There’s always a time lag when housing prices seem to defy gravity as people try to hold out as long as they can, simply not accepting that the value of their property has already collapsed.
It took about a year in 2008, between when sales went to virtually nothing (people wouldn’t pay the prices being demanded), until the collapse set in.
There is no real housing market, it’s a derivative of the mortgage market. In these cities there are more people who qualify for recently re-rolled-out special loan programs. Just like 2008, subprime borrowers are being used to prop up markets, and inevitably left holding the bag.