When San Francisco public schools open two weeks from Monday, will there be enough teachers for our students? KRON 4 is asking, prompted by the news that there are 51 open positions even at this late date. The shortage has even led Superintendent Richard Carranza to send out an email to staffers enlisting their help in recruiting potential candidates.

One cause for concern, though, might mean that the candidate pool is shallower than ever before. There's been a 53 percent drop in the number of people exiting credentialing programs over the last five years, a district spokeswoman said.

The difficulty of affording San Francisco is of greater or equal concern. Head of the San Francisco teachers union Lita Blan tells KTVU that "Among young teachers it's their number one concern. I hear it all the time. I can't stay in the district if I can't find a place to live."

As Curbed reported last year San Francisco's median teacher salary in 2012 was $59,700. According to data from Redfin, an home affordable for such a person would cost about $220,000.

Of course, there were no such listings in the city then, and there aren't any more now. In fact, 83 percent of California homes were unaffordable on a teachers salary, Redfin claimed.

That email from Superintendent Carranza led to just 60 new applications. But the school district claims to be confident it will fill all necessary positions by the time students fill the halls on August 17.