What's Causing California's Wet Winter?
California is going through one of its most impressive seasons of moisture fall in the last six months. This winter termed a "wet winter" shows increased volumes of snowfall happening throughout the state. The LA Times has reported that snow in the Sierra Nevada has more than doubled over the last month, coming in at around 43.5 inches of water with other regions reporting less impressive, but still massive numbers of equivalent rainfall. While this is uncharacteristic weather for California, it is the result of something that isn't completely unheard of a phenomenon to the area - an atmospheric river storm.
What are Atmospheric River Storms?
Just like a regular river, an atmospheric river, according to the National Oceanic and Atmospheric Administration (NOAA), is a band of water vapor that comes from the tropics, which then cools, condenses and brings rain or snow, depending on the temperature of the environment. California is no stranger to these atmospheric rivers since, on an average year, the state is expected to face between two to three of these. It is such a well-known phenomenon that the expectation of these atmospheric river storms is the premise on which water usage within the state is based. However, there are times when these storms do not show up, and at that point, California risks falling into drought. In the most recent years, the incidence of these droughts as well as their intensity has been relatively high. Science News reports that the drought in 2014 was the worst to date since Charlemagne ruled the Holy Roman Empire.
Weather in the Golden State
California's weather is marked by periods of dryness interspersed by periods of rainfall. Climate Signals notes that atmospheric river storms can account for as much as one-half of the precipitation for the entire state over the course of a single weekend. The intensity of this influx of moisture could have devastating effects on the local areas with disasters like flooding and structural damage being prevalent. California's propensity to suffer from massive forest fires only exacerbates the problem, turning formerly forested areas into potential landslides which could lead to the destruction of property as well as loss of life, as we can see on this blog post by Strom & Associates, which deals with the collapse of a trench. While most of the time, California's weather is benign and even pleasant, when these storms hit, it could be disastrous for some neighborhoods. But that isn't the worst part of the problem.
The Folly of Wasting Incoming Precipitation
It would make sense to think that California would collect the influx of water from these massive storms and store them for when water within the state inevitably runs out during one of their infamous droughts. Sadly, the reality of the situation is completely different. According to Earth Magazine, California primarily depends upon underground aquifers in order to supplement its water provisions during drought periods, but those aquifers have been heavily overdrawn. Combine with that the fact that a lot of the water from the atmospheric rivers being left as runoff instead of being collected and we can see how this births a problem later down the road once the atmospheric rivers stop coming with the same frequency.
Water Management and the Future
California's outlook when it comes to avoiding droughts may be changing. The Water Education Foundation reported that Los Angeles DWP had designed a plan in order to reduce the runoff from these massive atmospheric river-fueled events. While a step in the right direction, this sort of initiative needs to be implemented state-wide in order to bring about change. Using the water from these massive rainfall events can help the state stay ready for the inevitable day when the demand for water outstrips the supply and the atmospheric river isn't there to help the situation out.