Lightning sensors thwart forest fire flare-ups

On Aug. 18, lightning struck a heavily wooded area near the Ontario-Manitoba border, sparking a blaze dangerously close to some cottages on Lake of the Woods.

The moment it happened,the bolt's locationshowed up as a bright mark on a computerized map,warning fire officialsat the Ontario Ministry of Natural Resources that conditions were ripe to nurture and grow a dangerous inferno.

"They knew that that was a critical areatheyd had only a little bit of rain on very dry forest fuels," said Mick Rice, weather systems co-ordinator for the ministrys aviation, forest fire and emergency services.

Over the next couple of days, aerial patrols were sent out to within 20 kilometres of the lightning strikeand, sure enough, theyspotteda telltale column of white smokespiraling up from the trees. It wasa small blaze, just 0.1 hectares in size, but too close to the cottages for comfort.

By the time the fire had grownto 0.4 hectares, crews were on the scene and quickly extinguished it, keeping the cottages safe.

2011 a bad year

Lightning starts about a third of all fires in the province, and this has been a particularly bad year for lightning-caused fires compared to those caused by humans,Rice said.

As of Aug. 29, 1,000 fires had burned 628,859 hectares of Ontario forestgreater than the area of Prince Edward Island and nearly 10 times the average of 68,108, for this time of year, over the past 10 years.

And even though the fire season tends to wind down in the fall, it's not yet over. In fact, Environment Canada is predicting awarmer-than-average fallacrossmuch of the country and drier-than-average conditions in some areas.

In areas where thereare homes and communities,fire crewsare deployedquicklytostamp outfires when they are small, to minimize their damage and the destruction of property and infrastructure such as power lines.

Unlike Alberta, which has forestry towers to keep an eye out for wildfires, Ontario relies on aerial patrols to cover its vast expanses of boreal forest.

Knowing where fires are likely to have started makes it possible to send patrols to the right place at the right time. Thats where the provinces 30-year-old lightning detection network plays a key role.

Fifteen detectors, which areregularly upgraded and replaced, are spread across the province, mainly toward the southern end of the northern boreal forest, where more humans live.

When lightning strikes, it generates a radio-frequency electromagnetic radiation that is detected by multiple sensors as far as 1,000 kilometres away.

The sensors have magnets that can tellwhich direction the pulse came from and they are networked so that a computer can compare the time each one detected the strike.

Closer sensors will detect the signal slightly earlier than one that is further away. Using this information, the lightning can be pinpointed within 100 metres in much of Ontarios boreal forest.

This pastJuly, the peak month for lightning, the networkdetected over 177,000 lightning strikes, significantly above the average of 130,000 for that month.

The information is fed into a computer model, frequently tweaked and improved, that overlays the lightning strikes with data about conditions that could increase the likelihood of a forest fire.That tells fire crews where to send theaerial patrols.

However, for all the systems sophistication, the information it providesisn't enough tokeep all communitiessafefrom the natural fires that ravage the boreal forest each summer.

In July, for example,3,500 people were forced to flee First Nation communities in northwestern Ontario as smoke and flames threatened to engulf them.

Rice said a main reason the fires were so bad this year inthat regionwas becausesome hadinitially broken out further north, andhad beenallowed to burn.

"We had a lot of lightning east of the Manitoba elbow, where there werent too many communites, so we sort of let them go for a bit, and it stayed dry and it stayed dry and they started getting bigger and they started spreading," he said.

Eventually, the wildfiresbegan roaring dangerously close to human settlements, forcing fire crews toface thegrowing flameson the fronts nearest the communities.

"By the time theyre actually tackling them,"Rice said, "they have some major fires on their hands."

When deciding when and how hard to fight a forest fire, he added, officialsconsider both the threat against communties and the fact that lightning-caused fires have been part ofnaturesince long before humans existed. In fact, they play a key role in forest ecosystems and some plants rely onfires to propagate.

"Its always a balancing act," Rice said. "If you put every single fire out that erupts, then youre not really doing nature a favour."