What wind speed is considered a hurricane?
The Saffir-Simpson Wind Scale — the key to understanding the power of hurricanes
Every year from early June to the end of November, a series of tropical cyclones occur in the Western Hemisphere. They are called «Hurricane Season». They come one after another from the Atlantic Ocean toward the coast of the United States and other countries, often reaching not only coastal but also continental areas.
As with other meteorological phenomena, different scales are used to determine hurricane strength, the most common of which is the Saffir-Simpson Hurricane Wind Scale (SSHWS). It has been familiar since childhood to anyone who lives on the South and East Coasts of the United States, but if you are only traveling to the region from another part of the world, you may be hearing about it for the first time.
In this article, we’ll tell what the Saffir-Simpson Hurricane Wind Scale is and how to read it so you know what to expect from cyclones.
What is Saffir-Simpson Hurricane Wind Scale?
The Saffir-Simpson Scale is a scale used to classify hurricanes — strong tropical cyclones in the Western Hemisphere. Knowing the category of a hurricane, help people to prepare for it, warn about it and minimize the damage from it.
The scale was invented in the United States in 1971 by two specialists: civil engineer Herbert Saffir and meteorologist Robert Simpson. It’s not hard to guess that the names of the scale are their last names. At the time the scale was created, the latter was also director of the US National Hurricane Center (NHC), the main hurricane forecasting and warning organization in the United States. Given its necessity and importance, the scale began to be used universally after two years.
The scale is only used to classify tropical cyclones, which occur in the Atlantic and North Pacific oceans. In the rest of the world other organizations use other scales, and hurricanes are called typhoons there. They can also occur in the seas — for example, Medicanes in the Mediterranean.
The full long name of the scale is often abbreviated for convenience: the Saffir-Simpson Hurricane Scale (SSHS), Saffir-Simpson Wind Scale (SSWS), or just the Saffir-Simpson Scale (SSS).
A huge tropical cyclone from space. Photo: Pexels
How to read Saffir-Simpson Hurricane Wind Scale?
The Saffir-Simpson Wind Scale is a simple scale that divides hurricanes into five categories. When we talk about the category of a hurricane, we talk about very strong wind, the basis of any storm. But hurricanes also bring heavy rain (downpoor), thunderstorms and lightning, and other kinds of extreme weather that the scale does not take into account.
For this reason, the scale is often criticized by some forecasters. The authors respond: «We don’t want to make it difficult to understand.»
So, to be considered a hurricane, a tropical cyclone must have a one-minute average maximum sustained wind of at least 33–42 m/s. Such winds are considered very dangerous, and stronger winds of 43–49 m/s are extremely dangerous. (Recall that winds are measured at 10 meters above sea level.) In this case, a tropical depression (less than 17 m/s, 38 mph, 62 km/h, 33 kn) or a tropical storm (18–32 m/s, 39–73 mph, 63–118 km/h, 34–63 kn), two types of weaker cyclones, are considered a Category 1 hurricane. Accordingly, the stronger it is, the higher its category — up to the strongest 5th. Beginning with the 3rd category, the hurricane is also assigned a «Major» type, which equals severe destruction.
The higher category also indicates the hurricane’s movements and its duration in time: the higher it is, the longer it lasts. «Minor hurricanes» of Categories 1–2 often end in just a few days or even bypass the coasts. Strong hurricanes of Categories 3–5 usually always reach the coasts and even continental areas and last about 5–7 days on average.
Hurricane strength is also often color-coded: blue for tropical depressions and storms, yellow and orange for hurricanes in Categories 1 through 3, and red for maximum Category 5 hurricanes.
According to History.com, «since 1924, there have been 35 documented hurricanes in the North Atlantic that reached this level. Five of them have hit the US at this maximum strength.»
Below we list all five categories of hurricanes and the impact they have according to the primary source — the National Hurricane Center (NHC) of the US National Oceanic and Atmospheric Administration (NOAA). Data from the center also allows you to know not only the actual wind strength of a particular hurricane but also the devastating effects that it brings.
Saffir-Simpson Hurricane Wind Scale. Valerya Milovanova / Windy.app
Category 1 hurricane — Some damage
Category 1 hurricane is a hurricane with a wind speed of 33–42 m/s (74–95 mph, 119–153 km/h, 64–82 kn). Such a hurricanes damages the roof of frame houses and their structural elements, breaks tree branches and uproots entire trees with shallow roots, and damages power lines, causing power outages or blackouts over large areas for up to several days.
