ROCKTUCATION
Rocktoids.
Every daily fact, kept forever.
Rocktoids · 76 facts and counting
The rock's collection of true weather facts, each one checked before it was allowed in. One appears on the forecast page daily; the whole shelf lives here.
Rocktoid No. 1
Lightning is about five times hotter than the surface of the sun.
A lightning bolt heats the air around it to roughly 50,000 degrees Fahrenheit. The surface of the sun runs closer to 10,000. The air gets so hot so fast that it explodes outward, and that shockwave is the thunder you hear. The rock has opinions about standing outside during this.
Rocktoid No. 2
Raindrops are not teardrop shaped. They look like tiny hamburger buns.
The classic teardrop shape is a myth. Small raindrops are almost perfect spheres, and bigger ones flatten on the bottom as they fall through the air, ending up shaped like a hamburger bun. When they get too big, air resistance splits them into smaller drops and the whole thing starts over.
Rocktoid No. 3
Snow is not white. Snowflakes are actually clear.
Individual snow crystals are transparent, like tiny panes of glass. Snow looks white because all those clear crystals bounce light around in every direction until every color mixes back together. Same reason a pile of crushed clear ice looks white. The rock finds this deeply suspicious.
Rocktoid No. 4
A puffy summer cloud can weigh more than a million pounds.
An average cumulus cloud holds around 500 million grams of water, which works out to about 1.1 million pounds hanging over your head. It floats because that weight is spread across a huge volume of air in droplets too small to fall. Basically a lake in the sky, politely staying up there.
Rocktoid No. 5
The smell of rain has a name: petrichor.
That earthy smell right when rain starts is called petrichor. A big part of it is geosmin, a compound made by soil bacteria that gets kicked into the air when raindrops hit dry ground. Human noses are absurdly good at detecting geosmin, down to a few parts per trillion. You were built to smell rain coming.
Rocktoid No. 6
Count the seconds between lightning and thunder, divide by five, and that is the miles away.
Light reaches you almost instantly, but sound crawls along at about a mile every five seconds. So flash-to-boom in ten seconds means the strike was about two miles off. If the flash and the boom show up together, the storm is on top of you and the rock recommends being somewhere else.
Rocktoid No. 7
The fastest wind gust ever recorded was 253 miles per hour.
During Cyclone Olivia in 1996, a weather station on Barrow Island, Australia clocked a gust at 253 mph, the fastest surface wind ever officially recorded outside a tornado. The old record, 231 mph on New Hampshire's Mount Washington in 1934, stood for 62 years and is still the fastest ever measured by a person on site.
Rocktoid No. 8
The hottest air temperature ever officially recorded is 134 degrees, in Death Valley.
Furnace Creek in Death Valley, California hit 134 degrees Fahrenheit on July 10, 1913, still the official world record. Some weather historians argue about that reading, but Death Valley keeps backing itself up: it has hit 130 in modern times too. The rock would be doing a lot of sweating.
Rocktoid No. 9
The coldest temperature ever recorded on Earth was 128.6 degrees below zero.
Vostok Station in Antarctica logged minus 128.6 degrees Fahrenheit on July 21, 1983, the coldest air temperature ever measured at ground level. At that temperature, steel can shatter like glass and boiling water thrown into the air freezes before it lands. Full ice cube mode.
Rocktoid No. 10
The largest hailstone ever found in the US was eight inches across.
On July 23, 2010, a hailstone eight inches in diameter, nearly two pounds, fell on Vivian, South Dakota. That is bigger than a softball. It left a crater in the ground. The homeowner kept it in his freezer. Hail that size falls at highway speeds, which is why the rock respects hail.
Rocktoid No. 11
It really can rain fish and frogs.
Waterspouts and strong updrafts can pull small fish and frogs out of ponds and shallow water, carry them for miles, and drop them on very confused towns. It has been documented all over the world for centuries. Honduras even has a town famous for reports of it happening again and again.
Rocktoid No. 12
Sometimes the wind makes its own snowballs. They are called snow rollers.
When the snow is sticky, the ground is icy, and the wind is just right, gusts will peel up a layer of snow and roll it along like a cinnamon roll. Fields end up dotted with hollow snow doughnuts that nobody made. The conditions have to be so perfect that many people never see one in their life.
Rocktoid No. 13
Some rain never reaches the ground. It is called virga.
Virga is rain that falls from a cloud and evaporates mid-air before it lands, leaving gray streaks hanging under the cloud like jellyfish tentacles. It is common over deserts, where the air near the ground is too dry for the rain to survive the trip. Rain with commitment issues.
