When it is deemed by Ottawa Fire Service that the grass, bush, and brush is at a point where it is getting very dry (we call this browning), it is a concern for two main reasons:
1) Rapid Fire Spread – not only burning fields, brush and forests, but more dangerous is the rapid fire spread towards buildings and homes.
2) Ignition Probability – The likelihood of a float away spark from a campfire for example, starting a fire is greatly increased when the foliage is dry.
Understanding the Spring Burn Ban
Commonly, year after year, the Ottawa Fire Service will put a burn ban in around Springtime. This may confuse people as well, as they see that the ground is soaked, the roots are green, and spring has sprung!
What is not seen is that the tips of grass and foliage are still brown from winter. This means that if a brush/grass fire does occur, it “rolls” across the field incredibly fast, and can and has approached buildings, homes and barns.
The other hazard in the spring and the reason why burn bans are in place is quite simply that we cannot get our fire trucks and apparatus into the fields and bush to fight the fires as they are heavy and literally, sink in the mud.
Life Safety Concerns:
Many people don’t realize that Fire Bans can be put in place even when the foliage, grass and brush don’t seem to be too dry. However, the Life Safety of Firefighters is of concern when temperatures reach the 30⁰ mark and then add humidex that may push into hi 30’s or over 40⁰ Celsius and it puts our Firefighters at risk. Fighting fires in this heat, with 70 lbs of gear on can be extremely dangerous.
So, when is a Ban Lifted?
It all has to do with the opposite of “browning”. We need to see the foliage “green up” from the roots to the tip of the grass as an example, we cannot usually lift the ban before that. This usually can only happen with a good 3-5 days of steady rain. This is where sometimes some people get confused as they experience a day or two of thunderstorms or showers and they believe that should green the grass and the ban can be lifted. This is typically not the case. We don’t monitor the rain; we monitor the grass.