Although it doesn't change the fact that a distribution made when you were a resident of California is subject to California income tax, this was apparently a distribution from a qualified retirement plan, not an IRA, because no employer has the authority to liquidate an IRA. Only you as the owner of an IRA have the authority to request a distribution from an IRA.
Note that if the distribution actually occurred *before* you changed your residence from Washington to California, this is not California income, although I think it still might slightly affect the tax that you were required to pay to California because of the way part-year California income tax is calculated. Since you said that you both moved to California in January 2013 and received the distribution in January 2013, it's not clear if the distribution occurred before or after you became a California resident. A part-year resident must file a part-year California tax return, Form 540-NR. If you were a resident of Washington when the distribution occurred, there would be no state income tax since Washington does not have a state income tax.
