Chinook And Föehn Winds: What They Are And How They Are Formed

Chinook And Foehn Winds heading

The names may sound foreign, but Chinook and Föehn winds are actually quite common occurrences. They are created throughout the world and are both caused by the same process.

If you live in an area which commonly experiences these winds, some of you may be familiar with the names, but do you know how they are formed in the first place?

Chinook winds got their name from the Chinook Native American people who lived in coastal areas near the Columbia River (in the States of Washington and Oregon), where these winds occur on a regular basis. 

Föehn winds originate from the German word "Föhn", which literally means hot, dry wind. It is in this region of the Alps in Central Europe where this occurrence was first studied.

Although these winds have unique names, depending on the region where they occur, they are the same phenomena, no matter where they form in the world.

What Are Chinook And Föehn Winds?

The first thing to know about Chinook and Föehn winds is to understand that they are essentially the same type of wind. You may not be aware of it but the area you live in, or one nearby, may be experiencing these air movements regularly on a seasonal basis. 

By providing a quick summary of what Chinook winds are, and then giving a more detailed description of the Föehn winds they are based upon, you will be able to get a clear understanding of what these type of winds are an how they are created.

What Are Chinook Winds?

Chinook Wind

Chinook winds are Föehn winds that form when moist air from the Pacific Oceans rises up against the Western Rocky Mountains, cools down and cause precipitation. The cool dry air now starts to descend down the easterly slopes of the Rockies.

Gravity causes the air to accelerate down the mountain slopes and heat up. As it descends, the air mass is also compressed which leads to adiabatic warming, further heating up the air. This results in the warm Chinook winds experienced in American Northwestern interior.

Defining Föehn Winds And How They Are Formed

As already mentioned in the introduction, Föhn (Föehn) winds were first identified and studied in the Alps of Central Europe.

The name "Chinook" simply refers to the Native Americans who lived in the region where this phenomenon frequently occurs, but are essentially nothing more than Föehn winds.

The process through which a Föehn wind develops follows the same steps, no matter where they are found throughout the world:

Foehn Winds

As moist, warm air blows and reaches the windward side of a mountain, it starts to ascend against the mountain slopes. As it gains altitude, the air also starts to cool down.

Once the air reaches a height where the air has cooled down enough for condensation to take place, precipitation in the form of rain and snow follows. In the process, the air loses most of its moisture, while the condensation also allows for the release of latent heat.

(As contradictory as it may sound, condensation is known as a warming process, and evaporation as a cooling process. To make more sense of these seemingly opposing statements, you can find detailed a more detailed explanation in this article.)

As the air reaches the mountain top, it is now both dry as a result of the precipitation, and slightly warmer due to the release of latent heat during the condensation process.  

It now starts it descend down the leeward side of the mountain. As the air continues to move downward, the effects of gravity force it to speeds up and become warmer as it continues to accelerate down the slopes towards the bottom of the mountain.

The mass of descending air also has a substantial effect on the heating process. As a large volume of air descends it causes the air to compress, a process called adiabatic warming. The descending masses of air causes so much pressure that it results in the air to heat up.  

All these steps and processes combined results in a warm, dry wind of considerable strength know as Chinooks, Föhns  

Regions situated on the leeward side of a mountain experiencing this phenomenon, usually experience experience warmer and more pleasant weather conditions in a cloudless sky.

Effects of A Chinook And Föehn Winds

The warm and pleasant weather experienced by areas in Central Europe parts of Northwest America as a result of these winds, is not the only effect they have on the environment.   

1) Melting And Evaporation Of Ice

The warm and dry nature of these winds resulted in the name "ice-eaters", due to their ability to melt and even evaporate ice before it can melt. A strong Föehn wind is able to make a layer of 30 centimeters (12 inches) of snow to "vanish" within a day.  

2) Loss Of Ground Water

The intensity of some Chinook wind occurrences can lead to exposed soil to lose a big percentage of its moisture. It has been reported that wind gusts from a Chinook wind can exceed speeds of 120 km/h (75 mph). This can have a widespread negative effect.

Ingeniousness vegetation naturally will suffer as a result, but it has an even larger impact on the agricultural sector, where crop losses can impact the local economy

3) Effects On general Health

Several debates are ongoing around the real health effects of Chinook/Föehn winds. It seems the most significant discussion revolves around the issue of whether these winds have a real health impact, or just perceived as such by people who are "affected".

However, there is consensus over a few widely accepted health effects. This applies to both the positive and negative impacts of Föehn winds.

exhaustion

On the positive side, the people whose lives are severely inhibited by freezing conditions, find their lives easier to manage, as their daily activities are made easier and their bodies are able to cope much better under the warmer conditions.

A general feeling of well-being has also been documented, but it's unclear whether it is a result of the relief mentioned in the previous paragraph, or if the warmer weather and clear skies directly trigger these emotions.

(The clear skies allow sunlight through which helps to generate vitamin D in the body which is responsible for the release of endorphins.)

On the negative side, Föehn winds are connected to the migraines many people are experiencing during the occurrence of this phenomenon. So much so, that these migraines are often referred to as Chinook headaches.   

Less serious and related effects have also been documented, but many of these have not been substantiated or enough research done.    

Conclusion

After reading this article, the "shroud of mystery" should have been lifted over the foreign sounding Chinook and Föehn winds.

These winds also have many other names, mostly related to the region where they occur. In South Africa, they are commonly known as a Bergwind, in California the Santa Ana, in Argentina the Zonda winds, and in Slovenia the Fen. 

The examples mentioned in the previous paragraph are just a few examples of a magnitude of local names for the same phenomenon. 

So rest assured, the Chinook or Föehn winds you experienced first hand or just heard about, are just local names given to a normal phenomenon experienced throughout the world. 

Feel free to leave me any comments, questions or suggestions, and I will get back to you as soon as possible.

Remember to join my  Mailing List  to be informed whenever a new article is released, and share new developments and helpful hints & tips.

Until next time, keep your eye on the weather!

Wessel


Wessel Wessels
 

Lifelong weather enthusiast. Interest in all things weather-related, and how global climate and local weather interact. Home weather station owner for almost 2 decades, but still learning and expanding my knowledge every day. Keen on sharing my knowledge and get more people involved and interest in both their local weather and how it interacts with climate on a global scale. Love sharing my knowledge on home weather stations, how they work and the many ways you can use them to your advantage. All in all, just a bit of weather nerd.

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What Is The Weather Like In A Coastal Region & Why A Moderate Climate - June 20, 2019

[…] This scenario often leads to areas with high rainfall on the windward side, and dry, warm weather on the leeway side of a mountain near the coast. The Chinook Winds in North America are a perfect example of this phenomenon. It is perfectly explained in this article. […]

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