how do hurricanes form?
Our understanding of the formation of hurricanes and other tropical storms is still expanding. There are a variety of theories in circulation about how hurricanes form, but there is no definite answer at this point in time. Thanks to a variety of research projects, scientists have been able to isolate six factors which appear to be the necessary conditions required for the formation of any tropical storm. There are some tropical storms that can gain strength without meeting each of these six factors.
Hurricanes form in tropical regions where there is warm water (at least 80 degrees Fahrenheit / 27 degrees Celsius), moist air and converging equatorial winds. Most Atlantic hurricanes begin off the west coast of Africa, starting as thunderstorms that move out over the warm, tropical ocean waters. A thunderstorm reaches hurricane status in three stages: Tropical depression – swirling clouds and rain with wind speeds of less than 38 mph (61.15 kph / 33 kt) Tropical storm – wind speeds of 39 to 73 mph (54.7 to 117.5 kph / 34 to 63 kt) Hurricane – wind speeds greater than 74 mph (119 kph / 64 kt) It can take anywhere from hours to several days for a thunderstorm to develop into a hurricane.
Hurricanes usually form in the summer or early autumn when several key atmospheric ingredients come together. Contrary to common belief, many factors other than warm ocean water cause hurricanes to form. In fact, the water is always warm enough in the deep tropics for hurricanes to form all year long. During the winter and spring, upper air winds are hostile, and usually do not allow tropical cyclone development. So, what does it take for a hurricane to form? • 1. Pre-existing Disturbance or low pressure area must have formed in the low levels of the atmosphere to start winds converging and uplift. • 2. Warm Water to a sufficient depth to support the energy that a hurricane will use. The threshold temperature for tropical cyclone development needs to be about 26.5º Celsius or 80º Fahrenheit. A water column depth of about 50 meters or 150 feet deep is required. • 3. Low Stability will allow deep convection or cumulonimbus clouds to build to great heights in the atmosphere.
Hurricanes usually form in the summer or early autumn when several key atmospheric ingredients come together. Contrary to common belief, many factors other than warm ocean water cause hurricanes to form. In fact, the water is always warm enough in the deep tropics for hurricanes to form all year long. During the winter and spring, upper air winds are hostile, and usually do not allow tropical cyclone development. So, what does it take for a hurricane to form? The ingredients for hurricane formation • 1. Pre-existing Disturbance or low pressure area must have formed in the low levels of the atmosphere to start winds converging and uplift. • 2. Warm Water to a sufficient depth to support the energy that a hurricane will use. The threshold temperature for tropical cyclone development needs to be about 26.5 Celsius or 80 Fahrenheit. A water column depth of about 50 meters or 150 feet deep is required. • 3.
Ingredients for hurricane formation Hurricanes usually form in the summer or early autumn when several key atmospheric ingredients come together. Contrary to common belief, many factors other than warm ocean water cause hurricanes to form. In fact, the water is always warm enough in the deep tropics for hurricanes to form all year long. During the winter and spring, upper air winds are hostile, and usually do not allow tropical cyclone development. So, what does it take for a hurricane to form? • 1. Pre-existing Disturbance or low pressure area must have formed in the low levels of the atmosphere to start winds converging and uplift. • 2. Warm Water to a sufficient depth to support the energy that a hurricane will need. The temperature needs to be about 26.5 Celsius or 80 Fahrenheit to a depth of about 50 meters or 150 feet deep. • 3. Low Stability will allow deep convection or cumulonimbus clouds to build to great heights in the atmosphere.
