Featured Image: GC Map

Most Turbulent Routes in the World: An In-Depth Analysis

DALLAS – Flights aren’t always smooth sailing, and navigating the skies can be particularly challenging for pilots and unsettling for passengers on certain routes that are known for their high turbulence levels. While the Santiago (SCL) to Santa Cruz (VVI) route currently tops the list as the most turbulent with an average EDR of 17.568, numerous flights globally are affected by turbulent conditions, according to the Turbli database. 

According to recent data from Turbli, these routes experience significant turbulence due to a combination of landscape features, climatic conditions, and jet stream positions. For instance, the higher turbulence level at the SCL to Santa Cruz route is largely due to the Pacific and Atlantic winds crossing the Andes at right angles, creating intense mountain wave turbulence. Pilots flying this route must be able to handle sudden and severe air movements caused by the rugged terrain below.

Moreover, flights departing from Tokyo often encounter significant turbulence on long-haul routes. Similarly, some of the regions that are prone to turbulence include the equator, which is known for strong vertical air currents and frequent thunderstorms.

9V-SWJ Singapore Airlines Boeing 777-300(ER) Star Alliance Livery. Photo: Luca Flores/Airways

Understanding Turbulence

Turbulence is the erratic movement of air that causes rough or bumpy conditions during a flight. It can range from light, barely noticeable movements to severe jolts that can cause discomfort and even injury (sometimes fatality). Several factors including atmospheric pressure, jet streams, weather fronts, thunderstorms, and geographic features such as mountains and bodies of water cause turbulence time and often.

Before moving toward the most turbulent routes, let’s briefly discuss about the major types of turbulences, their causes, and the routes affected by the particular type of turbulence.

1. Clear Air Turbulence (CAT)

   - Cause: Occurs in clear skies near jet streams due to sudden changes in wind speed or direction at high altitudes. CAT is particularly dangerous because it is invisible and can occur without any visual warning signs, making it difficult for pilots to anticipate.

   - Routes Affected: Long-haul flights over the Pacific, such as those from Tokyo to North America, often encounter CAT due to the presence of strong jet streams.

2. Mountain Wave Turbulence

   - Cause: When wind flowing over mountains creates waves of air on the downwind side, this turbulence is felt. This type of turbulence can extend far downwind of the mountains and can affect flights even at high altitudes.

   - Routes Affected: Flights over the Andes, such as Santiago (SCL) to Santa Cruz (VVI), frequently experience mountain wave turbulence due to the interaction between wind and the rugged terrain.

ET-AWP - Ethiopian Airlines - Airbus A350-900 (A359) - ZRH LSZH. Photo: Rohan Ramalingam/Airways

3. Thermal Turbulence

   - Cause: Surface heating causes rising warm air (thermals), leading to thermal turbulence. It is most common over land during the daytime, especially in regions with intense solar heating.

   - Routes Affected: Equatorial routes, such as those across Africa and South America, where the sun’s heat generates strong vertical air currents.

4. Mechanical Turbulence

   - Cause: Wind flows over or around obstacles like buildings, trees, or rough terrain, causing disruptions in the airflow. This type of turbulence is often experienced during takeoff and landing, particularly in urban areas or near large structures, and buildings.

   - Routes Affected: Urban areas or routes near large structures and varying terrains, such as flights into and out of airports surrounded by mountainous terrain or skyscrapers.

5. Convective Turbulence

   - Cause: Thunderstorms and convective weather systems causing strong updrafts and downdrafts. This turbulence is associated with severe weather and can cause sudden and violent movements.

   - Routes Affected: Equatorial regions and areas prone to frequent thunderstorms, such as flights through the Intertropical Convergence Zone (ITCZ).

Turkish Airlines TC-JOL Airbus A330-303. Photo: Lorenzo Giacobbo/Airways

Global Top 10 Turbulent Routes

The most turbulent routes listed below are ranked based on the eddy dissipation rate (EDR), a measure of turbulence intensity at a specific location, as stated by Turbli founder Ignacio Gallego Marcos. These routes exhibit high turbulence levels due to a combination of landscape features, climatic conditions, and jet stream positions, as revealed by Turbli's database.

