Fire Values Guide
Fire Size & Area Classification
How an incident's burned area is measured and described — from a spark's first hectares to a province-spanning complex.
What "hectares" tells you
The size of a wildfire is reported in hectares (ha). One hectare is a square 100×100 metres — roughly two football fields (about 2.47 acres). It's the standard unit BC uses because it scales sensibly from a fraction of a hectare for a lightning strike to tens of thousands of hectares for a major complex. Size is updated daily as the fire perimeter is re-mapped by aircraft and satellite, and it reflects the area burned, not how intense the fire is.
Common size classes
How size is measured
During the first hours and days a fire's size is a professional estimate from aerial reconnaissance. Once a controlled GPS perimeter is flown, the area is calculated precisely from the mapped boundary and reported to the nearest hectare. Some incidents (a "complex") report a single combined size for several adjacent fires managed together. Size changes are normal — a fire can grow, be corrected down after an over-estimate, or stay static once fully contained.
Size vs. intensity — a common confusion
| Term | What it measures | Key question |
|---|---|---|
| Size / Area | How much land has burned (ha) | "How big is it?" |
| Rate of spread | How fast the leading edge advances | "How fast is it moving?" |
| Intensity (FWI / head fire) | How hot / how much energy it throws | "How hard is it burning?" |
A fire can be small but fierce (steep, dry, windy slope) or large but calm (a slow-burning mop-up). Size alone never tells you the full risk — pair it with the Fire Weather Index and Fire Behaviour.
Where you see size in Fire Aware
On the Detection Map and Fire Dashboard, each active fire's size (sizeHa) is listed under the fire's details. On the home page, the "Active Fires" widget totals all active fire areas and breaks them down by status. Circled "hectares" figures are official BCWS-reported values where available.
Data Source
Size and area values are provided by the BC Wildfire Service (Incident Management) and the national Canadian Wildfire Information System (CWFIS) fire polygon data. Estimated vs. GPS-mapped figures are reconciled as they become available.
How Size Is Measured and Reported
Fire size in BC is reported in hectares, calculated from aerial mapping of the fire perimeter using GPS and infrared imagery.
Size classes run from A (less than 0.01 ha) to E (over 1,000 ha). A fire can double in size between observation flights — the time of last measurement matters as much as the number. Historical size distributions by region are available on the Fire Records page; the Detection Map shows the current perimeter for active fires.