SOUTH LAKE TAHOE, Calif. – The National Weather Service in Reno has issued a new Winter Weather Advisory for Monday at 4:00 p.m. to Tuesday morning at 4:00 a.m. This new advisory is due to what is known as “lake effect snow.” Six more inches of snow can drop on the south shore of Lake Tahoe area this evening.

Lake effect occurs when a mass of unstable cold air moves over a mass of water that is warm in comparison. The lake provides moisture for the band of weather moving over it.