Following closely behind the Santiago (SCL) to Santa Cruz (VVI) route, which is the most turbulent route is the Almaty (ALA) to Bishkek (FRU) route, which experiences significant turbulence due to its proximity to the Tien Shan mountain range. The complex interaction between mountain-induced turbulence and varying weather patterns make this route one of the most challenging ones.

Similarly, in China, high-altitude routes such as Lanzhou (LHW) to Chengdu (CTU) and Xianyang (XIY) to CTU are also prone to turbulence. These routes are influenced by the Tibetan Plateau, which can lead to strong vertical air currents and severe turbulence. The presence of mountain ranges and the unique weather patterns of this region contribute to the frequent and intense turbulence experienced on these flights.

Top 10 Most Turbulent Routes in the World. Photo: GC Map

Japan’s turbulent routes, including Centrair (NGO) to Sendai (SDJ) and Osaka (KIX) to SDJ, are impacted by the country's complex weather systems, which are influenced by surrounding seas and mountain ranges. These routes often encounter clear air turbulence (CAT), caused by sudden changes in wind speed or direction at high altitudes, especially near jet streams. 

European routes like Milan (MXP) to Geneva (GVA) and Zurich (ZRH) are also frequently turbulent due to their proximity to the Alps. The mountainous terrain in this region creates significant atmospheric disturbances, resulting in mountain wave turbulence that can sometimes make flights over these regions particularly rough.

Overall, these most turbulent routes reveal the diverse and challenging conditions that can affect flights worldwide. Understanding the specific causes and types of turbulence on these routes can help in better managing and preparing for a safe flight. 

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :----------------------------------- | :------------ | :-------------------- | | 1 | Santiago (SCL) - Santa Cruz (VVI) | 1905 | 17.568 | | 2 | Almaty (ALA) - Bishkek (FRU) | 210 | 17.457 | | 3 | Lanzhou (LHW) - Chengdu (CTU) | 661 | 16.75 | | 4 | Centrair (NGO) - Sendai (SDJ) | 517 | 16.579 | | 5 | Milan (MXP) - Geneva (GVA) | 214 | 16.398 | | 6 | Lanzhou (LHW) - Xianyang (XIY) | 519 | 16.337 | | 7 | Osaka (KIX) - Sendai (SDJ) | 655 | 16.307 | | 8 | Xianyang (XIY) - Chengdu (CTU) | 624 | 16.25 | | 9 | Xianyang (XIY) - Chongqing (CKG) | 561 | 16.041 | | 10 | Milan (MXP) - Zurich (ZRH) | 203 | 16.016 |
N501DN Delta Air Lines Airbus A350-941 Photo: Luca Flores/Airways

Most Turbulent Routes in North America

North America’s turbulence hotspots are heavily influenced by the continent's varied topography and weather systems. The Rocky Mountains, the Appalachian Mountains, and frequent weather disturbances contribute significantly to turbulence experienced on these routes. 

Based on EDR, with an average EDR of 14.728, the Nashville (BNA) to Raleigh/Durham (RDU) route tops the list in the region with high turbulence levels due to the frequent weather systems and the influence of the Appalachian Mountains. Pilots on this route must be particularly vigilant for mechanical and thermal turbulence, especially during the summer months when convective weather is common.

The Charlotte (CLT) to Pittsburgh (PIT) route also experiences significant turbulence levels, primarily due to the interaction between different air masses and the region's mountainous terrain. Whereas, the Denver (DEN) to Puerto Vallarta (PVR) route faces challenges from the Rocky Mountains, combined with thermal turbulence over Mexico. 

Top 10 Most Turbulent Routes in North America. Photo: GC Map

Moreover, on the East Coast, particularly routes involving New York (JFK) to RDU, experience considerable turbulence due to frequent weather systems and the Appalachian Mountains. Routes from Warwick (PVD) to Syracuse (SYR) and Atlanta (ATL) to Dulles (IAD) are also affected by turbulence. These routes are impacted by varying terrain and weather patterns, requiring pilots to be prepared for sudden changes in air movement. 

