Which is the Worst: A Thunderstorm, Tornado, or Hurricane?

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When it comes to severe weather, thunderstorms, tornadoes, and hurricanes are regarded as nature's most violent storms. But which is the worst?

Differentiating between the three can be confusing since they all contain strong winds and sometimes occur together. This side-by-side comparison will clarify all.

If you're a student, feel free to print this checklist and use it as the ultimate severe storm study guide.


DEFINITIONA storm (produced by a cumulonimbus cloud) that includes rain showers, lightning, and thunder.A violently rotating column of air that extends down from the base of a thunderstorm to the ground.A swirling low pressure system that develops over the tropics whose sustained winds have reached 74 mph or more. 
SCALELocal LocalLarge (synoptic)


  • Moisture
  • Unstable air
  • Lift
  • Ocean temperatures of 80°F (27°F) or warmer extending from the surface down to 150 ft (46 m)
  • Moisture in the lower and middle atmosphere
  • Low wind shear
  • A pre-existing disturbance
  • A distance of 300+ miles from equator
HOW THEY FORMIt all starts when the sun heats the earth's surface and warms the layer of air above it. This warmed air then rises, transferring heat to the upper levels of the atmosphere (convection). As the air travels upward, it cools, and the water vapor contained within the air condenses to form liquid cloud droplets. As air continually travels aloft in this way, the cloud grows upward in the atmosphere, eventually reaching altitudes where the temperature is below freezing. Some of the cloud droplets freeze into ice particles, while others remain "supercooled." When these collide, they pick up electric charges from one another. When enough collisions happen, the big build up of charge discharges, creating what we call lightning.When a wind near the earth's surface blows at one speed, and a wind above that blows at a much faster speed, the air between them whips around into a horizontal rotating column. If this column gets caught in the thunderstorm updraft, its winds tighten, speed up, and tilt vertically, creating a funnel cloud.Warm, moist air near the ocean's surface rises upward, cools, and condenses, forming clouds. With less air than before now at the surface, the pressure there drops. Because air tends to move from high to low pressure, moist air from surrounding areas flows inward towards the low pressure spot, creating winds. This air is soon warmed by the ocean's heat and the heat released from the process of condensation, and also rises. This process of (1) warm air rising and forming clouds and (2) surrounding air swirling in to take its place, continues on. Before long, you have a system of clouds and winds which begins to rotate (due to the Coriolis effect).



(most likely in spring, summer)
(most likely in spring, fall)
June 1 to Nov 30
(most likely mid-August to mid-October)
(most likely in afternoons, evenings)
(most likely between 3 p.m and 9 p.m.)
LOCATIONSWorldwideWorldwideWorldwide within the 7 designated basins
DURATIONSeveral minutes to over an hour.
(30 minutes on average)
Several seconds to over an hour.
(<10 minutes on average)
Several hours to 2-3 weeks.
(12 days on average)
STORM SPEEDRanges from nearly stationary to 50 mph or more.Ranges from nearly stationary to 70 mph.
(30 mph on average)
Ranges from nearly stationary to 30 mph.
(<20 mph on average)
STORM SIZE15 mi diameter on averageRanges from 10 yards to 2.6 miles wide.
(50 yds on average) 
Ranges from 100-900 miles in diameter
(300 mi diameter on average)



A thunderstorm is classified as either severe or non-severe. If it produces one or more of the following, it is considered to be severe: ​

  • Winds of 58+ mph
  • Hail 1 inch or greater in diameter
  • Tornadoes

The Enhanced Fujita Scale (EF scale) rates tornado strength based on the damages caused.

  • EF 0
  • EF 1
  • EF 2
  • EF 3
  • EF 4
  • EF 5

The Saffir-Simpson Scale classifies cyclone strength based on the intensity of sustained wind speeds.

  • Tropical Depression
  • Tropical Cyclone
  • Category 1
  • Category 2
  • Category 3
  • Category 4
  • Category 5
HAZARDSLightning, Hail, Strong winds, Flash flooding, TornadoesHigh winds, Flying debris, Large hailHigh winds, Storm surge, Inland flooding, Tornadoes  
  • Developing stage
  • Mature stage
  • Dissipating stage
  • Developing/ Organizing stage
  • Mature stage
  • Decaying/Shrinking/ 
    "Rope" stage
  • Tropical Disturbance
  • Tropical Depression
  • Tropical Storm
  • Hurricane
  • Extra-tropical cyclone