* WHAT...Heavy snow possible. Accumulations are uncertain at this time but may range from 2 to 4 feet above 5000 feet. Locally higher amounts are possible at higher elevations. Winds could gust as high as 45 mph. * WHERE...West Slope Northern Sierra Nevada and Western Plumas County/Lassen Park Counties. * WHEN...From Friday afternoon through Sunday morning. * IMPACTS...Dangerous travel conditions with chain controls and road closures possible. Low visibility due to combination of wind and heavy snow. * ADDITIONAL DETAILS...Snow accumulations remain above pass level through Friday afternoon, then drop to 5000 to 6000 feet late Friday night into Saturday. Potential for mountain snow to continue into early next week.