Similarly, flights from PIT to RDU and New York (LGA) to Portland (PWM) often encounter turbulence due to mechanical and thermal factors. The combination of urban environments, varying terrains, and changing weather patterns contribute to the frequent turbulence on these routes.

As a whole, North America's turbulent routes are influenced by a combination of geographical features and weather patterns. The presence of mountain ranges, frequent weather disturbances, and varying terrains make these routes particularly challenging for pilots and passengers alike. Understanding the specific causes of turbulence on these routes can help in better managing and preparing for a smooth flight.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :------------------------------------ | :------------ | :-------------------- | | 1 | Nashville (BNA) - Raleigh/Durham (RDU) | 711 | 14.728 | | 2 | Charlotte (CLT) - Pittsburgh (PIT) | 589 | 14.582 | | 3 | Denver (DEN) - Puerto Vallarta (PVR) | 2127 | 14.535 | | 4 | New York (JFK) - Raleigh/Durham (RDU) | 686 | 14.517 | | 5 | Warwick (PVD) - Syracuse (SYR) | 414 | 14.494 | | 6 | Atlanta (ATL) - Dulles (IAD) | 859 | 14.492 | | 7 | Pittsburgh (PIT) - Raleigh/Durham (RDU) | 527 | 14.478 | | 8 | New York (LGA) - Portland (PWM) | 433 | 14.457 | | 9 | Boston (BOS) - Syracuse (SYR) | 425 | 14.453 | | 10 | Boston (BOS) - Philadelphia (PHL) | 450 | 14.453 |
CC-CXH LATAM Boeing 767-316(ER)(WL). Photo: Otto Kirchof/Airways

Most Turbulent Routes in South America

In South America, the most turbulent routes are heavily influenced by the Andes and coastal winds. Besides, the Santiago (SCL) to Santa Cruz (VVI) route, other routes in South America that experience high turbulence levels include Florianópolis (FLN) to SCL and FLN to Ciudad de la Costa (MVD), with an average EDR of 15.307 and 15.224 respectively. These routes are influenced by the complex weather patterns and geographical features of the region, which contribute to frequent and intense turbulence. 

Additionally, the SCL to Asunción (ASU) route experiences significant turbulence due to the Andes and varying climatic conditions in the region. Buenos Aires (EZE) to SCL and EZE to FLN are also affected by the Andes and coastal winds, creating challenging flying conditions.

Top 10 Most Turbulent Routes in South America. Photo: GC Map

Santiago (SCL) emerges as a central hub for the most turbulent routes in South America. In addition to the above-mentioned routes, flights from SCL to various destinations, such as MVD and São Paulo (GRU), often encounter turbulence due to the region's unique weather patterns and topographical features. The Rio De Janeiro (GIG) to SCL route also experiences high turbulence levels, influenced by the interaction between oceanic winds and mountainous terrain.

In conclusion, South America's turbulent routes are heavily influenced by the Andes and coastal winds. The complex interaction between geographical features and weather patterns creates challenging flying conditions, requiring advanced forecasting and careful route planning to ensure safe and comfortable flights.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :---------------------------------------------- | :------------ | :-------------------- | | 1 | Santiago (SCL) - Santa Cruz (VVI) | 1905 | 17.568 | | 2 | Florianópolis (FLN) - Santiago (SCL) | 2220 | 15.307 | | 3 | Florianópolis (FLN) - Ciudad de la Costa (MVD) | 1066 | 15.224 | | 4 | Santiago (SCL) - Asunción (ASU) | 1571 | 15.162 | | 5 | Buenos Aires (EZE) - Santiago (SCL) | 1140 | 15.124 | | 6 | Buenos Aires (EZE) - Florianópolis (FLN) | 1236 | 15.076 | | 7 | Santiago (SCL) - Ciudad de la Costa (MVD) | 1369 | 14.993 | | 8 | São Paulo (GRU) - Santiago (SCL) | 2617 | 14.892 | | 9 | São Paulo (GRU) - Ciudad de la Costa (MVD) | 1567 | 14.85 | | 10 | Rio De Janeiro (GIG) - Santiago (SCL) | 2937 | 14.791 |
HB-JMB SWISS Airbus A340-313X. Photo: Alberto Cucini/Airways

Most Turbulent Routes in Europe

Moving towards Europe, the most turbulent routes are particularly influenced by the Alps and varying weather patterns across the region. Zurich (ZRH) appears frequently in the list of most turbulent routes, indicating its exposure to turbulent conditions influenced by the surrounding Alps. The Milan (MXP) to Geneva (GVA) route is the most turbulent route in Europe with an average EDR of 16.398, primarily due to the proximity to the Alps, which create significant atmospheric disturbances. While flying over this route, one must navigate the challenges posed by mountain wave turbulence and varying weather patterns.

