All it takes is a spark

Last year was one of the most devastating fire seasons our province has ever experienced. Drought conditions and a series of heat waves led to widespread fire activity, peaking much earlier than usual. More than 1,600 fires burned nearly 8,700 square kilometres of land, and 67 of those fires were bad enough to be classified as “wildfires of note” by BC Wildfire (highly visible fires that threaten public safety). 

The frequency and severity of wildfires is only getting worse. It probably comes as no surprise that climate change is one of the main forces driving this trend—it causes droughts, reduces snowpack, increases lightning strikes, and ultimately extends the fire season. Because of climate change, we can only expect hotter, drier summers and bigger, more destructive wildfires. At the same time, as our population rises, community developments continue to encroach on forests and wildlands, placing more people in harm’s way. That’s why it’s critical to understand how wildfires start, how you can protect yourself from them, and what to do when they occur.

How wildfires starts

Though classified as natural disasters, half of our province’s wildfires result from human causes, like unattended camp and debris fires, discarded cigarettes, and arson. The other half are started by lightning; the heat released from one strike is often enough to ignite trees and other fuels. (In 2020, 59% of fires were caused by people and 41% by lightning.)

Between May and September, when the weather turns lush vegetation into dry, flammable fuel, all it takes is a spark for a fire to ignite. But in order for a wildfire to burn, three conditions must be present: heat, fuel, and oxygen. We call this the “fire triangle.” 

Fire is the outcome of a chemical reaction known as combustion, which occurs between oxygen and fuel that’s been heated to the lowest temperature at which it will ignite (its flashpoint). Heat is responsible for the initial ignition of a fire. By warming the air, drying out and preheating nearby fuel, heat also enables a fire’s spread. For it to grow, though, fire needs combustible material, such as trees, grasses, brush, or even unmitigated homes. The moisture content of these fuels determines how easily they will burn, and the amount of fuel in a fire’s surroundings dictates its intensity. Air supplies fire with the oxygen it needs to survive. When fuel burns, it reacts with the oxygen in the air, releasing heat, gas, smoke, and embers. A fire can only occur when all three components react together, but this “fire triangle” can be extinguished if at least one of them is removed from the equation.

How wildfires grow

Wildfires can consume thousands of acres of land in no time at all. Their rolling flames travel up to 23 kilometres an hour, which converts to about a four-minute-mile pace (much faster than the average human can run). But the intensity and movement of a wildfire depends on three factors: fuel, weather and topography. 

Fire can spread quickly in forests with dense and continuous fuels. In these types of environments, they spread rapidly along the surface and then up into the trees. They can cast off burning pieces of debris called ‘embers,’ which can be carried ahead of the fireline by up to two kilometres. These embers may land on trees or unmitigated homes and create a multiple-fire situation (a 2019 insurance study in the United States found that of all homes and buildings that ignite in a wildfire, embers alone account for up to 90 percent). The composition of fuels, like moisture levels and density, influence how quickly a fire will spread and how much of an area will burn. If fuels have a low moisture content (meaning they are very dry), a fire will burn faster and more intensely because it doesn’t have to expend its heat in order to eliminate water. 

Wind, temperature, and humidity play a major role in fire behaviour. Wind fans fire with oxygen, causing it to spread at a faster rate. High temperatures and low humidity dry out fuel sources, making them easier to ignite and faster to burn. 

A landscape’s topographical features, like slope, aspect and elevation, also affect fire movement. Wildfires spread faster uphill because as hot air rises, it preheats fuels further upslope and causes them to ignite quickly as the fire climbs. Elevation often determines the temperature and moisture level of fuels. For example, south-facing slopes at lower elevations get more sunlight, which makes those fuels warmer and drier, leading to more intense wildfires. 

How wildfires spread within communities

The common misconception about wildfires is that they start in forests, spread through tree canopies, and eventually reach communities, engulfing them in a wall of flames. In most cases, wildfire disasters begin with ‘surface fires’—fires that burn along the ground, in dead grass, dry shrubs, and accumulations of leaf, needle litter, and other flammable debris. As surface fires grow, they release embers, which then can cause rapid structure-to-structure ignitions between sheds, homes, and businesses. This means you don’t have to live near a forested area to be affected by wildfires.

As wildfires spread toward homes, they often ignite other flammable objects in their path by direct flame. Breaks in this path, especially close to your home, can help reduce this threat. In addition, radiant heat from a wildfire can melt vinyl siding, ignite your home and even break windows. This can be caused by the extreme heat of flames within 30 metres of the home, or from vegetation burning directly adjacent to the structure.

How to protect yourself from wildfires

There are those things we can’t control, like the weather and how the climate is affecting wildfire behaviour. But we can control the vulnerability of our own properties. By taking action and creating a FireSmart property, you will dramatically increase the resistance of your home and property to damage caused by wildfire. 

FireSmart’s homeowners manual empowers homeowners with critical information, like how wildfires grow and spread, how to spot hazards in and around a structure, and how to store fuel sources at a safe distance.

The FireSmart BC Landscaping Guide includes an extensive list of FireSmart plants, instructions on how to recognize the characteristics of other garden-favourites not yet on the list, and expert insights on making vegetation a barrier that keeps embers from igniting your property. 

The FireSmart BC Plant Program provides gardeners, landscapers, and suppliers with the knowledge and tools to help mitigate wildfire risks where they live and work. 

If you are concerned about your neighbourhood’s fire risk, ask local authorities, the planning department, or fire department how they are integrating FireSmart principles into their plans. You can also reach out to your Local FireSmart Representative to assess your home and enroll your neighbourhood in the FireSmart Canada Neighbourhood Recognition Program (FCNRP).

In the event of a fire, make sure to call your local fire department immediately (911) and notify the BC Wildfire Service by dialling 1 800 663 5555 (or *5555 from a cell phone). Then, if you have time to do so safely, take the following actions:

  • Review your evacuation plan for your family and pets. 
  • Have your “grab-and-go bag” (emergency kit) ready and stocked with cash, portable radio, prescription medications, eye glasses, change of clothes, pet food, flashlights and batteries, etc. Make sure your phone numbers, insurance information and other important documents for your go bag are current. 
  • Turn off air conditioning.
  • Turn off your home water and electricity 
  • Close all doors, garage doors, and windows. If weather seals or doors have gaps, seal them with duct tape.
  • Move combustible material, like curtains and furniture, away from windows.
  • Move all combustibles, like firewood, lawn furniture, etc., away from your house.
  • Prepare your vehicle for a quick getaway by leaving it positioned facing out of the driveway.
  • Keep car windows closed and have what you need to take in your vehicle.
  • Make sure your ladder is accessible to emergency responders and outside your home or shed
  • Evacuate your family and pets to a safe location.

To make things easier, divide tasks amongst family members. And make sure each person knows their role and which actions to perform in the event of a fire.

Wildfires don’t just threaten property, natural resources, and human lives, they also affect  air quality, increase local temperatures, release vast amounts of carbon, and kill off vegetation capable of filtering future emissions out of the air. That’s why an understanding of how wildfires behave, how you can protect yourself from them, and what to do when they occur is the best line of defence for your home, community, and the environment. By undertaking FireSmart activities, all of us can play a critical role in mitigating wildfire risks around our homes and properties, ultimately decreasing the intensity and slowing the spread of wildfires. 

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