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La Niña and El Niño 

La Niña and El Niño 

A Brief Look into the Weather Patterns of the Pacific Northwest 

By Jessi Vietz 

This spring, residents of the Walla Walla Valley have been experiencing a wide variety of weather. Seventy degrees and sunny to snow and hail in the span of one week, or complete shifts in weather within a single day! These changes can be frustrating when you are freezing in the morning and sweating by lunch. 

If you keep up with the news, it is not uncommon to recognize stories such as “Record Breaking Heat in the East” or “Flooding in the South.” However extreme these trends in weather seem, they actually follow a semi-consistent pattern caused by two opposing climate patterns graciously named “El Niño” and “La Niña.” 

During a normal weather cycle, trade winds bring warm waters from South America west towards Asia. Then, in order to replace those warm waters, cold water rises from the depths of the ocean in a process called “upwelling.” [1] 

El Niño and La Niña break this normalcy, which can have interesting effects on life as we know and understand it. According to the National Oceanic and Atmospheric Administration, “El Niño and La Niña can both have global impacts on weather, wildfires, ecosystems, and economies.” [2] 

Let’s dive into how these weather patterns work. Starting with El Niño, which means “Little Boy” or “Christ Child” in Spanish, with its full and lesser-known name “El Niño de Navidad” due to this occurrence peaking in December. El Niño was first noticed by South American fishermen in the sixteen hundreds who were curious about strange episodes of warmer water in their territories. [3] 

When a season of El Niño is happening, the trade winds are weakened causing warm waters to be pushed back east towards the west coast of the U. S. instead of west. This affects our weather significantly, due to pacific jet stream of warm water being pushed south. “With this shift, areas in the northern U.S. and Canada are dryer and warmer than usual. But in the U.S. Gulf Coast and southeast, these periods are wetter than usual and have increased flooding.” [4] 

Along with the weather, our pacific marine life is greatly impacted. Upwelling, which occurs during normal conditions, is crucial for bringing cold and nutrient dense waters to the surface. This causes species of phytoplankton, the main food source of many fish, to starve or migrate, causing in turn everything that relies on fish for food to dwindle in numbers as well. [5] 

Now let’s talk about El Niño’s counterpart. “La Niña is also sometimes called El Viejo, anti-El Niño, or simply ‘a cold event,’” due to it having the opposite nature of the warm El Niño waters. During La Niña, those same trade winds are increased in strength, pushing an excess of warm waters towards Asia and leaving the west coast of the U.S. with lots of cold upwelling. [6] 

This pushes the pacific jet stream north which “tends to lead to drought in the southern U.S. and heavy rains and flooding in the Pacific Northwest and Canada.” La Niña also causes winters to be warm and docile in the Southern states and even colder in the Northern states, as well as an increase in hurricanes. [7] 

The cold, nutrient-rich waters from upwelling off the Pacific coast create an environment for marine life to thrive. If you enjoy the occasional fishing trip, you should look to El Niño for tropical species such as yellowtail and albacore tuna that enjoy the warm coastal waters. Or thank La Niña for an increase in species such as squid and salmon that thrive in the cold waters. [8] 

See Also

Earth day is arriving April 22 this year, so the next time you curse Washington for being shorts and t-shirt weather on Tuesday and cold and rainy by Friday, take a moment to think about the complexity of our Earth. It truly is incredible for our lives to be sustained and dictated so greatly by two opposing weather systems. 

References 

  1. US Department of Commerce, N. O. and A. A. (2009, March 26). What are El Nino and La Nina? https://oceanservice.noaa.gov/facts/ninonina.html  
  1. Ibid. 
  1. Ibid. 
  1. Ibid. 
  1. Ibid. 
  1. Ibid. 
  1. Ibid. 
  1. Ibid. 

Photo 

“The Northern Lights over Washington State’s Palouse Falls”. Shot by WWU Student, William Frohne. Accessed on 4/14/2022

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