Flights operating from MXP to ZRH also experience significant turbulence with an average EDR of 16.016, influenced by the Alps and the region's complex weather systems. The GVA to ZRH route is similarly affected, with frequent turbulence caused by the mountainous terrain and varying climatic conditions. Other routes in Europe, such as Marseille (MRS) to ZRH and Zgornji Brnik (LJU) to ZRH, also experience significant turbulence.

Top 10 Most Turbulent Routes in Europe. Photo: GC Map

Flights from Nice (NCE) to Basel (BSL) and NCE to ZRH encounter turbulence due to the complex interaction between coastal winds and the mountainous terrain. The Yerevan (EVN) to Tbilisi (TBS) route is influenced by the Caucasus Mountains, creating challenging flying conditions with frequent turbulence. Routes from BSL to Venezia (VCE) and Frankfurt am Main (FRA) to Caselle Torinese (TRN) are also notable for their turbulence levels in Europe, particularly influenced by the Alps and surrounding weather patterns.

In summary, Europe’s turbulent routes are heavily influenced by the Alps and complex weather patterns. The presence of mountain ranges and varying climatic conditions create challenging flying conditions in this region.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :----------------------------------------- | :------------ | :-------------------- | | 1 | Milan (MXP) - Geneva (GVA) | 214 | 16.398 | | 2 | Milan (MXP) - Zurich (ZRH) | 203 | 16.016 | | 3 | Geneva (GVA) - Zurich (ZRH) | 230 | 14.964 | | 4 | Marseille (MRS) - Zurich (ZRH) | 517 | 13.987 | | 5 | Zgornji Brnik (LJU) - Zurich (ZRH) | 471 | 13.878 | | 6 | Nice (NCE) - Basel (BSL) | 438 | 13.876 | | 7 | Nice (NCE) - Zurich (ZRH) | 434 | 13.76 | | 8 | Yerevan (EVN) - Tbilisi (TBS) | 175 | 13.758 | | 9 | Basel (BSL) - Venezia (VCE) | 437 | 13.713 | | 10 | Frankfurt am Main (FRA) - Caselle Torinese (TRN) | 541 | 13.653 |
JA848J Japan Airlines Boeing 787-8 Dreamliner. Photo: Nick Sheeder/Airways

Most Turbulent Routes in Asia

Similar to other regions, Asia’s turbulent routes are also influenced by mountainous regions and monsoon systems. As compared to others, flights originating or arriving at Xianyang (XIY) frequently pose a high risk of turbulence, highlighting the impact of China’s complex terrain on turbulence levels. The Almaty (ALA) to Bishkek (FRU) route is the most turbulent route in Asia with an average EDR of 17.457, highly influenced by the Tien Shan mountain range and varying weather patterns. 

The Lanzhou (LHW) to Chengdu (CTU) route experiences significant turbulence due to the influence of the Tibetan Plateau and surrounding weather patterns. Flights from Centrair (NGO) to Sendai (SDJ) and Osaka (KIX) to SDJ are also prone to turbulence, influenced by Japan’s complex weather systems and surrounding seas. The LHW to XIY route is similarly affected by the region’s unique topographical features and weather patterns. 

Top 10 Most Turbulent Routes in Asia. Photo: GC Map

Routes from XIY to CTU and XIY to Chongqing (CKG) also experience significant turbulence due to the influence of China’s complex terrain and weather systems. Moreover, the Wuhan (WUH) to XIY route is influenced by the interaction between different air masses and the region’s topographical features. Other Japanese routes, such as KIX to Fukuoka (FUK) and Tokyo (NRT) to Osaka (ITM), are impacted by the region’s unique weather patterns and complex terrain.

