Fire disasters

Wildfire

Fires start when an ignition source is brought into contact with a combustible material (e.g. peat, shrub, trees) that is subjected to sufficient heat and has an adequate supply of oxygen from the ambient air. A wildfire is any uncontrolled fire that occurs in the wilderness, wildland, or bush. Other names such as wildland fire, forest fire, brush fire, vegetation fire, grass fire, peat fire, bushfire, and hill fire are commonly used. Fires in forested areas can move at speeds of 10.8 kilometres per hour (7 mph), while grass fires have been recorded at up to 22 kilometres per hour (14 mph).

Nine out of ten wildfires are reportedly caused by some human interaction, like arson; others are caused by natural events such as lightning strikes, volcanic discharges, etc. Wildfires differ from other fires only by their extensive size; the speed at which it spreads out from its original source; its ability to change direction unexpectedly; and to jump gaps, such as roads, rivers and fire breaks.

Weather patterns such as heat waves, droughts, and climate changes can also dramatically increase the risk and alter the behavior of wildfires. Years of precipitation followed by warm periods have encouraged more widespread fires and longer fire seasons.

Fire intensity also increases during daytime hours. Burn rates of smoldering logs are up to five times greater during the day due to lower humidity, increased temperatures, and increased wind speeds. Sunlight warms the ground during the day and causes air currents to travel uphill, and downhill during the night as the land cools.