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Severe Turbulence

Severe turbulence is the level where aircraft briefly lose control, passengers feel strong upward and downward forces, and walking is impossible. Here's everything you need to know — which routes get it, when it's worst, and how to prepare.

What causes severe turbulence?

Severe turbulence (EDR 0.4–0.7 m²/³s⁻¹) is caused by three main phenomena: (1) Jet stream wind shear — violent boundary between fast-moving jet stream air and calmer air below creates severe CAT with no visual warning, (2) Mountain wave turbulence — extreme waves extending to cruise altitude downwind of mountain ranges like the Andes, Rockies, and Alps, (3) Convective turbulence — cumulonimbus storm cells generating extreme up- and downdrafts. The first two are most relevant to commercial flights; pilots route around thunderstorms when possible.

Which months have most severe turbulence?

Northern Hemisphere winter (December–March): jet stream is at its strongest (150–200 mph), producing the most severe CAT over the Atlantic and Pacific. Spring (March–May): transition season with strong frontal systems. Southern Hemisphere winter (June–August): severe Andes crossing turbulence peaks. Typhoon season (June–November) brings severe convective turbulence in the western Pacific. Summer over the North Atlantic is generally the calmest.

Most Turbulent Routes

Ranked by historical turbulence score — click any route for details

SCL → MDZ
Santiago → Mendoza
Heavy
MDZ → SCL
Mendoza → Santiago
Heavy
DEN → JAC
Denver → Jackson Hole
Heavy
JAC → DEN
Jackson Hole → Denver
Heavy
EZE → SCL
Buenos Aires → Santiago
Heavy
JAC → SLC
Jackson Hole → Salt Lake City
Heavy
SCL → EZE
Santiago → Buenos Aires
Heavy
SLC → JAC
Salt Lake City → Jackson Hole
Heavy
ASE → DEN
Aspen → Denver
Heavy
DEN → ASE
Denver → Aspen
Heavy
EGE → DEN
Vail → Denver
Moderate
DEN → EGE
Denver → Vail
Moderate Browse all routes →

Frequently Asked Questions

How do I know if my flight will have severe turbulence?
Check TurboTrack 24–48 hours before your flight. The app shows route-specific turbulence scores plus current SIGMETs (official severe turbulence warnings). Flights on routes scoring 8+ have a high probability of moderate-to-severe turbulence. Active SIGMETs along your route indicate documented severe areas. You can also check aviation weather sites for turbulence AIRMETs (moderate) and SIGMETs (severe).
What routes get severe turbulence most often?
Most frequent severe turbulence: (1) SCL–MDZ (Santiago–Mendoza) — world's worst, Andes crossings, (2) Any DEN/SLC/BZN departure or arrival over the Rockies, (3) Transatlantic routes in winter (JFK–LHR, BOS–LHR), (4) LAX–NRT or ORD–NRT transpacific in winter, (5) Alpine routes MXP–GVA, MXP–ZRH. All are normal, regularly-flown routes — severe turbulence means uncomfortable, not dangerous.
What should I do if severe turbulence hits?
If severe turbulence occurs: (1) Fasten seatbelt immediately and tighten it, (2) If standing, sit in the nearest seat and buckle up, (3) Hold armrests, not the tray table, (4) Do not attempt to move through the cabin, (5) Protect your head if you feel yourself rising. The most important preparation is wearing your seatbelt at all times when seated — severe turbulence often starts without warning.
Is severe turbulence the same as extreme turbulence?
No. Severe turbulence (EDR 0.4–0.7) causes large altitude deviations and loss of directional control but the aircraft returns to controlled flight. Extreme turbulence (EDR > 0.7) is violent and the aircraft may be structurally stressed — though still within limits. Extreme turbulence is very rare on commercial flights, affecting perhaps 1 in 10,000 flights. Severe turbulence affects roughly 1 in 500 flights.
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