Dolores Valley bursts into autumn

The annual fall color display along Colorado Highway 145 to Lizard Pass and beyond will again amaze locals and surely cause tourists to stop their RVs in the driving lane to marvel at nature's brilliance.

The annual tradition gives tourism a boost as well.

"We're seeing the leaf peepers coming through town," said Stuart Hanold, director of the Dolores Chamber of Commerce. "It's a nice time to take a scenic drive."

Annie Belaska, of High Ground Coffee Shack in Rico, reports peak conditions for fall colors.

"This is the week to come on up. It is really beautiful right now with the sun shining brightly making the green, yellow and orange really vivid," she said. "It is really going off up here, so stop in for a latte and snack, and enjoy the drive to the pass."

The Ryman Creek Trail is especially nice right now for fall colors. Also, the Priest Gulch Trail meanders through shimmering aspen forests creating a luminescent, colorful aura seen only in fall.

The more technical aspects are explained by Forest Service scientists. Color changes are primarily regulated by the calender as nights become longer, triggering biochemical processes in the leaf. Carotenoids produce yellow, orange, and brown colors, while chlorophyll gives leaves a basic green color.

The amount and brilliance of the colors that develop in any particular autumn season are related to weather conditions that occur before and during the time the chlorophyll in the leaves is dwindling. Temperature and moisture are the main influences.

A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf, but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions - lots of sugar and light - spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson. Because carotenoids are always present in leaves, the yellow and gold colors remain fairly constant from year to year.

The amount of moisture in the soil also affects autumn colors. Like the weather, soil moisture varies greatly from year to year. The countless combinations of these two highly variable factors assure that no two autumns can be exactly alike. A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most brilliant autumn colors.

But it can all be ruined with one storm.

"Get up here before the high winds hit," Belaska said. "I've seen it happen. One wind storm and its all gone."

jmimiaga@cortezjournal.com