Here in the Wenatchee Valley, we live in such a dynamic environment. We are blessed with the Cascade Mountains, lush forests and multiple riverine systems. As we move into the winter months, precipitation will start to turn from rain into snow.
Mountain snow is essential to the dynamics of the environment we all live in. Not only does it provide winter recreation, it brings us fresh drinking water, supplies essential irrigation for agriculture and supports a unique diversity of wildlife and plants.
When snow accumulates in the mountains, we call it a snowpack. Snowpack can differ in elevation as well as the season based on weather patterns. The Wenatchee and Entiat basins receive an average of 15 inches to 60 inches of snow, depending on the elevation and location. As the snow melts, the water starts to travel downhill through valleys and eventually to a stream. The longer it takes the snowpack to melt (as long as middle of June or July), the more water we have available for the summer and fall.
Prolonged snow melt keeps water temperatures in the river cooler for longer. This is what we can see aboveground, but below the soil there’s also an extensive network of groundwater and aquifers that get infiltrated from snow melt. Depending on the geology and soil, the location of subsurface water can be as little as a few inches, to hundreds of feet down below the ground. Ground water is important to a whole host of plant communities, as well as our drinking water when we tap a well into the ground.
Our weather patterns have fluctuated very drastically in recent years. In the mere 5 years I have lived here, I have noticed a longer warm trend in the summers and limited snowfalls in the winter.
The worst snowfall — as in least amount of snow — on record was in 2015. That drought had a cascading effect throughout our valley and the eastern Cascade Mountain region. Through some creative engineering, the effects were not as bad as it could have been. The salmon population took a drastic hit, with high water temperatures and severely below-normal stream flows. Some irrigation districts had to start controlling water use based on senior or junior water rights. This drought also led to the largest wildfire season on record for Washington state. If there was a good snowpack, some of these issues would not have been as severe as they were.
Climate models for the middle of the 21st century has our region switching from a snow dominant to a rain-driven water source. This basically means our climate will look similar to the west side of the Cascade Mountains, where the temperatures will be warm enough to not have snow in the winter but instead rain. The rain-dominant pattern will cause river systems to become “flashy,” instead of having a prolonged period of higher flows during the spring and fall, with very low flows during the summer and winter.
As an outlook for this winter, it’s likely we’ll see La Niña like conditions. What does this mean exactly? Short answer is, similar to last winter. Longer answer is the ocean conditions that help forecast weather for the upcoming months indicate that the weather patterns have a chance of being a La Niña type weather for the winter (NOAA Weather Service, Climate Prediction Center). In layman’s terms, there’s between a 65 percent and 75 percent chance of it being a cold, wet winter. And if last year was any indicator, we should get a normal to above-normal snowpack.
As for your garden, we might have a good cold spell again so be mindful of that. Otherwise have a great winter!
A WSU Master Gardeners of Chelan County column appears weekly in the At Home section. Ken Muir is one of four columnists featured.