Rocktoid No. 14
Antarctica is technically a desert. The biggest one on Earth.
A desert is defined by how little precipitation falls, not by heat, and much of Antarctica's interior gets only a couple inches of snow a year. That makes it the largest desert on the planet, bigger than the Sahara. Parts of its Dry Valleys are among the driest places on Earth.
Rocktoid No. 15
Parts of Chile's Atacama Desert have gone decades without measurable rain.
The Atacama sits in a double rain shadow between two mountain ranges, and some of its weather stations have recorded decades with essentially no rainfall at all. It is so dry that scientists use it as a stand-in for Mars. When rain finally does come, the desert briefly explodes with flowers.
Rocktoid No. 16
What you hear on a windy day is not the wind. Wind is silent.
Moving air on its own makes almost no sound. The howling and whistling is the sound of wind colliding with things: trees, wires, corners of your house, the gap under a door. Different obstacles make different notes, which is why every windy night sounds a little different. The rock hears everything and says nothing.
Rocktoid No. 17
Every rainbow is a full circle. The ground just gets in the way.
A rainbow is a circle of light centered on the point exactly opposite the sun from your eyes. From the ground you only see the top arc because the earth cuts off the rest. From an airplane, with the sun behind you, you can sometimes see the entire ring floating on the clouds.
Rocktoid No. 18
Identical twin snowflakes have actually been found.
The old line says no two snowflakes are alike, and statistically that is nearly true for big, complicated flakes. But in 1988 a scientist named Nancy Knight, flying through clouds for research, found two simple hollow-column snow crystals that were, for all practical purposes, identical. The rock loves a technicality.
Rocktoid No. 19
The US gets more tornadoes than any other country. Over a thousand a year.
Flat terrain, warm Gulf moisture, and cold dry air rolling off the Rockies make the American middle the most tornado-prone real estate on Earth, averaging more than 1,200 twisters a year. No other country comes close. The rock has never once considered living in a trailer park.
Rocktoid No. 20
The rainiest place on Earth gets about 470 inches of rain a year.
Mawsynram, a village in the hills of northeastern India, averages roughly 467 inches of rain annually, most of it during monsoon season. That is nearly 39 feet of water. Locals weave full-body bamboo umbrellas called knups so they can work outside in it. The rock would simply dissolve.
Rocktoid No. 21
On brutally cold days, the air itself can sparkle. That is called diamond dust.
When it is cold enough, moisture in the air freezes into tiny ice crystals that hang there glittering in the sunlight, even under a clear blue sky. It is called diamond dust, and it can make halos and light pillars around the sun. One of the few perks of minus 20.
Rocktoid No. 22
Crickets are tiny thermometers. Count their chirps and you get the temperature.
Crickets chirp faster in warm air, so reliably that there is a formula called Dolbear's law: count the chirps in 14 seconds, add 40, and you get a rough temperature in Fahrenheit. The rock considers this showing off, but admits the crickets are usually right.
Rocktoid No. 23
Scientists think it rains diamonds on Neptune.
Deep inside Neptune and Uranus, the pressure is so extreme that scientists believe carbon squeezes into actual diamonds that sink toward the core like hail. Lab experiments have recreated the process. Somewhere out there is weather worth standing in, and the rock wants a transfer.
Rocktoid No. 24
Lightning hits our planet about 8 million times a day.
Earth runs about 100 lightning strikes every single second, roughly 8 million a day, most of them in the tropics. One spot on Lake Maracaibo in Venezuela gets storms so reliably that sailors once used the lightning as a natural lighthouse. The rock stays grounded, in every sense.
Rocktoid No. 25
There is such a thing as a moonbow: a rainbow made of moonlight.
Bright moonlight hitting rain or waterfall mist can make a rainbow at night. Moonbows are faint, so to your eye they usually look ghostly white, but a camera on a long exposure reveals the full colors. Your best odds are near big waterfalls under a full moon.
Rocktoid No. 26
Heat lightning is not a special kind of lightning. It is just a storm too far away to hear.
Those silent flashes on a warm summer night are ordinary lightning from a storm 10 or more miles away. You can see the flash over the horizon, but thunder rarely survives more than about 10 miles of air. The storm is real, it is just somebody else's problem. The rock's favorite kind of storm.
Rocktoid No. 27
Weather rocks like this one have hung outside ranger stations for generations.
The weather rock is a classic piece of American folk humor: a rock on a string with a sign reading, if the rock is wet, it is raining. If it is white, it is snowing. If it is gone, tornado. Versions have hung outside ranger stations, gift shops, and bait shops for generations. This site is just the first one with googly eyes and a data plan.
