When comparing a tropical depression vs tropical storm, it is quite natural to feel confused.
Tropical depressions and tropical storms are two frequently used terms in the domain of tropical weather systems.
Meteorological phenomena have a significant impact on the formation and progression of tropical cyclones.
It is essential to comprehend the differences between tropical storm vs tropical depression to accurately predict weather patterns.
So, how do you compare tropical storm vs depression?
Both tropical depressions and tropical storms come from warm oceanic regions but are different in terms of wind speeds and organization.
Overview of Tropical Depression and Tropical Storm
Clusters of thunderstorms develop over warm tropical oceans, where they linger as tropical depressions.
When the air pressure falls, the thunderstorms are forced into a rotation forming a tropical cyclone.
Such rotating systems are often described as an atmospheric heat engine fueled by the exchange of warm water.
Once formed they generate huge amounts of energy that continue to intensify forming spiraling rainbands around a central eye.
The impact of cyclones can be significant, particularly on the coast but also far inland.
It can cause damage to property and loss of life whilst disrupting economic activity, particularly in the transport and agricultural sectors.
A tropical depression is an area of heavy rains and winds and is the first stage in the development of a hurricane.
It is one of four kinds of storm referred to collectively as tropical cyclones, the group includes major hurricanes.
All tropical cyclones develop over subtropical waters sometimes into vast rotating systems, rotating counterclockwise in the northern hemisphere and clockwise in the southern.
A storm transitions through the four storm categories as its winds gather speed.
A tropical depression is the first stage of eventual hurricane formation. A tropical storm is the second.
Fact: By digging deeper into the details, it becomes evident that tropical depressions usually have a less defined circulation pattern as compared to tropical storms.
Understanding More about Tropical Depression Vs Tropical Storm
When talking about weather events such as tropical storms or depression, it is important to pay attention to their wind speeds and the destruction they can cause.
Let’s talk about more of those differences that help you separate tropical storms from depressions:
Comparing Tropical Depression and Tropical Storm
The climate in the tropical zones is responsible for generating much of our planet’s weather.
They are much closer to the sun which shines directly down onto warm shallow seas.
With high temperatures, the air is thick with water vapor and an endless supply of ocean water and heat makes the atmosphere warm and humid all year round.
Once temperatures exceed 27oC, if conditions are right, a tropical depression can form.
And if optimal conditions continue, the depression is upgraded to a tropical storm once its winds reach speeds that organize them into fast moving air currents around the low-pressure center.
Differences in Wind Speed Between Tropical Storm and Tropical Depressions
It is the speed of a tropical cyclone’s winds and the damage caused that determines a storm’s classification.
For a weather system to be classified as a depression or tropical wave, disturbance, or feature as referred to by weather reporters, gusting wind speeds must be less than 38 mph.
Gusts typically last just a few seconds. To be upgraded to a tropical storm, the depression’s winds must have a sustained speed of between 39 and 73 mph.
This is measured over two minutes.
Categorization Based on Wind Speeds
Meteorologists categorize storms according to the Saffir-Simpson Scale Wind Scale.
This scale gives the storm a 1 – 5 rating based on wind speed which is correlated with an informed estimation of the impact on the property.
Because the weather system moves, conditions often change, for example the water may be cooler.
Therefore, not all depressions develop into tropical storms and not all tropical storms become hurricanes.
Differences in Structure and Appearance
Regardless of wind speeds, all tropical cyclones are rotating masses of air that are warm at their core and circle low pressure systems in a spiral.
The air current takes in warm moist air at sea level and this latent heat forces the air upwards into the thinner cold air.
The heat is lost to the atmosphere and the water vapor condenses into a cloud and the now cold current descends to begin the cycle again.
As well as being regulated by temperature the cycle is also regulated by air pressure.
An Important Consideration
As a cyclone transitions from depression to storm the falling atmospheric pressure drives the wind faster.
The center becomes better defined as the pressure difference between the bottom and top of the cycling air increases resulting in faster winds speeds in nature’s attempt to equalize it.
Fact: The clouds grow denser, darker and taller as more water vapor condenses out to coalesce into water droplets.
Differences in Potential for Damage and Destruction
Overland, tropical cyclones are no longer fueled by warm moist air. Eventually, the winds slow, pressure equalizes and the storm dissipates.
With their higher pressures and slower wind speeds tropical depressions do not cause the damage to property typical of the other storms in the group.
Even so, they drop a considerable amount of rain with the potential for severe flooding.
The heavy rain contributes to coastal erosion either via run off or by the coastline being pummeled by the wind-driven waves.
Tropical storms can reach near hurricane-speed winds, but even as newly upgraded storms their wind speeds are dangerous.
An Important Consideration
According to the Beaufort Wind Scale, in winds of 39 to 46 mph walking is difficult, twigs and branches are broken from trees and moderately high waves form.
Between 64 and 72 mph, still classified as a tropical storm although a violent one, waves are bigger, visibility poor, and widespread property damage is typical.
Fact: Both tropical depression and storm have spiral rainbands but are usually missing in tropical depressions and are almost always present in organized tropical storms.
Differences in Warning and Preparation Guidelines
In the US, The National Hurricane Center announces a Tropical Storm Watch.
They do it when the conditions in an approaching depression indicate it has the potential to sustain winds of between 39 and 73 mph within the next 48 hours.
It is followed by a Tropical Storm Warning and the likelihood is more certain within the remaining 36.
The next level is a hurricane watch and then a hurricane warning.
The main treats to daily life associated with all tropical cyclones include:
- Storm surges
- High winds
- Heavy rain
- Fierce rip currents
The risks and severity increase the lower the pressure falls and the more time the storm has to develop before hitting land.
An Important Consideration
Most storms will dissipate long before they make landfall and thankfully, major hurricanes are relatively rare.
However, with the impact of climate change the frequency and intensity of tropical cyclones seems to be increasing globally.
Importance of Understanding the Differences Between Tropical Storm and Tropical Depression
It is extremely important to understand the basic differences between tropical depression and storm.
The information helps you to be ready for emergencies and effectively communicate potential consequences to areas that may be affected.
Although both hurricanes and typhoons have their origins in warm oceanic regions, the primary factors that distinguish them are their wind speeds and organization.
Life can continue relatively unhindered on a blustery day, but a moderate 45-50 mph tropical storm could bring everything to a holt just as easily as a hurricane.
People are being urged to attend to their storm preparedness.
The National Weather Service issued a 6-point guide, which involves the following information:
- Be sure to check the forecast regularly.
- Signup for local weather warnings.
- Have a family plan so everyone knows where to go and what to do.
- Practice the family plan.
- Prepare the home, securing loose objects, removing dead branches, closing all the windows and doors.
- Help neighbors prepare and taking first aid training.
Fact: A tropical depression is less likely to produce heavy rainfall and thunderstorm activity as compared to a tropical storm.
Learning to compare tropical depression vs tropical storm is important.
Although both come from warm oceanic regions and have similarities, the main distinguishing factor is their wind speeds and organization.
Tropical depressions are characterized by weaker wind speeds and less structured formations when compared to tropical storms.
By comprehending these differences, meteorologists can precisely evaluate the strength and possible consequences of tropical cyclones.