More than half the homes on the market in seven major American metros are unaffordable, raising the threat of a price bubble in those markets, according to a new Zillow analysis of home price data from across the country. Most of those at-risk markets are not surprisingly on the West Coast, including Los Angeles, San Francisco and San Jose.

No risk of a price bubble anytime soon here in the Twin Cities metro, where 31.8 percent of the houses on the market are unaffordable and 13.6 percent of their income is spent on their mortgage.

Nationwide, one-third of the houses on the market are unaffordable to the people who live in those cities based on the median area income.

The takeaway from the report is that as mortgage rates and home prices rise, affordability will wane, forcing families in those most-expensive markets to forgo buying or move far from the urban core where prices have become the most expensive. And Zillow says that if mortgage rates hit 5 percent, homeownes in the Twin Cities will spend 15.1 percent of their income on their mortgage.