Rocktoid No. 28
A single thunderstorm can hold more energy than an atomic bomb.
An average thunderstorm releases energy on the scale of hundreds of Hiroshima bombs over its lifetime, mostly as heat when water vapor condenses. It just spends that energy over hours instead of a single instant. The sky is running heavy machinery up there. The rock keeps a respectful distance, which is zero, because it cannot move.
Rocktoid No. 29
Sunsets get more spectacular after volcanic eruptions, all over the world.
Big eruptions throw fine ash and sulfur particles into the upper atmosphere, where they scatter sunlight and turn sunsets vivid red and purple for months, sometimes worldwide. After Krakatoa erupted in 1883, sunsets were so intensely red that fire departments in some cities were called out for fires that were not there.
Rocktoid No. 30
Your morning frost can grow fur. It is called hoar frost.
On calm, cold, humid nights, water vapor skips the liquid step and freezes straight onto branches, fences, and spiderwebs as feathery ice crystals called hoar frost. A heavy coating turns the whole world fuzzy and white by sunrise, then usually vanishes within an hour of daylight. Get out early or miss it.
Rocktoid No. 31
Wildfires can create their own weather, including tornadoes of flame.
A fire big enough generates its own updraft, forming pyrocumulus clouds that can produce lightning and start further fires. In extreme cases rotating columns of flame called fire whirls form, some exceeding a hundred feet.
Rocktoid No. 32
A bolt of lightning carries enough energy to toast about 100,000 slices of bread.
A typical strike releases around five billion joules. The catch is that it delivers all of it in a few ten-thousandths of a second, which is why lightning cannot practically be harvested. Far too much energy arriving far too quickly.
Rocktoid No. 33
An average cumulus cloud weighs about as much as a hundred elephants.
A typical fair-weather cumulus holds around a million pounds of water. It stays up because that water is spread across an enormous volume as tiny droplets, and the air beneath is denser than the cloud as a whole.
Rocktoid No. 34
Hot water can freeze faster than cold water.
It is called the Mpemba effect, observed since Aristotle and still not fully explained. Evaporation, dissolved gases and convection currents all seem to play a part. Under the right conditions the hot pan really does beat the cold one.
Rocktoid No. 35
Snow is not white. Ice is clear.
Snow looks white because a snowflake's many surfaces and air pockets scatter every wavelength of visible light back at you at once. Deep snow can look blue for the same reason deep water does, absorbing red light before blue.
Rocktoid No. 36
Antarctica has a river that runs blood red.
Blood Falls in the Taylor Glacier is fed by a brine trapped under the ice for over a million years. It is rich in iron, which rusts on contact with air. There are microbes living in that brine with no sunlight and no oxygen.
Rocktoid No. 37
It has rained fish, frogs, and once, golf balls.
Waterspouts and strong updrafts lift small animals out of shallow water, carry them for miles, and drop them when the wind gives up. Honduras gets it often enough to have a festival for it. Punta Gorda, Florida got golf balls in 1969, presumably from a flooded course. The rock has never fallen from the sky and intends to keep that record intact.
Rocktoid No. 38
Lightning hits the Earth about 100 times every second.
Around eight million strikes a day worldwide. Most happen over land in the tropics, and almost none over the poles. While you read this sentence, roughly three hundred bolts landed somewhere. While you read that sentence, roughly three hundred bolts landed somewhere. None on me. So far.
Rocktoid No. 39
There is a place where lightning strikes almost every night of the year.
Over Lake Maracaibo in Venezuela, warm air off the lake meets cold air off the Andes and produces the Catatumbo lightning: up to 300 storm nights a year, 28 strikes a minute at peak. Sailors used it as a lighthouse. The rock would simply move.
Rocktoid No. 40
Nature makes its own snowballs, and they are hollow.
Snow rollers form when wind pushes a clump of wet snow across a crust it will not stick to, rolling it into a cylinder. The fragile middle usually collapses, leaving a natural donut. They need such precise conditions that most people never see one. The rock has seen four and is unbearable about it.
Rocktoid No. 41
Antarctica is a desert.
A desert is defined by precipitation, not temperature. Much of Antarctica gets under two inches a year, drier than the Sahara. The ice is old, not new. Some valleys there have not seen rain in two million years. The rock finds that a bit much, even for him.
Rocktoid No. 42
A hurricane releases more energy in a day than the entire world uses in a year.
Most of it goes into forming clouds and rain rather than wind. The heat released by condensation in a mature hurricane is estimated at 200 times the world's total electrical generating capacity. The rock's contribution to the world's energy budget is sitting still, which he considers underrated.
