Remember that there was a similar rise in average price over the 2009-10 homeowner tax credit. The rise was far in excess of the average credit of $8000 and popped even before the credit expired for good. Markets behave strangely and not always rationally.
Also keep in mind that foreclosures and short sales are essentially stayed in CA right now due to the Homeowners’ Bill of Rights. Same thing happened in NJ due to a Superior Court case, and the foreclosures are coming on line right now, 2 years late. This isn’t causing a huge dip in prices, but they ain’t goin’ up more than the average rise for spring either.