Rate of Spread

Rate of spread is the relative activity of a fire in extending its horizontal dimensions. It is expressed as rate of forward spread of the fire front.

When fire moves upslope, the fuel ahead of the flame front is closer to the flame than if the slope were flatter. This set-up "preheats" the fuels. The effects of slope on fire spread become greater as the slope increases.

As fire burns uphill it drafts in fresh air and preheats fuels, increasing rates of spread. Burning embers may also roll down slope contributing to fire spread.

In IFTDSS this is expressed in chains per hour in the Map Studio and reports, in the download it is in meters per minute.

Rate of spread can be displayed in Map Studio.