Contour Lines: Contour lines are used to determine elevations and are lines on a map that are produced from connecting points of equal elevation (elevation refers to height in feet, or meters, above sea level). profile may be constructed quickly and accurately across any straight line on a map by following this procedure: a. Lay a strip of paper along a line across the area where the profile is to be constructed. b. Mark on the paper the exact place where each contour, stream and hill top crosses the profile line.
During may you will find snow at the North and South pole. It will also snow in high lying areas such as some mountains. Many people forget that while in May that while the Northern Hemisphere is experiencing spring (which in some places means there is still snow), the Southern Hemisphere is experiencing winter.
The first snowfall of autumn for South Lake Tahoe arrives as early as September or as late as November. The season's last snowfall typically happens in June, although about one in four years gets no new snow after May. The resort city is normally free of snow every year during July and August.