Examples of Category 1 hurricanes include Irene in 1999 and Katrina in 2005.
Category 2 hurricane — Extensive damage
Category 2 hurricane is a hurricane with a wind speed of 43–49 m/s (96–110 mph, 154–177 km/h, 83–95 kn). Such a hurricanes significantly damages frame buildings, uproots bigger trees over much larger areas and destroys power grids, which usually take days to weeks to repair in certain hard-to-reach areas.
An example of a Category 2 hurricane is Frances in 2004.
Category 3 hurricane (major) — Devastating damage
Category 3 hurricane is a hurricane with a wind speed of 50–58 m/s (111–129 mph, 178–208 km/h, 96–112 kn). These hurricanes tear off the roofs of frame houses and cause other structural damage to buildings, uproot trees and block roads, and damage or destroy power lines that can take weeks to repair.
Examples of Category 3 hurricanes include King in 1950, Betsy in 1965, Jeanne in 2004, Irma in 2017, and many unnamed hurricanes between 1909 and 1945.
Category 4 hurricane (major) — Catastrophic damage
Category 4 hurricane is a hurricane with a wind speed of 58–70 m/s (130–156 mph, 209–251 km/h, 113–136 kn). Such a hurricane severely damages frame houses, including the loss of much of the structure (roof, walls), rips out most trees with their roots in the area, and also brings down power poles, resulting in a total loss of electricity for several weeks to a month or more.
Examples of Category 4 hurricanes are Donna in 1960 and many unnamed hurricanes between 1888 and 1947.
Category 5 hurricane (major) — Catastrophic damage
A category 5 hurricane is a hurricane with a wind speed of 70 m/s or higher (157 mph or higher, 252 km/h or higher, 137 kn or higher). Such a hurricanes destroys large numbers of frame houses entirely, breaks and moves trees that isolate entire neighborhoods, and causes a complete lack of electricity and problems restoring it, making large areas uninhabitable for months or more.
Examples of Category 5 hurricanes include Andrew in 1992, Felix in 2007, Matthew is 2016, and Maria in 2017.
Where to get a hurricane forecast?
You can find the hurricane forecast on the Weather Map in the Windy.app. To do this, select the Wind or Wind gust layer (rather than Precipitation or Waves), although it is by default.
A hurricane or typhoon can be defined as a small area on the map that stands out strongly due to its purple color in its center, indicating very high wind strength in the area. At the edges of the area, the colors change from purple through red and orange to yellow, green, and blue — that is, the farther from the center of the hurricane/typhoon, the lower the wind speed or wind gusts.
Typhoon Maysak 2020 in the Southeastern Asia the Windy.app for iOS
The colors of the map are commonly used to indicate wind speed. For convenience, you can change them to any other color you like.
Under the Units section in the app’s Settings, you can also select the wind speed units that are used in your region: meters per second, miles per hour, or knots.
Hurricanes can also be tracked on the Windy.app website on a similar Live Wind Map in the section of the same name.
Text: Ivan Kuznetsov, an outdoor journalist, editor and writer from the Dolomites, Italy, and Karelia, Finland, with 10 years of professional experience. His favorite sports are hiking, cycling and sauna. Read his other articles
Cover photo: George Desipris / Pexels
Hurricane vs. Typhoon
A cyclone is any mass of air that spirals around a low pressure center. It is an organized collection of thunderstorms embedded in a swirling mass of air. In general, both typhoons and hurricanes are tropical cyclones but differ in their locations. The difference between hurricane and typhoon is that tropical cyclones in the west Pacific are called Typhoons and those in the Atlantic and east Pacific Ocean are called Hurricanes. It’s the longitude that matters.
