Federal banking regulators continued to raise warnings about the rapidly growing “nontraditional” mortgage market, citing new volume data from bank surveys and offering consumers sobering advice about new species of home loans. The Federal Reserve Board’s latest periodic survey of senior loan officers found that over half of the banks have been originating an increasing volume of alternative mortgages during the past year. The Fed defined nontraditional mortgages to include option ARMs, interest-only loans and…