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You’ve probably heard the phrase “it’s
raining cats and dogs outside.”
And you probably also know better than to
take that literally.
But sometimes, animals do fall from the sky.
There have been rare but regular reports of
this phenomenon going all the way back to ancient Rome.
Sure,  some of the historical accounts are
probably exaggerated, but there are enough
well-documented cases in this century that
we know that animal rain is definitely a thing.
And meteorologists think they know why.
Well, mostly.
If you read Pliny the Elder’s stories of
frogs and fish falling from the heavens, you
might be understandably skeptical.
But in 2005, thousands of frogs rained down
on a small town in Serbia.
Then, in 2009, clouds of tadpoles fell in
Japan.
And in 2010, small fish that were very much
still alive pelted a town in Australia’s
Northern Territory for several days.
That was the third time that town had experienced
animal downpours since 1970.
And similar fishy weather events have been
reported from Wales, India, the Philippines,
Honduras, Sri Lanka, Ethiopia, and Mexico
in just the last twenty years.
Other places have described storms of birds.
Also spiders.
No!
The question is, where are all these animals
coming from?
And how are they getting up in the air?
In some cases, there’s a perfectly ordinary
explanation that freaked-out observers just
aren’t aware of.
When spider rain fell in Australia three years
ago, for example, of course it was Australia,
it was probably just a case of ballooning,
where spider babies use their silk to float
long distances on air currents.
It’s perfectly natural, if slightly terrifying
when the entire landscape is suddenly coated
in a thick layer of cobwebs.
And the thousands of blackbirds that fell
out of the sky in Arkansas and Louisiana in
early 2011 probably died from crashing into
things when they were startled by the fireworks
on New Year’s Eve.
It’s those other animal rain incidents—the
aquatic ones—that are much harder to explain.
In the past, people thought maybe migrating
birds were dropping their prey en masse.
No one had any idea why they might do this,
mind you.
But why else would frogs fall from the sky?
There’s no such thing as a frog with wings.
These days, most scientists and meteorologists
think these animals come from waterspouts:
tornadoes over open water, like oceans or
large lakes.
They’re most common in tropical oceans,
but they’ve been seen all over the world,
and they can form over water even when conditions
are relatively calm.
All it takes is enough warmth and humidity
for clouds to condense and touch down.
The waterspouts that form in fair weather
tend to be small, weak, and short-lived.
But sometimes, waterspouts form when land
tornadoes move out to sea.
These are less common, but they’re also
much larger and more dangerous.
Regular tornadoes have been known to carry
lightweight debris like paper as far as 320
kilometers, and heavier objects like metal
signs for 80 kilometers.
I mean, Dorothy made it all the way to Oz.
So while waterspouts aren’t usually as strong,
the idea that they might suck up things, transport
them some distance, and then drop them in
a new location does make sense.
And if they do, those things could include
small fish or frogs.
Several of the living hail events in recent
years coincided with storms and strong winds,
which also fits the waterspouts theory.
The fact that the animals are aquatic also
makes sense.
And occasional reports of animal rain in places
far from water could be explained by land-based
tornadoes or other strong updrafts instead.
The thing is, no one has actually ever seen
this happen.
It isn’t exactly easy to observe a violent
storm over water, so it could just be that
meteorologists who study waterspouts aren’t
on high alert for airborne fish.
Or, since these “amphibious rain” events
are so rare, maybe they haven’t been in
the right place at the right time.
So even though the waterspouts idea fits really
well, we haven’t been able to confirm it.
Maybe if we did, we could also explain another
mysterious detail: why they usually involve
just one animal or even one species.
It’s frogs, or fish, not a random mix of
nearby aquatic life.
Some scientists think that that’s because
objects of similar size and weight fall out
together as storm forces die down.
Others find that answer less than satisfying,
since lakes and oceans contain lots of different
animals that are fairly similarly-sized.
Another possibility is that the spouts only
pick things up when they’re densely clustered.
But until we actually see animals getting
pulled out of the water by spouts, no one
can really say what limits the storm’s catch.
So, if fish or frogs start falling from the
sky and plopping onto the sidewalk, don’t
panic — it’s probably not a sign of the
end of times.
It’s just a really weird weather phenomenon
with a perfectly reasonable scientific explanation.
Probably.
But even if it’s not raining frogs, the
science of weather is fascinating.
Which is why I wanted to test my understanding
of atmospheric pressure systems with this Brilliant quiz.
If you want to join me, Brilliant set up a
link so you can test your knowledge too.
Click on the link in the description or go
to brilliant.org/SciShowAtmospheric in a new tab.
I’m taking a quiz.
So I first got excited about meteorology when
I was in college because there was a cute
girl who was really into meteorology.
This is how my… my interest in…
It wasn’t the weather that did it.
So I’m taking my quiz here.
Is moist air more likely to exert a higher
or lower pressure than dry air of the same temperature?
Oh.
Hmm…
I would say higher would be my guess, but
now I’m guessing.
I was wrong.
Moist air is lighter than dry air.
Huh.
I guess because water is lighter than nitrogen.
That makes sense.
Once it’s… it doesn’t seem like that
would be the case.
I hadn’t thought about that, which is why,
like, clouds rise up.
Duh.
Get your act together, Hank.
One of my favorite twitter accounts is the
National Oceanic Atmospheric Administration satellite's twitter.
Very good satellite data coming out these
days.
And I love it but I feel a little bit like
I don’t actually know what’s happening
even though this is my job.
And I’m I’m going through this and realising
that I indeed need to hone my skills to be
a person who better understands what’s actually
going on.
And you can do that too at Brilliant.org . The
First 77 viewers to sign up at Brilliant.org/Scishow
will get 20% off their annual premium subscription
and you will support SciShow.
So thanks!
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