50 Fun Facts About Thunderstorms

Thunderstorms occur in which type of cloud?

The towering clouds can reach heights of more than 20 kilometres.

What is the first phase of a thunderstorm's life cycle called?

Moisture is lifted by thermals, converging winds or rising terrain and condenses into towering cumulus.

What gives a mature thunderstorm cloud its characteristic anvil shape?

The resulting cloud is called cumulonimbus incus.

What marks the mature stage of a thunderstorm?

Turbulence at this stage brings strong winds, severe lightning and even tornadoes.

How long does a typical single-cell thunderstorm last?

Without wind shear the downdraft cuts off the inflow and the storm 'rains itself out'.

What atmospheric ingredient allows a storm to become a long-lived supercell?

Shear separates the downdraft from the updraft so the mature stage can sustain itself for hours.

What is the rotating updraft inside a supercell called?

Supercells can be 24 kilometres wide and their anvils can punch into the stratosphere.

What proportion of supercells produce severe weather, according to research?

Most tornadoes come from this type of storm.

Which is the most common type of thunderstorm development?

Each cell may last 20 minutes but the cluster can persist for hours.

A squall line that bulges outward on radar is called what?

The bulging section is where strong straight-line winds are most likely.

What name is given to fast-moving summer bow echoes that race across large areas?

The word is Spanish for 'straight', for the straight-line winds they bring.

In the US, a thunderstorm is classed as severe if its winds reach at least what speed?

Hail of 25 mm or more, or a reported funnel cloud, also qualifies.

Mesoscale convective systems bring the US Great Plains roughly what share of their warm-season rain?

Most of these storm complexes form overnight and last into the next day.

What colour tint sometimes signals a thundercloud capable of producing hail?

Hail is also commoner along mountain ranges, where orographic lifting strengthens updrafts.

Which city is North America's most hail-prone, with nine to ten hailstorms a season?

It sits in 'Hail Alley', where Colorado, Nebraska and Wyoming meet.

The largest US hailstone by circumference and length fell in 2003 in which state?

It came down at Aurora.

Hail can seriously damage aircraft within seconds once stones exceed what diameter?

Wheat, corn, soybeans and tobacco are the crops most sensitive to hail.

Which European country is singled out for its frequent hail?

Mountainous northern India, meanwhile, recorded one of history's deadliest hailstorms in 1888.

What is the strongest category on the Enhanced Fujita tornado scale?

An EF5 rips buildings from their foundations; the TORRO scale runs to T11.

How wide is a typical tornado?

Most have winds of 40 to 110 mph and travel a few kilometres before dying.

What is a waterspout, technically?

Most are non-supercell tornadoes and are commonest in the tropics.

What happens when a thunderstorm's downdraft hits the ground and spreads out?

The sudden shift in wind speed and direction is a serious danger to aircraft.

What triggers the medical phenomenon known as 'thunderstorm asthma'?

Pollen grains absorb moisture, burst into tiny pieces and slip past the nose's filters into the lungs.

Roughly how many thunderstorms are occurring on Earth at any given moment?

They can happen even in polar regions, but tropical rainforests see them almost daily.

Which two Ugandan places have been called the most thunderous on Earth?

Singapore and Bogor on Java make the same claim.

In summer, air-mass thunderstorms are an almost daily occurrence in which US state?

The West Coast, by contrast, sees relatively few thunderstorms.

The energy released by a typical thunderstorm is compared to what?

Around 500 million kilograms of water vapour condense, releasing about a thousand trillion joules.

What exotic particles has NASA's Fermi observatory detected being produced in thunderstorms?

They form in terrestrial gamma-ray flashes, of which about 500 may occur daily.

Which field research project used 'Doppler on Wheels' radar trucks to study tornadic storms?

Storm chasers head to the Great Plains and Canadian Prairies every spring.

Which Norse god's hammer blows were believed to cause thunder and lightning?

The Greeks blamed Zeus, and some Native American tribes the Thunderbird.

Which Hindu god is recognised as the god of rain and thunderstorms?

Such beliefs remained mainstream as late as the 18th century.

Which religious reformer vowed to become a monk after being caught in a thunderstorm?

He prayed to be saved and kept the promise.

Lightning on which planet can be up to a thousand times more powerful than on Earth?

Its storms are tied to water clouds and driven by heat rising from the interior.

To roughly what temperature does the air around a lightning flash heat?

That is around five times hotter than the surface of the Sun.

How often does lightning strike somewhere on Earth, on average?

That works out at nearly 1.4 billion flashes a year.

What tubular structures form when lightning melts sandy soil?

The soil around the plasma channel fuses into glassy tubes.

Counting seconds between flash and thunder, roughly how many seconds equal one kilometre of distance?

The rule works because light arrives almost instantly and sound travels about 340 metres a second.

How many times a year does lightning strike the Empire State Building, on average?

Tall structures make ideal paths for cloud-to-ground strokes.

Over which Venezuelan body of water does the 'everlasting storm' of Catatumbo lightning occur?

It flashes 16 to 40 times a minute for up to 160 nights a year, the densest lightning on Earth.

Park ranger Roy Sullivan holds the record for surviving how many lightning strikes?

The 'Human Lightning Rod' was hit between 1942 and 1977 in Shenandoah National Park.

Red sprites are electrical discharges that occur where?

They are usually set off by positive lightning between cloud and ground.

Who erected the first proper grounded lightning rod, in 1754?

The Czech priest beat Franklin's practical rods, though Franklin had speculated about them for years.

Which lightning god belongs to Aztec mythology?

Perun is Slavic, Raijin Shinto and Ukko Finnish.

What is the diameter of an average thunderstorm?

Each of its three life stages lasts roughly 30 minutes on average.

In the early 20th century, 'squall line' was used as a synonym for which weather feature?

Today it means an elongated line of severe storms that can form along or ahead of a cold front.

A 'training' thunderstorm, where new cells keep forming upwind, caused a deadly 1972 flash flood where in South Dakota?

Boscastle in England in 2004 and Chennai in 2015 suffered similar back-building flash floods.

Why is hail more common along mountain ranges?

Stronger updrafts keep stones aloft longer, letting them grow.

Roughly what is the pH of 'clean', unpolluted rain?

Carbon dioxide forms weak carbonic acid, and thunderstorm nitric oxide can push rain more acidic still.

One of the earliest recorded deadly hailstorms, around the 9th century, struck which Himalayan site?

Northern India also reported one of history's highest hail death tolls in 1888.

Which three US states meet in the region nicknamed 'Hail Alley'?

Most of its hail falls in afternoons and evenings between May and September.