Our fire season not over yet

Our fire season not over yet

21 July 2008

published by www.lompocrecord.com

USA — You may have noticed that there is less news about wildland fires lately. The “Gap Fire” is extinguished, as are most of the other large fires north of us, with the exception of the “East Basin Fire” in Monterey County. Let me assure you that this is just the calm before the storm. Our fire season for Central and Southern California usually begins in August or September and lasts sometimes into November.

Wildland fires become critical when a confluence of circumstances occur. These circumstances include weather, fuel and location. The weather affects wildland fires by how it interacts with the fuels and the fire itself.

When the temperatures are high and the relative humidity is low, the moisture level in the fuels (brush, grass, trees) is diminished. As the fuel moistures are lessened, they become more susceptible to ignition. The greater the disparity between temperature and relative humidity, the more critical the fire weather becomes. Once a fire begins, the weather continues to affect the fire by the strength and direction of the winds. As the wind pushes the fire, the hot dry air pre-heats the fuels in front of the fire, lowering their ignition temperature even more.

Fuels affect the fires in many different ways, but I’ll give you the short course. Fuels are either alive or dead. Dead fuels absorb and retain moisture from the surrounding air, which is relative humidity. If the air is dry, it actually absorbs the moisture from those dead fuels. Live fuels get the moisture from the ground. As temperatures increase, the live fuels lose moisture through evaporation faster than they can pull it from the ground. As you know, dry wood is easier to burn than wet wood. This is fuel moisture.

Fuels also affect the fire by their size and configuration. If fuels are closely packed together, they add a continuous supply of fuel to the fire. Compacted fuels help the fire to build in energy output. Fuels that are separated by space allow the fire’s energy to dissipate into the air. The size of the fuel also determines the fire’s energy output and also dictates how easily it can be ignited. Twigs are easier to light with a match than a log because they’re small and have less fuel moisture. A log is more difficult to ignite but once a log is burning, it produces a substantial amount of heat.

In our area of the Central Coast, fire weather becomes critical when temperatures are above 85 degrees, the relative humidity is less than 20 percent and winds are greater than 15 mph. When the weather matches or exceeds these parameters, our fire department becomes hyper-vigilant and may add additional staff in preparation for a fire. We will also fly a red flag from our flagpoles and place placards on our vehicles stating “Red Flag Fire Alert.”

In Lompoc, the announcement of a Red flag Fire Alert is mostly informational, as an advisory to the public to be extra cautious. In other areas of the county, the initiation of this alert may cause road closures, fire patrols and activation of specialized fire watches.

The location of a wildland fire is critical because of the danger it creates to the public, to developments and to natural or historic areas. When a fire threatens a community, obviously, there is greater importance and urgency placed upon it then if it is threatening uninhabited wildland areas.

The Lompoc Fire Department has had personnel and equipment out fighting these wildland fires this year since they began. Our personnel and equipment are still out on the East Basin Fire. The knowledge and expertise they gain from these fires is invaluable to you and our department. Training is good but actually experience is better. Our firefighters are out there now, gaining the knowledge and experience that will help them fight our fires when they get here. Our fire season is just about to begin and our Lompoc firefighters are ready.

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