Boulder is one of the snowiest cities in the United States. In a typical winter, about 80 inches (roughly 200 centimeters) fall in the heart of town. The snow is even heavier near the NCAR mesa--often 100 inches or more--because of its higher elevation.

Snowstorms on the Front Range usually occur when cold winds from the east or northeast are forced upward as they reach the foothills, causing the air to cool. Water vapor in the air soon condenses as snow. This effect is strongest between Boulder and the highest mountain peaks to our west.

Heavy snow in Boulder usually melts within a few days, even in midwinter, because of our sunshine and frequent mild spells. However, the crevices and trees on the Flatirons (the rock formations just behind the NCAR mesa) offer shelter from the sun. This can keep snow from melting in some spots until as late as May. Many of the small-scale differences in vegetation on the mesa are due to differences in the timing of snowmelt.