Leaves making fall transformation

As the fall season continues to advance, the beauty of the Inland Northwest is enhanced by the tremendous fall foliage. This weekend and early next week may be the peak when we’ll see the greatest display of color across the region.

During this time of year, the mixture of reds, purples, oranges and especially yellows will dot the landscape. In the spring and summer months, the green leaves actually serve as food factories for the tree’s growth. This food-making process takes place in the leaf, which contains a chemical called chlorophyll. This amazing chemical absorbs energy from sunlight to transform carbon dioxide and water to carbohydrates, like sugars and starch. Chlorophyll also gives the leaf its green color.

In the fall, fewer daylight hours and cooler temperature result in the leaves stopping their food-making process. The chlorophyll breaks down and the leaf’s green color disappears. The other colors of red, orange, and yellow in the leaf now become visible, making for spectacular displays before the leaves eventually fall off the trees.

Sugar maples and birch trees often show the most array of color at this time of year.

The intensity of the colors is affected by the weather as well. A class of pigments, called anthocyanins, are responsible for the bright red color in certain tree leaves. Bright sunshine and dry weather enhance the production of this pigment, so the brightest autumn colors are produced when dry, sunny days are followed by cool, dry nights.

If one is planning some local “leaf-peeping” this fall season, this weekend or early next week is probably the best bet. The recent rains have literally “cleaned-out” the air and it seems that many of the trees are at or near-peak of color. There should be plenty of sunshine with mild daytime temperatures between now and early portion of next week that should make for some great photography.

If you’re looking for ideas on where to go for the most scenic views, the U.S. Forest Service operates a toll-free hotline with weekly updates on fall foliage colors across the nation. The number is (800) 354-4595.

We finally received some much-needed moisture this past week and it looks like we should see more rain between now and Halloween. In fact, the weather for the trick-or-treaters should be cool with the possibility of scattered showers, almost typical for this time of year.

The latest forecast, assuming that El Niño continues to expand, still shows that Spokane, the Spokane Valley and the Coeur d’Alene regions may see near to slightly below normal precipitation between now and the through the first half of this upcoming winter. If El Niño grows at a more rapid pace, the moisture may increase as well. Our driest periods tend to occur during weak El Niños, with wetter conditions during moderate warm-water events. And, it may not be long before this new El Niño reaches such a stage of intensity. Temperatures may also be cooler than average as this area will be under a northwesterly flow from Canada until late December.

After the holiday season, we should start to see storms bring more much-needed moisture to our area. In other words, the second half of the winter season should be warmer and wetter, perhaps cold enough to produce decent snows, particularly in January, in the higher mountains and possibly down here. So far, elevations near 4,000 to 5,000 feet or higher in Eastern Washington and North Idaho have already seen a few inches of the white stuff.