Comparison chart
Differences — Similarities —
| Hurricane | Typhoon | |
|---|---|---|
| About | A hurricane is a cyclone that is located in the North Atlantic Ocean, or the NE Pacific Ocean east of the International Date Line, or the South Pacific Ocean east of 160E, and with sustained winds that reach or exceed 74 mph. | Tropical cyclones in the Northwest Pacific Ocean west of the International Date Line with sustained winds of (or those that exceed) 74 mph are typhoons. |
| Rotation | Clockwise in the southern hemisphere and counterclockwise in the northern hemisphere | Clockwise in the southern hemisphere and counterclockwise in the northern hemisphere |
| Intensity | Hurricanes are classified into five categories according to the Saffir-Simpson Hurricane Wind Scale. The wind speed and intensity of damage increases as from category 1 to category 5. | Typhoons are generally very strong because of the Pacific’s warm water, and therefore are more frequent. They are also classified on the Saffir-Simpson Hurricane Wind Scale, but can also be classified on the Japan Meteorological Agency typhoon scal |
| Location | North Atlantic Ocean, the Northeast Pacific Ocean east of the International Date Line, or the South Pacific Ocean east of 160E. Hurricanes are found near the tropical zone, over warm waters in the Atlantic and Pacific ocean. | Northwest Pacific Ocean west of the International Date Line |
| Most affected areas | Caribbean Sea | South East Asia, China Sea etc. |
| Frequency | 10-15 per year | 25-30 per year |
| Occurrence | Usually warm areas | Usually warm areas |
| Characteristics | Heavy winds, floods, storm surge, a lot of rain, tornadoes | Heavy winds, floods, storm surge, a lot of rain, tornadoes |
| Forms of precipitation | Rain | Rain |
Hurricane Irene as seen from space
Speed of a Typhoon vs. Hurricane
A tropical cyclone is one in which the maximum sustained surface wind (using the U.S. 1-minute average) is generally 64 kt (74 mph or 119 km/hr) or more.
Differences in Location
The term hurricane is used for Northern Hemisphere tropical cyclones east of the International Date Line to the Greenwich Meridian. The term typhoon is used for Pacific tropical cyclones north of the Equator west of the International Date Line i.e. between 100E and 180E in the northern hemisphere.
Hurricane Isaac as seen from a NASA satellite on August 28, 2012.
Differences in Intensity
Typhoons are generally stronger than hurricanes. This is because of warmer water in the western Pacific which creates better conditions for development of a storm. This unlimited amount of warm water also makes for increased frequency of typhoons. Even the wind intensity in a typhoon is stronger than that of a hurricane but they cause comparatively lesser loss due to their location. However, both use the Saffir-Simpson Hurricane Wind Scale for classification.
Direction of Rotation
Some reports also suggest that typhoons can only be counterclockwise («anti-clockwise» in British English) while hurricanes can be both anti-clockwise and clockwise.
Areas where hurricanes and typhoons occur
Figures suggest the most common area for a Hurricane to occur is the Caribbean Sea while typhoons have a frequent occurrence off the coast of South East Asia.
Intensity Categories
Typhoons are tropical cyclones and are classified differently in various countries. Here’s how Japan classifies typhoons:
| Category | Sustained winds |
|---|---|
| Violent Typhoon | ≥105 knots ≥194 km/h |
| Very Strong Typhoon | 85–104 knots 157–193 km/h |
| Typhoon | 64–84 knots 118–156 km/h |
| Severe Tropical Storm | 48–63 knots 89–117 km/h |
| Tropical Storm | 34–47 knots 62–88 km/h |
| Tropical Depression | ≤33 knots ≤61 km/h |
Hurricanes are classified into 5 intensity categories using the Saffir-Simpson scale.
| Category | Wind speeds (for 1-minute maximum sustained winds) | |||
|---|---|---|---|---|
| meters per second | knots | miles per hour | kilometers per hour | |
| Five | ≥ 70 m/s | ≥ 137 kn | ≥ 157 mph | ≥ 252 km/h |
| Four | 58–70 m/s | 113–136 kn | 130–156 mph | 209–251 km/h |
| Three | 50–58 m/s | 96–112 kn | 111–129 mph | 178–208 km/h |
| Two | 43–49 m/s | 83–95 kn | 96–110 mph | 154–177 km/h |
| One | 33–42 m/s | 64–82 kn | 74–95 mph | 119–153 km/h |
Category 1 hurricanes cause minimal damage, category 2 cause moderate damage, category 3 cause extensive damage, category 4 hurricanes cause extreme damage, and category 5 hurricanes cause catastrophic damage.
Names of hurricanes and typhoons
Some commonly occurring hurricanes and typhoons have been named to categorize them. The names of Hurricanes are given each year. A few hurricanes named in the Atlantic in 2007 are Andrea, Barry and Dean. Some Typhoons named in the Western North Pacific and the South China Sea are Damrey, Langwang and Kirogi. Typhoons in the Chinese and Japanese regions are named after living things and often objects like flowers, rivers etc. Check out every hurricane name since 1950.
News about Hurricanes
External Links
- Hurricane Tracker — WSJ