Therefore, Asia’s turbulent routes are influenced by mountainous regions and monsoon systems. The presence of complex terrain and varying weather patterns creates challenging flying conditions. As compared to other regions where only a few routes have an average EDR above 16 points, Asia has eight routes with an average EDR, north of 16 points.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :----------------------------------------- | :------------ | :-------------------- | | 1 | Almaty (ALA) - Bishkek (FRU) | 210 | 17.457 | | 2 | Lanzhou (LHW) - Chengdu (CTU) | 661 | 16.75 | | 3 | Centrair (NGO) - Sendai (SDJ) | 517 | 16.579 | | 4 | Lanzhou (LHW) - Xianyang (XIY) | 519 | 16.337 | | 5 | Osaka (KIX) - Sendai (SDJ) | 655 | 16.307 | | 6 | Xianyang (XIY) - Chengdu (CTU) | 624 | 16.25 | | 7 | Xianyang (XIY) - Chongqing (CKG) | 561 | 16.041 | | 8 | Wuhan (WUH) - Xianyang (XIY) | 654 | 16.008 | | 9 | Osaka (KIX) - Fukuoka (FUK) | 452 | 15.974 | | 10 | Tokyo (NRT) - Osaka (ITM) | 463 | 15.955 |
VH-QPD Qantas Airbus A330-303. Photo: Noah Pitkin/Airways

Most Turbulent Routes in Oceania

In Oceania, the turbulence experienced on various flight routes is mainly influenced by the region’s unique weather patterns and geographical features. The Brisbane (BNE) to Sydney (SYD) route is the most turbulent route in the region, with an average EDR of 15.31. This route is particularly turbulent due to the interaction between oceanic winds from the Tasman Sea and the varying weather conditions over the East Australian coastline. The frequent weather changes and the presence of the Great Dividing Range add to the complexity, making this route one of the most challenging one.

The Port Vila (VLI) to Auckland (AKL) route also experiences notable turbulence, with an average EDR of 14.039 due to interaction between tropical air masses and oceanic winds from the South Pacific Ocean. Additionally, flights from Melbourne (MEL) to SYD are influenced by the Great Dividing Range and coastal winds, which can lead to severe turbulence, especially during certain weather conditions.

Top 10 Most Turbulent Routes in Oceania. Photo: GC Map

Flights from VLI to BNE and VLI to SYD also encounter significant turbulence due to the tropical climate and the influence of oceanic winds. These routes, with average EDRs of 13.874, face the added challenge of navigating through weather systems associated with the South Pacific Ocean, which can be unpredictable and severe. Similarly, the VLI to MEL route is affected by the crossing of the Tasman Sea and the interaction of tropical and temperate air masses. This creates conditions conducive to clear air turbulence (CAT), especially at higher altitudes.

Furthermore, routes from BNE to MEL, ADL, and Darwin (DRW) are also notable for their turbulence levels, due to the influence of the Great Dividing Range and the combination of desert landscapes, coastal influences, and varying air masses. Lastly, the AKL to Christchurch (CHC) route, with an average EDR of 13.457, is influenced by the Southern Ocean and New Zealand’s mountainous terrain. The crossing of the Cook Strait and the interaction with the prevailing westerly winds, known as the Roaring Forties, contribute to the turbulence experienced on this route.

In summary, Oceania’s most turbulent routes are largely influenced by the interaction between oceanic winds and the region’s unique geographical features. The presence of the Tasman Sea, the South Pacific Ocean, and the mountainous terrain of New Zealand creates frequent and intense turbulence.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :--------------------------------- | :------------ | :-------------------- | | 1 | Brisbane (BNE) - Sydney (SYD) | 750 | 15.31 | | 2 | Port Vila (VLI) - Auckland (AKL) | 2232 | 14.039 | | 3 | Melbourne (MEL) - Sydney (SYD) | 705 | 14.009 | | 4 | Port Vila (VLI) - Brisbane (BNE) | 1893 | 13.874 | | 5 | Port Vila (VLI) - Sydney (SYD) | 2481 | 13.874 | | 6 | Port Vila (VLI) - Melbourne (MEL) | 3185 | 13.86 | | 7 | Brisbane (BNE) - Melbourne (MEL) | 1379 | 13.784 | | 8 | Brisbane (BNE) - Adelaide (ADL) | 1621 | 13.586 | | 9 | Brisbane (BNE) - Darwin (DRW) | 2848 | 13.56 | | 10 | Auckland (AKL) - Christchurch (CHC) | 744 | 13.457 |
ZS-SXB South African Airways Airbus A340-313. Photo: Brandon Farris/Airways

