Referred to locally as the "dumpcano" — a combination of dump and volcano — the fire has been burning since May 20 and there's no end in sight, said Iqaluit fire chief Luc Grandmaison.
"What we're facing is a huge mountain of garbage," he said. "We're letting the fire burn itself out."
The chief said the temperature has been measured at 1,400 C.
"That's on the outside surface — can you imagine the heat that's inside that pile?"
As winds continued to blow from the west Friday, about 200 students from two schools were sent home for the second day in a row.
"The principals came to school (Thursday) and the smell was already in the school," said superintendent Paul Mooney.
"The decision was made that, to some degree, the schools were concentrating the smell and things would be better in dispersed homes."
The smell was curling nostrils all over town. Nunavut's health department issued a warning, saying people with heart and lung disease, the elderly and the very young should stay inside.
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The fire is centred somewhere deep within the vast pile of trash that is the Iqaluit city dump. The burning section is a smoky cauldron about the size of a football field and up to four storeys deep, said Grandmaison.
The heart of the blaze is too deep for firehoses to quench it. The pile of garbage is too unstable to attack it with backhoes or other equipment.
"With backhoes, (the pile) has a chance to crumble down and burn the operators," said Grandmaison. "It's too a big a risk. What are we trying to save here?"
The best he and his crews can do is cut trenches through the garbage and isolate the burning section from the rest of the dump. Meanwhile, the smoky, subterranean inferno continues to chew its way through untold numbers of bags of household garbage.
"Kitchen waste, organic waste, cardboard boxes, wood products, any type of garbage you would find in any municipality," Grandmaison said. "Everything is in there."
Tires, metals and paint are in a separate part of the dump.
Mooney acknowledges that more school closures could come, although turning air intakes on and off depending on wind direction could mitigate the problem.
"We're quite used to dealing with snowstorms and bad weather, so we can make decisions quickly," he said.
It's the dump's fourth fire since mid-December. Grandmaison believes the fires come from spontaneous combustion as gases generated by rotting waste ignite in the building subsurface heat.
In 2010, there was fire at the dump that took six weeks to put out.
Inadequate municipal infrastructure is an old story in Nunavut.
As long ago as 2001, Nunavut mayors were pleading with the federal government for extra money to deal with dangerous dumps and failing sewage lagoons. A 2004 report by the Conference Board of Canada made similar points, as did a consultant's study for Environment Canada done in 2010.
The Nunavut government is currently studying Arctic wastewater systems with Dalhousie University.
A 2011 estimate put the cost of modernizing all 25 municipal dumps in Nunavut at between $320 and $500 million.
— By Bob Weber in Edmonton.