The number of Californians entering foreclosure slid dramatically in the second quarter to a three-year low as the fallout from the worst of the housing crisis continued to abate. Default notices, the first stage of the foreclosure process initiated by banks on troubled homeowners, plummeted 43.8% in the second quarter over the same period last year to 70,051, and 13.6% from the first three months of the year, research firm MDA DataQuick of San Diego said Wednesday.