Cyclones of the Southern Hemisphere are measured by wind speed and assigned a category number. Whether or not they are classified as a cyclone is also determined by barometric pressure.
Wind speeds determine the category as follows:
Category 1: winds up to 125km/h
Category 2: 125- 170 km/h
Category 3: 170 - 225 km/h
Category 4: 225 - 280 km/h
Category 5: in excess of 280 km/h
Hurricanes, which are cyclones in the north-Western Hemisphere, are measured on the Saffir-Simpson scale. The categories are measured as follows:
Tropical Storm - Winds 39-73 mph
Category 1 Hurricane - winds 74-95 mph
Category 2 Hurricane - winds 96-110 mph
Category 3 Hurricane - winds 111-130 mph
Category 4 Hurricane - winds 131-155 mph
Category 5 Hurricane - winds 156 mph and up
A wind speed exceeding 74 miles per hour indicates a tropical storm. Prior to reaching this speed, a tropical system is categorized as a tropical depression or tropical disturbance based on its wind speeds and organization. Once wind speeds reach at least 39 miles per hour, it is classified as a tropical storm.
The determining factor is the sustained wind speed. If the tropical system has sustained winds of less than 39 miles per hour, then it is a tropical depression. If sustained winds are in the range of 39 to 73 mph, then it is a tropical storm. If sustained winds are 74 mph or faster, then it is a hurricane.
A tropical depression becomes a tropical storm when sustained winds reach 39 mph or greater.
A tropical depression is a tropical cyclone with winds under 39 mph. When winds reach or exceed that limit it is called a tropical storm and is given a name. Tropical depression 9 denotes the 9th tropical cyclone of that year in a particular ocean basin.
There is not set lower limit. A tropical depression, the weakest level of tropical cyclone is defined by having a closed Circulation. However. A tropical depression usually has sustained winds of at least 30 mph.
A knot in a tropical depression refers to the measure of wind speed within the system. One knot is equivalent to one nautical mile per hour. It is used to quantify the strength of the depression in terms of wind intensity.
A wind speed exceeding 74 miles per hour indicates a tropical storm. Prior to reaching this speed, a tropical system is categorized as a tropical depression or tropical disturbance based on its wind speeds and organization. Once wind speeds reach at least 39 miles per hour, it is classified as a tropical storm.
A tropical depression has winds under 39 mph.
The determining factor is the sustained wind speed. If the tropical system has sustained winds of less than 39 miles per hour, then it is a tropical depression. If sustained winds are in the range of 39 to 73 mph, then it is a tropical storm. If sustained winds are 74 mph or faster, then it is a hurricane.
A tropical depression has sustained winds of 38 mph or less.
There is no lower limit for tropical depression winds, which go up to 38 mph.
By measuring the sustained wind speed. If the wind speed of a tropical cyclone is anywhere in the range of 39 to 73 mph then it is a tropical storm. If the wind speed is 74 mph or greater then it is a hurricane.
A tropical depression is a weak tropical cyclone wind sustained winds of less than 39 miles per hour. As the depression is fueled by moisture from warm ocean water it gains strength and becomes more organized. When wind speeds reach 39 mph it becomes a tropical storm. When they reach 74 mph it becomes a hurricane.
The determining factor is the sustained wind speed. If the tropical system has sustained winds of less than 39 miles per hour, then it is a tropical depression. If sustained winds are in the range of 39 to 73 mph, then it is a tropical storm. If sustained winds are 74 mph or faster, then it is a hurricane.
A tropical depression becomes a tropical storm when sustained winds reach 39 mph or greater.
A tropical depression is a tropical cyclone with winds under 39 mph. When winds reach or exceed that limit it is called a tropical storm and is given a name. Tropical depression 9 denotes the 9th tropical cyclone of that year in a particular ocean basin.
All tropical cyclones are considered tropical storms when wind reach 39 mph