Which San Diego County burn scars could see debris flows this El Niño winter?
The newest big burn scars are the Henderson Fire (3,260 acres, Oct 2026, Camp Pendleton) and Border 2 (6,625 acres, Jan 2025, Otay Mountain). USGS says burned slopes are most prone to debris flows in the first year.
- Newest large burn scar
- Henderson Fire, 3,260 acres
- Largest recent burn scar
- Border 2 Fire, 6,625 acres
- Riskiest window
- First year after a fire
- Alerts
- AlertSanDiego.org + Genasys Protect
Camp Pendleton, Oct 15–19, 2026 (Cal Fire)
Otay Mountain Wilderness, January 2025 (Cal Fire)
USGS: debris flows typically occur within 2 years
Register phone, text and email; look up your zone
The short version
- The Henderson Fire burned 3,260 acres on Camp Pendleton from Oct 15–19, 2026, per Cal Fire.
- Border 2 burned 6,625 acres on Otay Mountain in January 2025; USGS published a debris-flow hazard assessment for it.
- USGS says burned areas are most susceptible to debris flows in the first year, and most debris flows happen within 2 years.
- Sign up at AlertSanDiego.org and find your evacuation zone on Genasys Protect before the rain starts.
- Warning signs from USGS: rumbling, cracking trees, creeks that suddenly rise, drop or turn muddy.
A strong El Niño winter means more chances for hard, fast rain. On a slope that burned recently, that rain can turn into a debris flow: a fast-moving mix of water, mud, rocks and plants. The U.S. Geological Survey says debris flows can outrun a person and travel well beyond the burn area. Here is where San Diego County's fresh burn scars are, how the warnings work, and what to watch for.
Fire strips away plants and changes the soil so it soaks up far less rain, USGS explains. Even modest storms can then cause flash floods and debris flows on steep slopes, often from short bursts of intense rain, and sometimes in the first storm after a fire. USGS says burned areas are generally most susceptible in the first year, and debris-flow activity typically happens within 2 years. Flash-flood hazards can last several years longer. A 2023 USGS study found that over 98% of 536 debris flows it looked at happened before plant cover grew back to about two-thirds of pre-fire levels.
The burn scars to know for winter 2026–27
| Fire | When | Size | Where |
|---|---|---|---|
| Henderson | Oct 15–19, 2026 | 3,260 acres | Camp Pendleton, started near Basilone and Las Pulgas roads |
| Tusil | May 19, 2026 | 820 acres | Campo Reservation, near I-8 |
| Grade | Jul 31–Aug 4, 2026 | 689 acres | East Grade Road, northwest of Lake Henshaw |
| Range | Jun 30, 2026 | 429 acres | Camp Pendleton |
| Church 2 | Aug 17, 2026 | about 138 acres (Aug 18 report) | Church Road, Campo, east of Lake Morena |
| Border 2 | Jan 23, 2025 | 6,625 acres | Otay Mountain Wilderness |
| Lilac | Jan 21, 2025 | 85 acres | Old Hwy 395 and Lilac Road, Bonsall |
Henderson
- When
- Oct 15–19, 2026
- Size
- 3,260 acres
- Where
- Camp Pendleton, started near Basilone and Las Pulgas roads
Tusil
- When
- May 19, 2026
- Size
- 820 acres
- Where
- Campo Reservation, near I-8
Grade
- When
- Jul 31–Aug 4, 2026
- Size
- 689 acres
- Where
- East Grade Road, northwest of Lake Henshaw
Range
- When
- Jun 30, 2026
- Size
- 429 acres
- Where
- Camp Pendleton
Church 2
- When
- Aug 17, 2026
- Size
- about 138 acres (Aug 18 report)
- Where
- Church Road, Campo, east of Lake Morena
Border 2
- When
- Jan 23, 2025
- Size
- 6,625 acres
- Where
- Otay Mountain Wilderness
Lilac
- When
- Jan 21, 2025
- Size
- 85 acres
- Where
- Old Hwy 395 and Lilac Road, Bonsall
Acreage and dates from Cal Fire incident pages; Church 2 from KPBS, Aug 18, 2026. Checked Oct 29, 2026.
The Henderson Fire is the one people are talking about. An SDSU geology professor emeritus told 10News on Oct 19, 2026 that on the burned hillsides "the plants are dead" and roots no longer hold the soil. We could not find a published USGS or BAER assessment for the Henderson Fire yet, and we could not confirm which off-base neighborhoods sit downstream. Camp Pendleton is federal land, so watch base and County alerts if you live or drive nearby.
