British Columbia·Video

Wildfire jargon explained: Need-to-know terminology for fire season

Emergency officials use specific terms to clearly and efficiently communicate survival information during fire season — but do you know how to interpret them?

Wildfire or interface fire? Is it contained, held or escaped? Learn the meanings of some key terms below

Wildfire jargon explained

4 years ago
Need-to-know terminology for B.C's wildfire season 1:56

CBC reporter Wil Fundal spoke with B.C. Wildfire Service fire information officer Claire Allen to find out key terminology used by emergency officials during fire season.

Types of fires

A wildfire is an unplanned fire that occurs in a wilderness area, away from people or structures. A prescribed burn that escapes its intended perimeter can also be considered a wildfire.

An interface fire is more of a concern for people. It means a fire could potentially affect man-made structures, while at the same time burning natural fuels such as trees and shrubs. In this situation, a house fire could jump to the forest or vice versa.

Wildfires of note are visible or pose a threat to public safety. You can find up-to-date information on these fires here.

Active wildfires include fires currently under initial attack, observation, patrol or in mop-up stage.

Stages of a fire

Initial attack and suppression efforts are used to attempt to contain a fire.

A fire is considered contained when a fuel-free perimeter has been established around the fire.

"Sometimes, we will say something like '80 per cent contained.' That means we've dug a guard or removed the fuel from 80 per cent of the fire's perimeter," said Allen.

One way firefighters establish fuel-free barriers, or fuel breaks, is by digging down to the mineral soil, a lower layer of soil that contains very little combustible material.

A firefighting recruit during a wildfire training exercise near Merritt, B.C., in May 2019. (Ben Nelms/CBC)

The B.C. Wildfire Service considers a fire out of control when it is not responding to suppression efforts, or if it is growing after initial suppression efforts. Previously this would have been called an expanded-attack fire.

An escaped fire has breached an established control line and remains out of control, following an initial attack. Prescribed burns can also become escaped if they burn beyond their intended area.

"Sometimes, it can look like the fire is out but deep underground things can still be smouldering and you can have underground spread," said Allen.

When a fire is under control but still smouldering, it is being held. Previously, this was called the mop-up stage.

Patrol inspections take place along a control line or portion of a fire perimeter "to prevent escape of the fire after a wildfire has been contained."


When a fire threatens people or property, the B.C. Wildfire Service may make evacuation recommendations to local authorities.

"Life and property is always our highest consideration, as well as the safety of our crews and the communities around us," Allen said.

An evacuation alert signals to residents that they should be ready to leave on short notice. Anyone who leaves during this stage does so voluntarily.

Under an evacuation order, people must leave the area immediately. Evacuation orders are enforced by law enforcement — this may involve police officers going door to door.

During an evacuation order, registering all family members at a local reception centre tells emergency responders that you are safe.

You can find a full glossary on the B.C. Wildfire Service's website.

With files from Ash Kelly and Wil Fundal


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