What Are Gale Force Winds And How Are They Formed?
We have all experienced those strong consistent winds that make just staying on our feet a battle, nevermind trying to walk. And all of this sometimes happening without a cloud in the sky. We take a close look at these gale force winds.
Strong gusty winds are not uncommon at all and can be found in many major storm systems like hurricanes, thunderstorms and tornadoes. Gale-force winds are not limited to just major storm system though.
The strong consistent gale-force winds we are discussing in this article, are the prolonged gale force winds with gusts that feels like it can literally blow you over. These winds can sometimes occur without any apparent presence of a strong weather system and can last a whole day long.
We need to investigate further and find out what exactly these gale force winds are and what is causing them in the first place.
Let's first establish a technical definition to establish what exactly a gale force wind is:
A gale force wind can be defined as a sustained strong wind, registering between 7-10 on the Beaufort Scale, which indicates wind speeds of 50 - 102 km/h (32 - 63 mph). In short, these strong winds are caused by a rapid drop in air-pressure from high to low. (Air always moves from an area of high-pressure to low-pressure.)
As is the case with most other weather phenomena, things are not as simple as the definition above may suggests. There are actually a number of different factors and weather systems that can form gale force winds in a variety of ways...
What Are The Cause Of Gale Force Winds
As already briefly explained, wind is the result of air flowing from and area of high pressure to low pressure. This is the reason why there are almost always winds of varying strength present around a low-pressure system. You can find out more about the inner workings of both low and high pressure system in this article.
Tropical storms, cyclones and hurricanes illustrate this point very clearly. Depending on the strength of the low-pressure system, winds of gale-force strength are reached very quickly, and can quickly build up to reach hurricane strength wind speeds.
Gale force winds are not just formed as a result of storm systems though. Sometimes, on a seemingly otherwise clear day and pleasant day, you can suddenly be hit by winds quickly building up to gale force speeds.
Anyone living at the coast, specifically in areas where the coastline's relief plays a part, may be very familiar with these winds. Simply put, a gale force wind in these areas can sometimes be seen as a "sea breeze on steroids". Let me explain...
During summer months, both the surface of the ocean and land are heated up by the sun. The land heats up much more quickly than the ocean. During the afternoon, the land also cools down much quicker than the ocean.
A low-pressure system over land is created as a result. The warm air over the ocean flows towards the low-pressure system over land, and it is this air movement that is commonly referred to as a sea breeze.
In specific areas and under certain conditions, this sea breeze can sometimes turn into a gale force winds Cape Town, South Africa for example, is notorious for its strong gale force winds often experienced during summer months.
These gale force winds at coastal regions are formed as a result of mainly 2 factors:
- Occasionally, the difference between the low-pressure and high-pressure air over land and sea is so big, that the breeze can quickly into a strong wind.
- Cape Town's mountainous relief is responsible for amplifying the strength of these strong winds through a funnel effect. (The wind are being channelled through a narrow low-lying area, substantially strengthening it and increasing wind speeds.)
This results in gale-force strength winds in certain areas among the Cape Peninsula. It is not that uncommon for winds to reach speeds of 120 km/h (75 mph).
Cape Town is just one example of this phenomenon that takes place at coastal regions all over the world. San Francisco is also famous for its strong gale-force winds during the summer months.
Here also, a combination of relief and the big contrast in ocean & land temperatures is also responsible for these strong winds. Especially in the San Francisco Bay Area, wind funnel through at the Golden Gate, reaching gale force speeds with gusts of up to 64 km/h (40 mph).
The word, gale in the context of wind definition, normally refers to a full-strength gale force wind. This means wind speeds of 63 - 87 km/h (39 - 54 mph).
Naturally, winds of this wind speeds can be very dangerous and destructive. As a result, whenever a gale is predicted, it is normal for weather forecasters to issue gale warnings.
Interestingly, using the word gale to describe these strong winds is actually a very appropriate word choice if you look at the origins of the word...
The word gale stems from the Old Norse word galinn, which literally means "frantic", "mad" or "tiresome". I don't think anyone who experience gales (or full-strength gale-force winds) on a regular basis, will disagree with this description in any way at all.
As you would have been able to conclude from this article, gale-force winds or simply gales (the term for these winds in their fullest strength), are not winds specifically associated with any particular weather system.
Rather, winds are classified as gale-force winds mainly because of the speed at which they travelling. (Not where they take place or how they are formed.)
Therefore as already stated earlier, winds measuring between 7 and 10 on the Beaufort Scale, indicating wind speeds of between 50 and 102 km/h (32 - 63 mph), are all considered to be gale-force winds.
We also touched on how these winds are generated, as well as briefly touching on the origins of the term to better understand its use.
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Until next time, keep your eye on the weather!