How the warnings work
USGS builds hazard maps for many fires. They estimate how likely a debris flow is in each drainage based on burn severity, slope, soil and the peak 15-minute rainfall. The models run for 15-minute intensities of 16 to 40 mm per hour, which is about 0.6 to 1.6 inches per hour. USGS published one for the Border 2 Fire (data last updated June 2, 2025). The maps show the hazard right after the fire, not where mud will end up.
The National Weather Service office in San Diego names burn scars in its warnings. Two examples from March 13, 2025 (outside San Diego County): a Flood Watch said "debris flow are possible near recent burn scars" and listed the Bridge, Line and Airport scars. A Flash Flood Warning for the Airport burn scar in Orange County expected rain at 0.75 to 1 inch in one hour. In San Diego County, NWS issued a Flash Flood Warning for parts of south central county on Oct 10, 2026.
Watch, warning, order
- Flood Watch
- What it means
- NWS: flooding and burn-scar debris flows are possible
- What you do
- Charge phones, pack a go-bag, park facing out
- Flash Flood Warning
- What it means
- NWS: flash flooding is happening or about to
- What you do
- Get to higher ground; don't drive through water
- Evacuation Warning
- What it means
- A possible threat to life and property; evacuation may follow
- What you do
- Be ready to go; leave early if you need extra time
- Evacuation Order
- What it means
- An immediate threat to life and property
- What you do
- Leave now by the route officials give
NWS product names from NWS San Diego bulletins; evacuation terms as defined in San Diego Police Department Procedure 8.20 (Nov 4, 2025).
If heavy rain hits near a burn scar
- 01
Stay awake and listening
USGS notes many debris-flow deaths happen while people are asleep. Keep alerts on and a radio or TV going.
- 02
Leave if officials say so
An Evacuation Order means an immediate threat. Don't wait to see mud.
- 03
If you can't leave, go up
USGS says to move to an upper floor if you must stay, and to stay out of the path of the flow.
- 04
Never cross moving water
Don't walk or drive across a flooding creek or road. See our list of roads that flood.
- 05
Report and check in
Call 911 for anyone in danger. Check the live rain and flood card and our El Niño page for updates.
Is this still right?
We last checked this tip against its sources on October 29, 2026, and we re-research every tip on a schedule. Things in San Diego change, sometimes overnight.
Event dates, times and prices are set by the organizers and can change or sell out. Confirm with the organizer's own page before you plan around them.
This is general information, not legal, financial, tax, medical or safety advice.
KEEP READING
SOURCES
Everything above traces back to one of these. Follow them — if one has changed and we haven't, that's our mistake, not yours.
U.S. Geological Survey · checked 2026-10-29
Definition of postfire debris flows; triggered by short bursts of intense rain; map viewer link.
- PrimaryHazard Assessment FAQ
U.S. Geological Survey · checked 2026-10-29
Most susceptible first year; typically within 2 years; flash-flood hazard can persist several years; 16–40 mm/h design storms.
U.S. Geological Survey (Graber, Thomas, Kean; Geophysical Research Letters) · 2023-10-03
98% of 536 debris flows occurred before vegetation recovered to two-thirds of prefire levels.
- PrimaryLandslide Preparedness
U.S. Geological Survey · checked 2026-10-29
Warning signs and what to do during intense rain.
U.S. Geological Survey via data.gov · 2025-06-02
Data last modified June 2, 2025; metadata Dec 11, 2025.
- PrimaryHenderson Fire incident page
CAL FIRE · 2026-10-19
3,260 acres, started Oct 15, contained Oct 19, 2026.
- PrimaryBorder 2 Fire incident page
CAL FIRE · 2025-01-23
6,625 acres, Otay Mountain Wilderness.
CAL FIRE · 2026
Tusil 820 acres; Grade 689 acres (fire.ca.gov/incidents/2026/7/31/grade-fire/); Range 429 acres (fire.ca.gov/incidents/2026/6/30/range-fire/); Lilac 85 acres (fire.ca.gov/incidents/2025/1/21/lilac-fire).
KPBS · 2026-08-18
About 138 acres, 60% contained at time of report.
10News (KGTV) · 2026-10-19
Quotes SDSU Prof. Emeritus Pat Abbott.
National Weather Service San Diego · 2025-03-13
Example products from 2025; these files are overwritten by newer bulletins.
County of San Diego Office of Emergency Services · checked 2026-10-29
Registration, Genasys Protect partner link, incident 1568.
San Diego Police Department · 2025-11-04
Definitions of evacuation order, warning and shelter in place.
California Department of Insurance · 2026-09-23
Debris-flow exclusions and wildfire exception; hotline 800-927-4357.