Predicting the quality or timing of peak fall colors in southeastern Colorado may be more difficult than forecasting the weather for the coming weeks. However, based on the general science of leaf chemistry, and the recent observed and forecasted weather conditions, one can arrive at a general assessment of fall foliage prospects for our region.
Fall colors in southeast Colorado (and all of Colorado for that matter) are most commonly associated with the aspen trees that grow in great abundance at elevations between 6,000 and 11,000 feet. The primary factor contributing to changing leaf colors is the decreasing length of daylight, with progressively longer and cooler nights as we head into the Autumn months. As daylight decreases, the trees conserve energy and the process of photosynthesis shuts down in the leaf. Photosynthesis is regulated by the green pigment chlorophyll, and so as the amount of chlorophyll fades, the other pigments in the leaf are unmasked. One such group of pigments, the carotenoids, gives the aspen leaf its characteristic yellow color.
The consensus of scientists is that the health of the forest, climate, and weather conditions can affect the quality of fall colors. Slightly dry conditions in the late summer and early fall can have a positive effect, since the lack of water to the leaf is one factor triggering the relevant chemical changes in the leaf. A lack of storms or rain can also ensure that healthy leaves stay on the tree, as opposed to being blown off by strong winds. Rain may also aggravate fungal infections that affect the health of the leaves. In general, mild sunny days and cool dry nights without freezing weather are the conditions most conducive to strong fall colors.
The Central Rockies have in general had a warm Summer with average precipitation. Although the Spring was drier than normal, Winter snowpack was adequate, and contributed to a healthy population of aspen with adequate leaf volume. The peak for fall colors in Colorado is generally during the last week of September and first week of October, but varies with latitude, elevation, and location. Without strong storms or winds, peak colors can sometimes last well into October. The Climate Prediction Center is currently predicting a week of slightly above average temperatures, and below normal precipitation in the days leading up to the peak weeks. This forecast should be conducive to an above average display of fall colors. Be sure to get out and enjoy this fabulous display of nature in Colorado!