Wind Speeds That Can Lift a Human Off the Ground

Understanding the conditions under which wind can lift a human off the ground is crucial, especially during severe storms and extreme weather events such as hurricanes or tornadoes. The wind speed required to achieve this can vary based on several factors, including a person's weight, body position, and environmental conditions. In this article, we explore the specific wind speeds that can potentially lift a person off the ground and discuss the safety measures to be considered during such conditions.

Factors Influencing Wind Lift

The ability of wind to lift a person off the ground depends on a combination of their weight, body posture, and how they brace themselves against the wind.

Light Winds and Vulnerability

As a general guideline, wind speeds of around 40 to 50 mph (64 to 80 km/h) can start to lift lighter individuals, particularly if they are not bracing themselves or in a vulnerable position. For example, during the severe storms in Carlisle on 26–29 December 1997, a person weighing around 55 kg was lifted off the ground for a step or two at a time due to gusty winds. This demonstrates the potential for light and gusty winds to lift a person, even if they are not in immediate harm.

High Winds and Risk

Wind speeds of 60 mph (97 km/h) or higher can pose a significant risk, especially for smaller individuals or those in more exposed positions. Extreme weather conditions, such as hurricanes or tornadoes, can drastically exceed these thresholds, making it extremely dangerous to be outdoors. For instance, in Category 4 hurricanes, which have winds between 130 and 156 mph, it becomes nearly impossible to walk, with people being pushed along the ground rather than moving at their own pace.

Supersonic Winds and Disaster

Tornadoes, with recorded winds over 300 mph (483 km/h), are known to have the capability to lift vehicles off the ground. These powerful storms, classified as EF5, can cause catastrophic damage and pose a severe threat to human safety. In comparison, the terminal velocity of the human body, in a stable position, is around 200 km/h (124 mph), making it likely that these wind speeds would push a person around on the ground and make it very difficult to walk.

Personal Tales and Wind Experiences

While the theoretical understanding of wind speeds that can lift a person is important, personal experiences also play a significant role in appreciating the power of wind. For example, a person recounting their experience of being lifted off the ground by a wind gust in Carlisle highlights the real-world implications of such high wind speeds. Such anecdotes provide a visceral understanding of the potential risks involved during severe weather events.

Formulas and Calculations

To calculate the specific wind speed that can lift a person off the ground, we can use a formula provided by researchers E. Linacre and B. Geerts. According to their calculations, a person with a weight of 62 kg (136.6 pounds) and a surface area of 1.9 m2 (20.45143 feet2) would require a wind speed of approximately 66.12 km/h (41.08623 mph) to be lifted off the ground. It is worth noting that this calculation can vary based on individual body characteristics and environmental factors.

Conclusion and Safety Measures

While high wind speeds can be awe-inspiring, they also pose significant risks to human safety. During severe storms, it is crucial to stay indoors and avoid being in exposed or elevated positions. Understanding the wind speeds that can lift a person, and the associated risks, is essential for staying safe during extreme weather conditions. Whether you are in an airplane or on the ground, awareness and preparedness are key to ensuring your safety.

Keywords

Keywords: wind speed, storm safety, terminal velocity.