There's no absolute when explaining a red-hot Whitehorse housing market, other than calling it red-hot.

A popular local theory that comes up most often is a rampant divorce rate.

However, an informal study by a local realtor a year ago suggested just seven per cent of purchases at that time were prompted by separation or marriage.

Mortgage rates remain favourable.

It's been suggested pressure on the supply and demand curve from a shrinking number of available residential lots is pushing prices upward.

As well, Mayor Ernie Bourassa believes that a general shortage of contractors means homebuilders are in the position to charge more.

And then there's the sharp spike over the last year in the Whitehorse population. One economist ties that to the mammoth increase in Yukon government spending in recent years.

Just over a year ago, in the first three months of 2004, the average price for a home in Copper Ridge sold for $191,000.

The average jumped to $214,300 in the first quarter of this year. That represents a $23,300-increase in the average price, according to the most recent numbers published by the Yukon's Bureau of Statistics.

Country residential properties, however, are leading the charge.

Last year, the four rural properties that sold in the first quarter fetched an average price of $189,800. The eight that sold in the first three months of this year went for an average of $246,700, amounting to a $46,900 or a 30-per-cent increase.

Across the board, taking into account sales in all Whitehorse neighbourhoods, the Bureau of Statistics is showing an average increase of $20,000 per sale up from $176,000 in the first quarter of 2004 to $191,100 for the first quarter of 2005.

It's a seller's market.

Not uncommon these days are home buyers willing to pay more than the asking price, and even then, don't have any guarantees of a successful bid.

Whitehorse real estate agent Michael Brine believes the skyrocketing housing prices in the city and on the outskirts go right back to the basics supply and demand.

The statistics bureau is reporting an increase in the Whitehorse population of 600 residents over the last year.

Brine estimates more than 850 have moved into Whitehorse and the surrounding area.

When you add 850 people to the local population, 200 more homes are required, essentially, says Brine.

From what he sees, there's been a noticeable increase in the number of single mothers entering the housing market.

It's also his view that general instability in the world is making countries like Canada and spots like the Yukon in particular a more attractive place to live.

But it all comes right back to supply and demand, says Brine.

Like the recent warning to Whitehorse city council by Mike Racz, the president of the Yukon Real Estate Association, Brine agrees politicians from both the city and the Yukon government must be vigilant in their quest to maintain a healthy inventory of new lots.

The real estate industry suggests a stockpile of 200 lots at any one time is the benchmark to keep the Whitehorse market balanced.

Seldom has the 200-mark been met. But in recent memory, demand has never imposed itself on the marketplace as it's doing now.

As of this morning, there are 16 Copper Ridge lots available over the counter at the territorial lands branch, and one mobile home lot in Arkell.

Another 39 lots in Copper Ridge are expected to be available next month, and 69 more in October. The last 106 lots in the Copper Ridge development are scheduled for sale next fall.

That's it for new urban lots in the city, until city council figures out what it wants to do with the potential for some 20 residential infill lots in Riverdale between Boswell Crescent and Firth Road; the expansion to the Takhini North subdivision, with the potential of 80 new duplex lots; and in the area north of McIntyre Creek behind Yukon College to the west of Mountainview Drive, referred to as the Porter Creek extension.

The recent appetite for urban lots, however, has been ferocious.

When the first 141 Copper Ridge lots were put up for lottery in 1995, there were no applicants.

Over the years, demand was steady 72 Copper Ridge lots sold in 1997; 56 in 1998; 39 in 1999; 34 in 2000; and 50 in 2001.

But in 2002, the curve began bending noticeably upward, with 80 lots sold, followed by the sale of 78 in 2003 and 117 last year.

So far this year, 82 Copper Ridge lots have sold.

Bourassa agrees there is a pressing need to get on with more planning to ensure a stable inventory of new urban lots. The city and the Yukon government as the land developer have been able to meet the demand so far, he says.

And in their defence, the mayor maintains, the crunch is coming on the wave of the unforeseen three-per-cent increase in the city's population that nobody could have predicted.

While the pressure is on, Bourassa is confident the city and Yukon government can expedite the next long-term urban sprawl the lower Porter Creek bench next to the Mountain View Golf Course which has pretty much the same capacity as the multi-year Copper Ridge development.

The mayor points out they're already talking about it. It is possible to advance the development and have the first lots available before 2009, though how much ahead of 2009 is another question, the mayor concedes.

Bourassa says the larger issue comes after the Porter Creek bench development.

If you look at a map recently composed by the city's planning department, there is not a lot of room for large urban residential developments, once you subtract parkland and green space, aboriginal land claim selections and areas not suited because of topography, he says.

In hindsight, says the mayor, the $20-million sewage lagoon system that went on line in 1995 was built in the wrong place, as it has alienated a large tract of land perfectly suitable for urban development.

On the other hand, an analysis of the residential requirements for the city that was updated last year suggests that at some point, the bubble is likely to burst as the impact from the baby boom years begins to fade.