2:30 p.m. MT | Mount Evans Wilderness, Colorado – The clouds crawl across the sky like slow-moving spaceships. The breeze puffs down from the mountains and shakes the leaves on the trees, sending them down to the forest floor. The sun is shining as bright as it did all summer, but there’s a major difference in its intensity today, its warmth very much welcome now that the air has turned crisp. I can hear the sounds of fall under my boot, the dry, brittle leaves crunching like potato chips. We don’t have the rainbow of colors or the slow, unfolding fall you’ll find in places like Upstate New York. A majority of the trees in Colorado stay green all year. But what we do have here is the white-trunked aspens that go from green to florescent yellow in the blink of an eye each September. It’s a small window — a fine line between summer and winter.