Read this first
A probability is not a prediction — and it is not live.
Probability assessment asks how strongly a place resembles the places where fire has
historically occurred. It is an archival exercise: dated, versioned, and revisited — never a
tracker of active fires, and never the sole basis for emergency, insurance, or land-use
decisions. This platform deliberately does not track live fire response.
Step one · the evidence
Start from the historical record
The honest anchor for any probability statement is what has already happened.
Before touching a model, assemble the record and interrogate it.
Fire perimeterswhere & how often
Map every recorded burn. Recurrence is the strongest single signal —
fire-prone ground tends to stay fire-prone, because the conditions that made it burn persist.
Ignition recordswhere fires start
Starts cluster along human corridors — roads, communities, infrastructure.
Ignition density tells you where the sparks are, independent of whether they grew.
Frequency as base ratethe anchor
Fires per unit area per decade, from the record itself, is your base rate.
Every adjustment you make afterward should be explainable as a departure from it.
Vintage & coveragehonesty check
State the record's time span and its gaps. A quiet decade in the data can
mean quiet ground — or missing reports. The assessment inherits every weakness of its record.
Step two · the modifiers
Layer on the environment
History says where fire has been welcome; the landscape says whether it still is.
For each factor, the question is the same: does this raise or lower the resemblance to past fire ground?
Fuelsthe carrier
In Hawaiʻi the dominant carrier is dry invasive grass. Ask what fraction of
the ground is fine fuel, and how cured it is right now versus the record's typical state.
Drynessthe slow variable
Drought loads the landscape over weeks and months. Treat it as the slow
dial that moves everything else — the same fuels behave differently at different dryness.
Windthe spread driver
Wind rarely starts fires; it decides what they become. Consider prevailing
patterns and terrain alignment — wind moving upslope with the fuel is the dangerous geometry.
Terrainthe amplifier
Slope preheats the fuel above the flame; aspect decides which faces cure
first. Terrain doesn't create risk — it multiplies whatever the fuels and weather supply.
Exposurethe stakes
Where the wildland meets people, the same probability matters more. Keep
likelihood and consequence distinct in the analysis — but present them together.
What to leave outdiscipline
Live detections, active incidents, response status — operational feeds
belong to monitoring, not probability. Mixing them in turns an archive into a false forecast.
Step three · the combination
Combine transparently, or not at all
However you weigh your factors, the method — not the number — is the product.
A few practices separate a defensible assessment from a black box:
Few, named factors
A handful of drivers you can defend beats dozens you can't. Every factor
should have a stated source and a stated reason for being there.
Explicit weights, versioned
Write the weights down, date them, and version every change. A score that
can't say which weighting produced it is not evidence — it's an opinion with decimals.
Carry the breakdown
Every assessed value should travel with its component contributions, so a
reader can see why — and argue with the parts rather than the whole.
Handle gaps honestly
When a factor has no data somewhere, say so and renormalize across what
remains — never let silence quietly drag the result toward zero, and never invent a value.
Invite expert review
Weightings are hypotheses about fire behavior. Publish them for the people
who fight and study these fires, and expect to revise.
Bands, not decimals
Communicate in a few labeled bands. Two decimal places imply a precision
the underlying record cannot support — banding is the honest resolution.
Step four · the artifact
Treat every assessment as legacy
A probability assessment is a dated document, not a dashboard. Archive each
run with its inputs, weights, and vintage; revisit on a schedule, and when the record grows.
The value compounds in the archive — the comparison between last year's assessment and this
year's is often more informative than either alone. When someone asks "what's the risk right
now," the answer is the monitoring page; when they ask "where
should mitigation go," the answer is the archive.
Working here
The evidence base on this platform
Everything above can be conducted with the historical layers already in the
atlas: fire perimeters with year filtering, ignition density, fuels and
landcover, terrain, and land exposure — with area reports that
assemble the record for any drawn boundary, and the open API for anyone
building their own assessment on top of the same evidence.