the Airport wildfire between Orange and Riverside counties. Fire Management Assistance Grant (FMAG) was awarded for the Airport wildfire with total damage estimated at 95 million. Reports indicated that up to 400 million in claims were filed.

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 2024 Every state in 2024 This day in weather history Warnings in California, September 2024

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: 1218710, 1218727, 1218724, 1219526.