Colorado's Drought Could Accelerate -- And Dull -- Fall Colors This Year

DENVER (CBS4) - Flocking to the high country to view the spectacular fall foliage is an annual tradition for many families in Colorado. Prolonged drought could slightly change when to take your trip and the brilliance of the color you find when you arrive.

The annual fall color change is triggered by increasingly shorter duration of daylight along with cooler temperatures. These differences cause the chemical composition of leaves to change. The green, which is called chlorophyll, fades away leaving yellow and orange that is masked by the green in spring and summer to become visible before the leaves drop. The result is the splendor seen across every mountain range with aspen trees in Colorado.

Because the color change is driven primarily by daylight, the colors are guaranteed change regardless of other factors like drought. But according to Forest Entomologist Dr. Dan West at the Colorado State Forest Service, "the drought could cause colors to peak days earlier than usual and the intensity of the color may be diluted compared to years when precipitation is adequate". "This is because dry conditions stress aspen stands", says West.

As of August 27, more than 90% of Colorado is experiencing at least severe drought including the entire Denver metro area. And about 35% of the state is experiencing extreme drought including many mountain areas.

So no major changes are needed to the calendar for when the leaves will be at their peak starting in the northern mountains in mid-September and ending in the southern mountains in mid-October. But it may be best to visit a specific area at the start of the peak window instead of the end. For example, the peak colors for the I-70 mountain corridor from Georgetown to Avon generally happens between September 18 and September 29 each year. So if you plan to visit on a weekend, the weekend of September 19-20 will likely have more brilliant color compared to the weekend of September 26-27 in this area.

And speaking of brilliance, Dr. West says the drought may "dilute the show" but the weather over the next month will mainly dictate how stunning the color becomes this year. "We need sunny days accompanied by cool nights to bring out the most vibrant reds. Sunny days also help burn off the green so we're left with more yellows and oranges", says West. "Strong winds or freeze events reduce the show, so bring on those sunny fall days!", he added.

In terms of the best region to visit this year, West generally says the northern half of the state should be better compared to the southern half. "If I were comparing or thinking about heading north versus south, this season I'd look north, but fire closures may make this more difficult if you're heading west from the northern Front Range" he said.