Fall colors expected to peak in Western Washington in upcoming weeks, but will be duller than normal

Fall has officially begun in Western Washington with the region's first cold front of the season bringing blustery conditions this week. But fans of the colorful season should expect to see less bright fall foliage than usual this year.

Weather experts are predicting that the region's hot, dry summer will lead to an earlier drop in leaves and less vibrant colors this year. Colors are expected to peak near Oct. 18 in Western Washington, according to the 2021 Fall Foliage Prediction Map. Eastern Washington will see a slightly earlier peak, around Oct. 11.

The chemistry behind fall's brilliant hues of orange, yellow and red actually begins in the spring, according to the USDA Forest Service, with enough adequate rainfall to produce healthy trees into the summer months. Leaves change color in the fall as the days grow shorter and production of chlorophyll — then green pigment found in plants — begins to decrease as the plant prepares for dormancy in the winter.

The decrease in chlorophyll allows other compounds, such as carotenoids, anthocyanins and flavonols, to break through. All of the pigments eventually break down and only brown tannins before the leaf falls to the ground.

But without adequate rain in the spring and summer, leaves can change color earlier than usual and sometimes even skip the red, orange and yellow tones and go straight to brown. An abundance of precipitation in the eastern portion of the country over the spring and summer has caused leaves to appear more vibrant this year, leading to excellent viewing opportunities on the opposite coast.

This past summer was one of extremes in Western Washington: not only did the region experience a record-breaking heat wave with temperatures hitting the triple digits, but also a dry streak of 51 days with no measurable precipitation, falling just shy of record breaking.

The heat also caused many leaves to not even make it to the fall season. Scientists noted that leaves prematurely browned and dropped off in a condition called "foliage scorch" during the extreme heat event. But that doesn't mean that all hope for fall colors is lost.

"The colors across the Cascades should be good," noted AccuWeather Forecaster Paul Pastelok.

Specific native trees have also experienced impacts. A recent study from the University of Washington and Washington Department of Natural Resources (DNR) found that bigleaf maple trees have seen increased die-offs in the last decade years due to hotter, drier summers. Researchers found that intense heat conditions and less precipitation not only caused the tree to grow less, but also weakened the tree's immune system and made it more susceptible to disease.

"These results show that summer heat and drought impact the health of iconic tree species of Washington, like bigleaf maple, even in Western Washington, a region known for abundant precipitation," said co-author Amy Ramsey, an environmental planner and forest pathologist in a news release. "Health impacts to our forests and tree species are likely to continue as we have increased periods of drought each year."

The summer's extreme heat also had an impact on the region's snow packs. June's unprecedented heat wave melted 30% of Mount Rainier’s snow pack according to the Northwest Avalanche Center, giving the mountain a bare, rocky appearance over the Emerald City for much of the summer.

Luckily for hopeful leaf viewers, the state's wildfire season has been winding down the last few weeks. As of Friday, there is only one large wildfire burning in the state, according to the Northwest Interagency Coordination Center. The fire at Schneider Springs is currently 91% contained.