Already well into the forest fire season, Yukon's fire managers and crews are being kept busy with this year's bout of wildfires. The fire danger is already at or above average summer conditions and the lightning season has started.

"Just a few days of hot, dry weather and some wind can send the danger to extreme," warns Dave Milne, Fire Prevention Coordinator with DIAND Fire Management.

DIAND relies to a large extent on weather expertise and high-tech tools to help them predict and manage forest fires. "Through the summer we have a full-time weather forecaster on staff who conducts daily briefings," explains Milne, "and we are constantly receiving data from monitoring stations throughout the Yukon."

Milne pulls up DIAND's complex map database on a large monitor, and demonstrates how a number of variables can be integrated and displayed. Advanced geographic information systems (GIS) bring DIAND and Environment Canada's data sets together to produce mapping tools that guide Yukon's fire managers.

"Regardless of all the high tech tools, computer modeling and aircraft available, it's still the team of firefighters that we rely on to fight the fires," Milne emphasizes. "Putting the fires out is often a mix of skilled firefighting personnel, the right equipment and cooperation with Mother Nature."

He points to a map with current temperatures, and another that shows a moisture index. By integrating these and other variables such as occurrence of lightning strikes, Milne can get a better picture of actual conditions that might contribute to a forest fire in a particular region.

He lays out a colourful map that depicts fifty years of forest fires. "The territory's lightning belt extends mostly down the Tintina Trench, from the Dawson region southeast along the Klondike Highway and past Faro and Ross River to Watson Lake." Though it's clear from the map that some of the territory's fire management regions experience more forest fires than others, the splotches of colour don't really show an obvious pattern.

Next he rolls out an ecoregion map. Instead of roads, political boundaries or regional districts, the map delineates between regions with distinct landforms, soils, climate and vegetation. On this map, the fire patterns within each ecoregion are uncannily similar.

"Each ecoregion has a combination of natural features that may or may not be susceptible to ignition. By examining fire history from this perspective we can calculate the fire cycle for each of those ecoregions," says Milne. "Depending on the ecoregion, it might be 500 years, or it might be 75 years."

"In the boreal forest 5 percent of fires account for 95 percent of the area burned," Milne says. "A small number of very large fires contribute to the total area burned." Almost 2 million hectares burned in the Yukon through the 1990s, but over 90 percent of it was caused by lightning. In addition to total area burned, Milne's graphs also count the total number of fires. Overall figures show that fire starts are fairly evenly split between lightning and human causes, though this differs greatly between communities.

"Dawson and Watson Lake forests burn primarily because of lightning," explains Milne, "while Whitehorse and Haines Junction forests ignite primarily to human-caused reasons." Ninety percent of fires around Whitehorse are caused by humans, whereas just the opposite is true for the Dawson area. As Milne points out, Whitehorse is not in a high lightning zone, and there are considerably more people.

"We've successfully fought fires around our communities in the past such that now we have an issue with the buildup of fuel around these population centres," says Milne. Any forest vegetation that is available to burn is considered 'fuel' -- this could include live conifers, grasses, dead trees or an accumulation of needles.

He describes the four most common ways that human-caused fires start. "Escaped campfires are a major cause of fires. Forest fires are also started by rural residential homeowners burning backyard debris. You have to be very careful."

"Kids who play with fire or matches are also a major cause of fires, as are industrial activities like land clearing for agriculture or forestry."

If you spot a fire, Milne suggests making a few observations that will help fire management teams respond appropriately. "Most importantly, we ask that people take note of a specific landmark or geographical feature that will help us fix the location of the fire."

"We are also interested in knowing what the fire is doing. What colour is the smoke? Is the smoke going in a particular direction because of wind? If possible, we like an estimate of the size of the fire. Is it the size of a backyard or a football field? It's also important to find out if there are any people or structures around."

Through the FireSmart program, Milne works with property owners who want to assess and mitigate the risk of fire to their property. For information about FireSmart, call 667-3342.