* WHAT...Snow expected above 3000 feet. Additional snow accumulations between 6 to 11 inches, except 12 to 20 inches above 4500 feet. Winds gusting as high as 40 mph. * WHERE...In Oregon, North Oregon Cascades. In Washington, South Washington Cascades. * WHEN...Until 5 PM PDT Thursday. * IMPACTS...Roads, and especially bridges and overpasses, will likely become slick and hazardous. * ADDITIONAL DETAILS...There is a 40-60% chance for snowfall rates exceeding 1 inch per hour along highway 26 near Government Camp, with the highest chances occurring between 12-7 PM Wednesday and between 3-6 AM Thursday..