Rocktoid No. 43
Rain that never reaches the ground has a name: virga.
Those grey streaks hanging under a cloud that seem to stop in mid-air are real rain evaporating on the way down. In deserts it happens constantly. It is the sky trying to rain on you and giving up halfway. The rock relates to this deeply.
Rocktoid No. 44
A snowflake fell in Montana that was reportedly 15 inches across.
Fort Keogh, 1887. A rancher described flakes larger than milk pans. Meteorologists suspect several flakes clumped together on the way down. It remains the largest snowflake ever claimed, and the rock suspects nobody was measuring very carefully.
Rocktoid No. 45
Groundhog Day is right about 39 percent of the time.
You would do better flipping a coin. Studies comparing Punxsutawney Phil's predictions against actual spring temperatures put him below chance. He has been doing this since 1887 and his record has not improved.
Rocktoid No. 46
Some clouds look like a sky full of hanging bags.
Mammatus clouds form when cold air sinks in pouches beneath a storm anvil, creating rows of drooping lobes. They usually appear after the worst has passed, which makes them the sky's most ominous-looking all-clear.
Rocktoid No. 47
Sand from the Sahara fertilises the Amazon rainforest.
Around 27 million tons of dust cross the Atlantic every year. It carries phosphorus from an ancient dried lake bed in Chad, replacing exactly what the rainforest loses to its own rain. Two continents, one nutrient cycle.
Rocktoid No. 48
Lightning turns sand into glass tubes.
When a bolt hits sandy ground it can heat the sand past 3,000 degrees and fuse it into a hollow branching tube called a fulgurite, tracing the exact path the electricity took underground. People dig them up as sculptures.
Rocktoid No. 49
There was a year without a summer.
In 1816, ash from the Tambora eruption cooled the northern hemisphere so much that New England had snow in June and crops failed across Europe. The gloom kept a group of holidaymakers indoors in Switzerland, where one of them wrote Frankenstein.
Rocktoid No. 50
Thunder can happen during a snowstorm. It is called thundersnow.
It is rare because snowstorms usually lack the strong updrafts thunderstorms need. When it does happen the snow muffles the sound, so instead of a long rumble you get one short crack and an eerie silence.
Rocktoid No. 51
The wettest place on Earth gets about 40 feet of rain a year.
Mawsynram in northeastern India averages roughly 467 inches. Locals make ladders and bridges out of living tree roots because anything built dies in the damp, and they soundproof huts with grass so the rain does not drown out conversation.
Rocktoid No. 52
A rainbow is actually a full circle.
You only ever see an arc because the ground gets in the way. From an aeroplane, with the sun behind you and rain below, you can see the whole ring. Every rainbow is a circle you are standing at the wrong height for.
Rocktoid No. 53
There are rainbows made by moonlight.
A moonbow needs a bright full moon, rain opposite it, and a very dark sky. They look white to the naked eye because moonlight is too faint for colour vision, but a long camera exposure shows the full spectrum.
Rocktoid No. 54
Above thunderstorms, red lightning shoots upward into space.
Sprites are enormous electrical discharges that flash above storm clouds, reaching 50 miles up. They last a few thousandths of a second. Pilots reported them for decades and were not believed until one was photographed by accident in 1989.
Rocktoid No. 55
A third of people struck by lightning indoors were on the phone.
Lightning travels through wiring and plumbing. Corded phones, wired appliances and showers are all routes into a house. The advice to avoid baths during a storm is not superstition.
Rocktoid No. 56
It can be too warm to snow, but never too cold.
Snow needs moisture, and very cold air holds almost none, so heavy snow is rare in extreme cold. But ice crystals can form at any temperature below freezing. The South Pole gets snow at minus 70.
Rocktoid No. 57
Hailstones have rings inside like an onion.
A hailstone is lifted and dropped repeatedly through a storm, gaining a layer of ice each trip. Cut one open and you can count the rings to see how many times it went round. The record holder weighed nearly two pounds.
Rocktoid No. 58
Cold air makes sound travel further, which is why winter nights are eerie.
Sound bends toward cooler air. On a cold still night, sound that would normally escape upward is refracted back down to the ground, carrying much further. Distant trains at 2am are a temperature inversion, not your imagination.
Rocktoid No. 59
Two hurricanes that get too close will orbit each other.
It is called the Fujiwhara effect. Storms within about 900 miles begin circling a common point, and sometimes the larger one absorbs the smaller. Occasionally they simply dance around each other and part ways.
