Though it seemed unlikely, Claire Anderson couldn't shake the notion her real-estate broker had taken her to the scene of some terrible crime.

They'd crossed an unkempt yard to enter the rundown Southeast Portland home through a back door. Inside, splotches covered the walls and ceiling. The lights flickered gloomily.

"It was the creepiest horror scene," the 29-year-old said. But "we still walked around and talked about what we could do to make this horror movie house work."

That's because after touring more than a dozen homes and trawling hundreds of others online, she could no longer automatically dismiss a house with an "Enter at your own risk" sign tacked to the front door. Not for her first home, and certainly not one within her price range.

The starter home has become an endangered species in Portland's robust real estate market -- even for middle-income earners with decent savings like Anderson.

Inventory in the ballpark of $300,000 is rapidly disappearing as prices far outpace wages, a scenario exacerbated by the continuing fallout of a homebuilding drought, the region's surging population and the tendency of current homeowners to stay put instead of move up.

And rising interest rates threaten to further erode buying power, leaving first-time home buyers with even fewer options.

More competition, fewer homes

Portland has long held strong appeal for its relatively low cost of living -- a West Coast outpost without Seattle- or San Francisco-level rents, where artists, entrepreneurs and working-class people could build a life and perhaps buy a home.

But homeownership has increasingly become out of reach in the metro area. Data from the real-estate firm Zillow show just 61 percent of today's housing stock is affordable for median-income earners -- around $64,000 today -- compared with 76 percent in 2000.

That would put today's share of affordable homes near levels last seen before the housing bubble collapsed in 2007-2008, and ushered in a wave of foreclosures and the financial crisis.

But today's unaffordability is driven by a shortage of homes, both for sale and for rent. There's also been far less construction of new homes as developers work to bring more rental units online.

Flash sales and bidding wars are no longer anomalies in the metro area, in large part because there simply isn't much to choose from. A mere 3,300 homes were listed at the end of February, according to the Regional Multiple Listing Service, or a six-week supply based on current trends. A more typical market would have a six-month supply.

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Homeowners, seeing little reason to subject themselves to the stress and expense, are loath to re-enter the market

"People are buying their 'starter home' and living there forever," said Alyssa Isenstein Krueger, a broker with Living Room Realty in Portland. "They don't see themselves as being able to make the leap to the next level, so there's less turnover."

As a result, small homes in desirable neighborhoods are seeing prices bid higher. In many cases, first-time buyers are competing with investors, flippers, developers and other cash buyers.

Home sellers usually will opt for the cash offer, which promises certainty that someone in need of a mortgage can't provide. And developers often bid more than the house is worth because the bigger one they plan to replace it with will fetch a much higher price.

As a result, first-time homebuyers are looking farther from the city core to find affordability and less competition.

The Portland Housing Center, a nonprofit that works with first-time homebuyers, has sought to meet that need with new satellite offices in Beaverton and Vancouver.

"For a while the suburbs were the place to go," said Felicia Tripp, the center's deputy director. "But the inventory shortage is Portland metro-wide. It's going to be difficult, even in the suburbs."

Rising mortgage rates

What starter homes are available, however, remain within reach only because of low mortgage rates, which can dramatically affect monthly payments. But mortgage rates have been creeping higher. In March, the Federal Reserve raised its benchmark rate for only the third time since the Great Recession, and most observers expect the central bank to raise rates at least two more times this year.

Should rates rise to 2006 levels -- about 2 percentage points higher than today -- the share of affordable homes would drop to just 41 percent, the Zillow data show. Such a jump could add nearly $300 to the monthly payment on a $300,000 home, and that's without any increase in price.

Most forecasts call for a more modest rate increase over the next two years, but prices are expected to keep growing. The median Portland-area home price jumped 10.4 percent in March, year over year, and has surged nearly 72 percent since 2012, RMLS data show.

Such a dearth of starter homes is something the Portland real-estate market has never seen before, Tripp said.

"We're bracing," she said. "There's always been, generationally, a market for first-time homebuyers. This is new to us."

Anderson, the would-be homeowner, considers herself relatively lucky.

She has a job at a Portland nonprofit that pays well enough, and her rent held steady long enough that she could save up a healthy down payment. Her family can also contribute -- increasingly the norm for first-time homebuyers.

And there's no big rush, such as an expiring lease. But her relatively low rent recently jumped $200 a month, and the prospect of future increases might force her to find a different line of work, or leave Portland.

"It may be that I don't find anything. Then we rent as long as we can, and then," she said, "I don't know."

-- Elliot Njus

enjus@oregonian.com

503-294-5034

@enjus