JACKSON, Wyo. \u2014 A strong weather system has brought rain and snow to the valley. Teton Pass is already slick and snow-covered this morning. If you're headed over, be careful as everyone remembers how to drive in the snow. A winter weather advisory is in effect for the NW Wyoming mountains through 6 p.m. Sunday. Heaviest snow is expected today and tonight.\r\n\r\n\r\n\r\nAdditionally, the National Weather Service has issued a flash flood watch today through Sunday morning for Jackson Hole, Star Valley, Upper Green River Basin Foothills, and elevations below 8500 feet in the Salt River and Wyoming Ranges. The greatest hazard will be rock and mudslides in steeply sloped canyons such as Hoback and Snake River canyons, as well as recent wildfire burn scars including the Roosevelt burn scar in Sublette County.