November Snow - November 8th and 9th, 2002
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On November 8, 2002, A powerful upper level jet stream, in excess of 140 knots, moved over Southern Colorado. The system brought with it moist air and freezing temperatures - with temperatures at 700 mb (approximately 10,000 feet above sea level) at 0 to -2C. The snowfall with this system was primarily orographic, or terrain-driven. Many times storms which drop several inches of snow have some help from the upper levels of the atmosphere, which aid in lifting the air, cooling it, and thus generating precipitation. This system had very little in the way of strong 'dynamics' with it in the upper levels. But as strong westerly winds and moist air slammed into the Continental Divide, for a period of approximately 48 hours, great amounts of snow were left behind in locations where temperatures supported freezing precipitation, and terrain favored orographic precipitation.
Hardest hit were the Sawatch Range and adjacent valleys in Central Colorado, and the San Juan Range in Southern Colorado. The La Garita Mountains, which are favorable for snowfall in westerly flow, also likely received heavy snowfall. The Sangre De Cristo Range also received snow, with areas above 10,000 feet seeing over a foot.
In the map above, contours are based on actual snowfall measurements, others are based on the liquid-equivalent of snowfall from SNOTEL data. Snow levels were generally 9000 feet and above.