Most Turbulent Routes in Africa

Moving towards Africa, the most turbulent routes in this region are influenced by a combination of desert landscapes, highland regions, and weather systems. The route from Cape Town (CPT) to Durban (DUR) tops the list with an average EDR of 14.894. The turbulence on this route is primarily influenced by the Drakensberg Mountains. The wind patterns interacting with these mountains create mechanical turbulence, which can be quite severe. Additionally, the coastal proximity contributes to variable weather conditions, adding to the turbulence.

The CPT to Mpaka (SHO) route is another highly turbulent route, with an average EDR of 14.633. The interaction between the oceanic and inland air masses over this route creates challenging conditions for pilots. The varying terrain and the influence of the Mozambique Channel contribute to the turbulence experienced on this route. Similarly, flights from CPT to Maputo (MPM) are prone to turbulence due to the complex weather patterns over the region. In Africa, the combination of coastal winds and the heating of the ground during the day leads to significant thermal turbulence.

Top 10 Most Turbulent Routes in Africa. Photo: GC Map

Cape Town (CPT) to Johannesburg (JNB) is another turbulence-prone route, influenced by the varying topographical features of South Africa, including the highveld and the influence of the Drakensberg Mountains. The interaction between these geographical features and the changing weather patterns results in frequent and sometimes severe turbulence. Similarly, the shorter route from Durban (DUR) to JNB experiences turbulence due to the high-altitude changes and the influence of the surrounding highlands.

The combination of mountain ranges, coastal influences, and desert landscapes requires advanced forecasting and careful route planning. Understanding these factors is crucial for ensuring safe and comfortable flights across the continent.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :-------------------------------------- | :------------ | :-------------------- | | 1 | Cape Town (CPT) - Durban (DUR) | 1278 | 14.894 | | 2 | Cape Town (CPT) - Mpaka (SHO) | 1516 | 14.633 | | 3 | Cape Town (CPT) - Maputo (MPM) | 1614 | 14.582 | | 4 | Cape Town (CPT) - Johannesburg (JNB) | 1270 | 14.203 | | 5 | Durban (DUR) - Johannesburg (JNB) | 478 | 14.034 |
EI-KDC Air Astana  Airbus A321Neo During Golden Hour. Photo: Alberto Cucini/Airways

Most Turbulent Short-Range Routes

Short-range routes, typically covering distances up to 1,500 kilometers, often experience turbulence due to rapid changes in weather and terrain over relatively short distances. These routes can be particularly challenging because pilots have less time to adjust to turbulent conditions, making the flights more susceptible to sudden and severe turbulence.

Among these, the Almaty (ALA) to Bishkek (FRU) route stands out with an average EDR of 17.457. This route's high turbulence level is primarily due to the mountainous terrain of the Tien Shan range. The close proximity of the two cities and the rapid altitude changes contribute significantly to the turbulent conditions experienced. 

Another notable short-range route is from Lanzhou (LHW) to Chengdu (CTU) in central China, which is influenced by the complex topography and varying climatic conditions, including the effects of the Tibetan Plateau and seasonal monsoon winds. This combination of geographic and atmospheric factors results in frequent and intense turbulence.

Top 10 Most Turbulent Short-Range Routes. Photo: GC Map

Routes within Japan, such as Centrair (NGO) to Sendai (SDJ) and Osaka (KIX) to SDJ, also exhibit high turbulence levels. The turbulence on these routes is largely due to Japan's mountainous terrain and the proximity to the Pacific Ocean, which can cause strong wind currents and sudden weather changes. 