Rocktoid No. 60
Hurricane names get retired when a storm is bad enough.
The World Meteorological Organization strikes a name from rotation if reusing it would be insensitive. Katrina, Sandy, Maria and Andrew are all permanently gone. The lists otherwise recycle every six years.
Rocktoid No. 61
Frost can grow flowers.
Frost flowers form on thin new ice when moist air freezes into delicate crystal blooms, sometimes an inch across. A different kind grows from plant stems when sap freezes and splits the stalk, extruding ribbons of ice.
Rocktoid No. 62
On very cold clear days it can snow out of a blue sky.
Diamond dust is ice crystals forming directly out of humid air near the ground with no cloud involved. It glitters in sunlight and can produce halos and sun pillars. It is snow without a snowstorm.
Rocktoid No. 63
Australia has a cloud that surfers of the sky travel to ride.
The Morning Glory is a roll cloud up to 600 miles long that appears over the Gulf of Carpentaria each spring. Glider pilots fly from around the world to soar along its leading edge, riding the wave of rising air.
Rocktoid No. 64
The Beaufort wind scale originally described what sails to use.
Admiral Beaufort wrote it in 1805 for the Royal Navy: force 5 meant a ship could carry so much canvas, force 10 meant considerably less. It was rewritten for land later. Force 12 was the point at which no canvas could stand.
Rocktoid No. 65
The smell before a thunderstorm is ozone, blown down from above.
Lightning splits oxygen molecules that recombine as ozone. Downdrafts carry it to ground level ahead of the rain, which is why you can smell a storm coming before you can see it. The sweet smell afterward is petrichor, a different thing entirely.
Rocktoid No. 66
The deadliest smog in history killed thousands in five days.
The Great Smog of London in December 1952 was a temperature inversion trapping coal smoke over the city. Visibility fell to a few feet, cattle at Smithfield suffocated, and an estimated 12,000 people died. It led directly to the Clean Air Act.
Rocktoid No. 67
Fog is just a cloud that could not be bothered to rise.
Physically there is no difference. A cloud touching the ground is fog. Walk up a mountain into a cloud and you have walked into fog. The distinction is entirely about where you happen to be standing.
Rocktoid No. 68
Some rainbows are made of fire, sort of.
A circumhorizontal arc appears when sunlight passes through ice crystals in high cirrus cloud, producing a band of pure spectrum colour that looks like a rainbow on fire. It needs the sun above 58 degrees, so it is a summer thing.
Rocktoid No. 69
Raindrops never fall faster than about 20 miles per hour.
Air resistance caps them. A large drop reaches terminal velocity almost immediately and stays there. If rain fell at the speed a stone does from the same height, being outside in a shower would be genuinely dangerous.
Rocktoid No. 70
The Sahara gets snow.
Not often, but it happens. Ain Sefra in Algeria, on the desert's northern edge at 3,000 feet, has had snow several times in the last decade, once deep enough to sled on. It usually melts within a day.
Rocktoid No. 71
There is a wind that makes people irritable, and courts once took it into account.
The Foehn, the Santa Ana, the Chinook and the Sirocco are all warm dry downslope winds associated with headaches and short tempers. Some Swiss and Italian courts historically treated the Foehn as a mitigating factor.
Rocktoid No. 72
Sun dogs are false suns, and they show up in medieval paintings.
Bright patches appear either side of a low sun when hexagonal ice crystals refract its light at 22 degrees. They have been recorded as omens for centuries. A famous 1535 painting of the sky over Stockholm shows several at once.
Rocktoid No. 73
The largest hailstone ever found was the size of a volleyball.
Vivian, South Dakota, 2010. Eight inches across, nearly two pounds, and the finder lost some of it because the power was out and it partly melted before anyone could weigh it officially.
Rocktoid No. 74
Wind has a smell, and it is mostly whatever it just flew over.
Air arriving off the sea carries dimethyl sulphide from plankton, which is the smell people call 'the ocean'. Air off a field carries the same soil compounds that make petrichor. The wind is mostly reporting on where it has been.
Rocktoid No. 75
A tornado once carried a cheque 220 miles.
Debris lifted into a supercell can stay aloft for hours. Cancelled cheques, photographs and letters have been recovered hundreds of miles from tornado paths. The 220-mile record belongs to a cheque from the 1991 Kansas outbreak.
Rocktoid No. 76
Snow squalls can drop visibility to zero in under a minute.
A narrow band of intense snow and wind moves through fast, often under a bright sky either side. Highway pileups are common because drivers go from clear conditions to nothing at all with no warning.