How the EmberCheck score is calculated
EmberCheck gives your home a wildfire risk score that changes with the weather. This page explains what goes into that number and the things it cannot tell you.
What the score is
A number from 0 to 100 for the monitored point nearest your address. It is recalculated through the day as new conditions arrive, so it moves with the weather rather than describing a fixed characteristic of your property. Most of it reflects conditions that change day to day: how dry the fuels around you are, how hot and windy it is, and whether a fire is already burning nearby. The rest reflects things about the property that change slowly.
The score is an index for ranking days and places, not a probability. A 74 does not mean a 74 percent chance of anything. It means today at this monitored point ranks high against the same point on other days, and against other addresses under the same model.
That is the difference between EmberCheck and a hazard map. A hazard map describes the long-run character of a place and says the same thing in January that it says in September. EmberCheck answers a narrower question: is today unusual here.
What it is computed from
Four kinds of information: measured weather and fuel-dryness conditions at the property, the terrain it sits on, the vegetation around it, and whether fire is already burning nearby.
In California, Oregon, and Washington, the score adds a small amount, 2 to 8 points out of 100, when fine-particle smoke measured in the same county within the last six hours passes a set level. A reading is not always available, and a location without one is scored as if the air were clear. Outside those three states, smoke is not part of the score.
In California, the score also adds points near places where past fires have destroyed buildings, using state damage records within about 19 miles of the address. Those records come from California's fire agency, so this applies almost only in California.
We publish those categories, not the recipe. The specific products behind each one, and the weighting, combination and thresholds that turn them into a number, are not published.
Two things are deliberately missing. We do not score your defensible space or how your home is built, because neither can be measured remotely from satellite or federal data, and pretending otherwise would be guessing at the two things you most control. We also do not use your insurance history or any personal data.
Computed, not generated
The score is the output of a fixed formula applied to measured readings. Those readings come from instruments and satellites operated by government agencies, the same public observations fire agencies work from. The same formula is applied at every address we score.
No language model writes this number. No part of it is invented, and nothing is filled in by inference when a reading is missing: when data we rely on is unavailable, the product says so rather than estimating around the gap.
Where it works, and where it is only watched
EmberCheck monitors wildfire conditions across 11 western states: California, Oregon, Washington, Arizona, Idaho, Montana, Nevada, New Mexico, Utah, Colorado, and Wyoming. Coverage describes where we monitor. It is not, on its own, a promise of detection or accuracy for any specific place or fire.
Scoring runs the same way in all 11 states.
What EmberCheck does not do
- It is not an evacuation system. Evacuation orders come from your county and your fire agency. Follow them, and follow them ahead of anything on this site.
- A low score is not an all-clear. Destructive fires start on ordinary days.
- It does not know your house. Defensible space and home hardening are the two biggest things you control, and neither is in the score.
- It is not insurance advice. It does not determine whether you can get a policy, or what you will pay for one.
- When a data feed goes down, we say so. An empty fire-activity panel means we have no current detection data, not that there are no fires near you.
For live information during an active fire, Watch Duty is free, fast, and run by people who do it well. We would rather point you there than pretend to be it.
Attribution
These sources are named because their licences require attribution, and because EmberCheck already credits them where their data is shown.
- NASA FIRMS: satellite fire detections
- NIFC: confirmed wildland fire incident records
- CAL FIRE: damage inspection (DINS) records
This is an attribution list, not a description of the model. The weighting, combination and thresholds are not published.
Corrections
If you find an error on this page, tell us. We will fix it and say what changed. See also where EmberCheck works and how PRECEDE works.
Methods last updated September 2026 · Model v13-lightning