Storm science

Hurricane vs tornado

Both spin. Both kill. Everything else is different. A side-by-side comparison of Earth's two most iconic rotating storms.

Side by side

Size

Hurricane: 100-600 miles wide. Tornado: 100 feet to 2.5 miles wide.

Duration

Hurricane: 1-4 weeks. Tornado: seconds to about 3 hours.

Peak winds

Hurricane: 200 mph max. Tornado: 300+ mph max.

Pressure drop

Hurricane: 20-100 mb below normal. Tornado: 50-200 mb below normal (extreme).

Warning time

Hurricane: days. Tornado: minutes.

Formation region

Hurricane: warm tropical ocean. Tornado: continental interior.

Season

Hurricane: June-November (Atlantic). Tornado: spring peak, fall secondary.

Deaths per storm

Hurricane: highly variable, hundreds to thousands. Tornado: usually 0-10, occasionally hundreds.

How they form

Hurricanes

Fueled by warm ocean water above 80°F to depth of 150 ft. Convergence, moisture, and Coriolis force spin an organized low. Slow to intensify (days) but can be predicted 5-10 days out.

Tornadoes

Formed inside supercell thunderstorms. Warm moist air rising through cold dry air aloft creates instability. Wind shear organizes the updraft into a rotating mesocyclone. Tornado descends when the mesocyclone tightens. Forecastable minutes to an hour ahead.

The physics differ

Hurricanes conserve angular momentum around a warm-core low that spans the entire troposphere.
Tornadoes are surface-connected vortices generated by pressure differentials within a supercell.
Hurricanes weaken over land as they lose their moisture source.
Tornadoes need land's friction differentials to help them form.
A hurricane can spawn tornadoes — landfalling hurricanes often do.
A tornado cannot spawn a hurricane.

Which is deadlier?

Total: Hurricanes kill more people globally. The Bhola Cyclone (1970) alone killed ~500,000. But per storm, tornadoes have higher intensity — a violent tornado kills or maims almost everyone in its path within 100 ft.

Per year in the US: Tornadoes kill 60-100 people. Hurricanes kill 10-500+ depending on landfall count. Both are dwarfed by heat waves (5,000+ deaths from 2003 EU heat wave).

Which is scarier?

This is a matter of perspective, but the consensus among survivors of both is: hurricanes are scarier before, tornadoes are scarier during.

Hurricanes give you days to fear them. Tornadoes give you a minute of sound and then they're on you.

Where they overlap

Landfalling hurricanes can spawn dozens of tornadoes on their right-front quadrant. Hurricane Ivan (2004) produced 118 tornadoes over three days. Hurricane Frances (2004) produced 106. This is 'hurricane-spawned tornado' territory and is a distinct forecasting challenge.