Research Note

Ember Exposure Pathway Record

The U.S. Fire Administration describes ember deposition, radiant heat, direct flame contact, and convection as wildfire exposures:

Aug 4, 20261 min readBy Dalton Anderson
In this article

Ember Exposure Pathway Record

Exposure system

The U.S. Fire Administration describes ember deposition, radiant heat, direct flame contact, and convection as wildfire exposures:

https://www.usfa.fema.gov/blog/protecting-structures-from-wildfire-embers-and-fire-exposures/

Embers can land on a structure, enter openings, ignite nearby landscape, or ignite nearby fuels such as fences, sheds, and woodpiles. A resulting structure fire can create a new exposure for neighbors.

FEMA's Marshall Fire guide connects building and parcel conditions:

https://www.fema.gov/sites/default/files/documents/fema_rsl_marshall-mat-homeowners-guide-to-reducing-wildfire-risk-through-defensible-space_042025.pdf

IBHS's current Wildfire Prepared program describes research-based property and neighborhood requirements:

https://wildfireprepared.org/

Pathway map

ScaleExample pathways
StructureRoof, vents, gaps, windows, decks, siding, eaves, attachments
ParcelVegetation, mulch, stored material, fences, sheds, vehicles
NeighborhoodAdjacent structures, shared fuels, access, density, wind-driven spread

Boundary

No single roof, vent, distance, material, or designation makes a structure fireproof. Construction, installation, maintenance, weather, topography, neighboring structures, fire severity, and response conditions interact.

The public page is explanatory. Property-specific work requires qualified local fire, building, code, and insurance professionals.

Sources

Follow the evidence.

  1. insurance.ca.gov: commercialguideinsurance.ca.gov
  2. content.naic.org: catastrophe models propertycontent.naic.org
  3. content.naic.org: reinsurancecontent.naic.org
  4. insurance.ca.gov: public wildfire modelinsurance.ca.gov
  5. daltonanderson.ghost.io: ca wildfires insurance crisis expert analysisdaltonanderson.ghost.io
  6. insurance.ca.gov: 07 lasliinsurance.ca.gov
  7. safelease.comsafelease.com
  8. insurance.ca.gov: Order No 2025 1 Approving the California FAIR Plan Association s Request to Issue Assessmentinsurance.ca.gov
  9. ibhs.org: wildfire prepared homeibhs.org
  10. usfa.fema.gov: protecting structures from wildfire embers and fire exposuresusfa.fema.gov
  11. fire.ca.gov: eaton firefire.ca.gov
  12. insurance.ca.gov: release005 2026insurance.ca.gov
  13. insurance.ca.gov: res ins guideinsurance.ca.gov
  14. daltonanderson.net: ca wildfires insurance crisis expert analysisdaltonanderson.net
  15. open.spotify.com: 4TTlp65UK2Dl3zYtgkCklsopen.spotify.com
  16. fema.gov: fema rsl marshall mat homeowners guide to reducing wildfire risk through defensible space 042025fema.gov
  17. insurance.ca.gov: California FAIR Planinsurance.ca.gov
  18. insurance.ca.gov: release079 2025insurance.ca.gov
  19. safelease.com: safelease launches facility insurancesafelease.com
  20. insurance.ca.gov: Sustainable Insurance Strategyinsurance.ca.gov
  21. cfpnet.com: key statistics datacfpnet.com
  22. insurance.ca.gov: release065 2024insurance.ca.gov
  23. podcastrepublic.net: 1494964342podcastrepublic.net
  24. insurance.ca.gov: Insurance surge expanding options for Cainsurance.ca.gov
  25. insurance.ca.gov: 5 residentialinsurance.ca.gov
  26. youtu.be: BUVy0xxL6tgyoutu.be
  27. insurance.ca.gov: release052 2025insurance.ca.gov
  28. fire.ca.gov: palisades firefire.ca.gov

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