The influence of the coastal winds and the rugged interior of Japan make these short flights particularly challenging. Additionally, European routes like Milan (MXP) to Geneva (GVA) and MXP to Zurich (ZRH) frequently experience turbulence due to the Alps. The wind patterns interacting with the high peaks of the Alps result in significant mountain wave turbulence, causing consistent turbulence along these flight paths.

Central China's routes, such as Lanzhou (LHW) to Xianyang (XIY) and XIY to Chengdu (CTU), face turbulence driven by the region's diverse terrain and complex weather patterns. The Sichuan Basin and surrounding highlands contribute to atmospheric instability, leading to frequent turbulent episodes. 

Furthermore, the Wuhan (WUH) to Xianyang (XIY) route showcases how central China's topography and varying climatic conditions result in high turbulence levels. These routes demonstrate how short-range flights can face diverse and persistent turbulence due to a mix of geographical features and weather patterns, requiring pilots to be particularly vigilant and well-prepared for sudden turbulence.

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :---------------------------------- | :------------ | :-------------------- | | 1 | Almaty (ALA) - Bishkek (FRU) | 210 | 17.457 | | 2 | Lanzhou (LHW) - Chengdu (CTU) | 661 | 16.75 | | 3 | Centrair (NGO) - Sendai (SDJ) | 517 | 16.579 | | 4 | Milan (MXP) - Geneva (GVA) | 214 | 16.398 | | 5 | Lanzhou (LHW) - Xianyang (XIY) | 519 | 16.337 | | 6 | Osaka (KIX) - Sendai (SDJ) | 655 | 16.307 | | 7 | Xianyang (XIY) - Chengdu (CTU) | 624 | 16.25 | | 8 | Xianyang (XIY) - Chongqing (CKG) | 561 | 16.041 | | 9 | Milan (MXP) - Zurich (ZRH) | 203 | 16.016 | | 10 | Wuhan (WUH) - Xianyang (XIY) | 654 | 16.008 |
B-20C6 China Southern Airlines Boeing 787-9 Dreamliner. Photo: Davide Calabresi/Airways

Most Turbulent Medium-Range Routes

Medium-range routes, covering distances between 1,500 and 4,500 kilometers, often encounter a variety of terrains and weather systems, resulting in sustained periods of turbulence. The Santiago (SCL) to Santa Cruz (VVI) route stands out as the most turbulent one, with an average EDR of 17.568. This high turbulence level is primarily due to the Andes mountains, which create significant wind shear and mountain wave turbulence as Pacific and Atlantic winds intersect. 

Similarly, the route from Qingdao (TAO) to Kathmandu (KTM) and other Kathmandu-centric routes highlight the impact of the Himalayas. The mountainous terrain and complex weather patterns, including monsoons and jet streams, significantly contribute to the turbulence experienced on these flights. In this category, Nepal’s Kathmandu Airport (KTM) featured the most, with six routes either departing from or arriving at the city, highlighting its challenging terrain and weather conditions. 

Top 10 Most Turbulent Medium-Range Routes. Photo: GC Map

Routes such as Seoul (ICN) to KTM and KTM to Chengdu (TFU) exhibit high turbulence due to the combined effects of high-altitude mountain ranges and fluctuating weather systems. The presence of jet streams and frequent atmospheric disturbances make these routes challenging. In South America, the route from Florianópolis (FLN) to Santiago (SCL) shows significant turbulence due to the Andes and varying climatic conditions along the route. These factors create consistent, high-intensity turbulence that demands careful navigation and preparedness.

Moreover, in China, routes like Lanzhou (LHW) to Nanjing (NKG) and LHW to Hangzhou (HGH) encounter turbulence influenced by the complex topography and dynamic weather conditions in central China. The Sichuan Basin and surrounding highlands contribute to atmospheric instability, leading to frequent turbulences. 

