The peak for fall colors in Colorado’s northern mountains probably is being delayed a week to 10 days by recent above normal temperatures, according to an expert with the Colorado State Forest Service.
“My thought is that we’re at least one week behind what we would consider to be an average peak,” said Dan West, the state forest entomologist and a Colorado State University faculty member. “And we haven’t had any storm fronts move through that would start to move some of the pigments within the trees.”
The great fall foliage show typically begins in the northern third of the state and moves south through September and into October. The primary trigger for leaves changing color in the fall is shorter days — we will have nearly an hour and 18 minutes less daylight today than we had one month ago — but once that starts, temperatures and other weather factors have effects on the quality of fall colors and the length of leaf-peeping season.
The ongoing drought in parts of the state also is having an effect on foliage, with the drought in northwest Colorado rated extreme. That means less vibrant colors in those areas, with shorter durations of color.
“A lot of the stands around the Steamboat area suffered quite a bit from drought effects,” West said. “I did some low-level flights over a lot of the aspens in and around Steamboat. I don’t see anything that showed anything other than drought effects on those aspen stands. They look pretty poor in that area. I believe it’s because of the impacts of drought over numerous years. We’re just not seeing stands that are vibrant right now.”
The extreme drought in the northwestern part of the state also is affecting western Grand County and northern Eagle County.
“In the Gunnison Basin as well, there are many aspen stands that have that brownish tint to them,” West said. “That’s because the margins (edges) of the leaves are dying back because of drought conditions.”
Experts have predicted good leaf peeping in the Front Range this year, including higher elevations to the west, because rainfall has been better there.
The onset of cooler weather will speed the onset of fall colors peaks, but the damage in drought areas has been done.
“It seems like it’s been abnormally warm over the last couple of weeks,” West said. “Obviously day length is what triggers the greens to come out of (disappear in) those leaves. What we really want is those cooler evenings to make those yellows and reds really pop. We just haven’t had it. Drought normally would speed things up. And we are definitely seeing browning of some leaves, where they’re just not going to turn, they’re dropping. That is 100% drought related. But from the stands that look like they’ve had enough water, it looks like they’re just a little bit delayed.”
West is hoping the cooler temperatures that are forecast for this week will speed things along.
“That would set the stage for really good conditions (this) week and the week beyond,” West said.
“I want to see days when it’s super sunny and bright during the day, and then it gets super cool in the evening. That’s when you really start to get those reds that pop. We’re just starting to get into that now.”
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