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :---------------------------------- | :------------ | :-------------------- | | 1 | Santiago (SCL) - Santa Cruz (VVI) | 1905 | 17.568 | | 2 | Qingdao (TAO) - Kathmandu (KTM) | 3397 | 15.816 | | 3 | Kathmandu (KTM) - Chengdu (TFU) | 1879 | 15.706 | | 4 | Seoul (ICN) - Kathmandu (KTM) | 3973 | 15.502 | | 5 | Kathmandu (KTM) - Beijing (PKX) | 3144 | 15.501 | | 6 | Kathmandu (KTM) - Shanghai (PVG) | 3541 | 15.465 | | 7 | Kathmandu (KTM) - Chongqing (CKG) | 2089 | 15.406 | | 8 | Lanzhou (LHW) - Nanjing (NKG) | 1500 | 15.345 | | 9 | Florianópolis (FLN) - Santiago (SCL) | 2220 | 15.307 | | 10 | Lanzhou (LHW) - Hangzhou (HGH) | 1708 | 15.281 |
9N-ALY Nepal Airlines Airbus A330-200. Photo: Airbus

Most Turbulent Long-Range Routes

Long-range routes, extending over 4,500 kilometers, face prolonged exposure to various atmospheric conditions, making them susceptible to extended periods of turbulence. The route from Tokyo (NRT) to Kathmandu (KTM) is noted for its high turbulence, with an average EDR of 15.531. This turbulence is influenced by the extensive flight path over diverse terrains, including the mountainous regions of Japan and the Himalayas, as well as variable weather systems like monsoons and jet streams. 

Tokyo routes frequently appear in this category due to their long flight paths over both continental and oceanic areas, which can bring a variety of turbulent conditions. Routes from Tokyo to major South Asian cities like New Delhi (DEL) and Dhaka (DAC) also face high turbulence levels. These flights traverse significant atmospheric disturbances, including the impact of the Himalayas and the seasonal monsoon patterns. 

Top 10 Most Turbulent Long-Range Routes. Photo: GC Map

Additionally, routes from Seoul (ICN) to DEL and NRT to Mumbai (BOM) are notable for frequent yet short turbulences, driven by similar factors of complex topography and dynamic weather systems over long distances. Other long-range routes, such as Cape Town (CPT) to São Paulo (GRU), experience turbulence due to the interaction of oceanic and continental weather systems. 

The extensive over-water segments, combined with the influence of the Southern Hemisphere's weather patterns, contribute to the turbulence among long-haul routes. Similarly, routes from the Middle East to East Asia, such as Abu Dhabi (AUH) to Shanghai (PVG) and Dubai (DXB) to PVG, face turbulence due to the combination of desert climates, jet streams, and coastal weather systems over extended flight durations. 

| Rank | Route | Distance (km) | Avg. turbulence (edr) | | :--- | :---------------------------------- | :------------ | :-------------------- | | 1 | Tokyo (NRT) - Kathmandu (KTM) | 5223 | 15.531 | | 2 | Tokyo (HND) - New Delhi (DEL) | 5872 | 14.838 | | 3 | Tokyo (NRT) - Dhaka (DAC) | 4954 | 14.798 | | 4 | Seoul (ICN) - New Delhi (DEL) | 4662 | 14.696 | | 5 | Tokyo (NRT) - Mumbai (BOM) | 6795 | 14.626 | | 6 | Cape Town (CPT) - São Paulo (GRU) | 6361 | 14.465 | | 7 | Abu Dhabi (AUH) - Shanghai (PVG) | 6560 | 14.352 | | 8 | Dubai (DXB) - Shanghai (PVG) | 6459 | 14.343 | | 9 | Dubai (DXB) - Wuhan (WUH) | 5755 | 14.33 | | 10 | Doha (DOH) - Hangzhou (HGH) | 6703 | 14.171 |
A6-EOD Airbus A380-800. Photo: Luca Flores/Airways

Conclusion

Understanding and managing turbulence is crucial for ensuring the safety and comfort of air travel. The routes discussed above highlight the diverse and challenging conditions that can affect flights worldwide. From the mountain-induced turbulence of the Andes and Alps to the oceanic influences in Oceania, each region presents unique challenges for pilots and passengers. 

As aviation technology and meteorological science continue to advance, the ability to predict and mitigate turbulence is improving, offering hope for smoother flights even on the most turbulent routes. 

The commitment to safety and comfort in aviation necessitates ongoing research and development in turbulence forecasting and management. Airlines and meteorological organizations must continue to collaborate closely to enhance turbulence prediction models and develop better strategies for handling turbulent conditions.

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