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it's all around us every day it affects our mood our livelihood our very survival if we can't change it we can hardly even predict it we fear we've come a long way in understanding and controlling our planet until we think about the weather the average temperature winds and rainfall that a place experiences over a period of years make up its climate the weather is what happens on a particular day and this doesn't always fit in with the overall climatic pattern in some places one weather day is much like another in the tropics where there's not much seasonal variation you can often set your watch by the afternoon rain shower but in temperate regions weather is far more variable in a single weather day we could see everything frost and fog blue skies and winds hail snow and thunderstorms when things are this unpredictable it helps to know which way the winds blowing weathervanes have been doing the round since 48 BC in the ninth century Pope Nicholas the first decreed that all church weathervane should feature a cockerel to remind worshipers how Saint Peter denied Christ three times before the dawn weathervanes have taken some strange turns since then dawn and with it the first clues to the new weather day it's the Sun that drives our weather from the poles to the tropics but what if one morning the Sun didn't rise an Aztec myth tells that when the gods created our world it was dark and cold the youngest of the God sacrificed himself to create a Sun but it was like him weak that feeble only when powerful God's offer themselves that the Sun blazed into life but it needed constant fuel human lives the Aztecs obliged they offered tens of thousands of human sacrifices a year just to make sure the Sun rose each morning but a sunny morning isn't always a warm one cloud keeps the earth warm after dark without this blanket temperatures can plummet overnight water vapor in the air turns into millions of ice crystals and freezes onto every surface so we may wake up to a visit from Jack Frost out of a clear blue sky global warming means freak freezes are less widespread now than in the past only two hundred years ago there were ice fares in England on the frozen river Thames it's often chilling at Niagara Falls but 20 years ago it stopped in its tracks frozen solid Frost's are still capricious you can even chill out in the tropics once in a blue moon The Morning Sun takes time to break the ice its rays are low and slanting as it rises in the sky the Rays become more powerful and that power hasn't gone unnoticed virtually every society from the Japanese to the ancient Egyptians had some history of Sun worship in Hindu belief the Sun was the god Vishnu striding across the sky in three huge leagues sunrise midday and sunset you but the power of the Sun can be a mixed blessing fortunately our planet is swaddled in layers of gases which make up the atmosphere and they filter out many of the sun's most harmful rays the layer nearest of us is the troposphere and this is where the weather action is the troposphere is about eight miles thick it's the air we breathe and it's never still as the sun's rays reach down they heat up this layer of air and make it move and swirl like soup in a cauldron the troposphere is alive with movement whipped up each day by the passage of the Sun the energy powerhouse which fuels our planet it's this complex interaction of Sun and gases which gives us our weather and makes it so changeable over much of the world we've never been able to escape the weather and it's very uncertainty intrigues us just as we've always tried to predict the future we've always tried to forecast the weather we used to think it was all in the lap of the gods the ancient Greeks believed that the weather was controlled by a pantheon of gods who amuse themselves by hurling Thunderbolts and unchaining the winds on a whim Jupiter would unleash the seas and rivers the earth its people and his weather were the gods playthings gonzo no gods the Greek philosopher Aristotle was certain that careful observation could reveal patterns in the weather he invented meteorology and ever since we've been pitting our wits against the weather our most important weapon is still the one suggested by Aristotle observing what's around us is the basis of all forecasting fortunately nature provides plenty of weather signs for the sharp-eyed some plants such as the Morning Glory open up only when it's fine and dry while pinecones only open when it's damp animals seem to know more about weather forecasting than we do old wives tales tell us that cows may lie down if there's rain coming and birds fall silent before thunderstorms old wives certainly knew their onions it's a widespread belief that if onions grow thick skins or several layers of brown ones there's a hard winter coming as the weather day wears on the air begins to stir wind is simply air rushing from one place to another it's being pushed and cooled by the Sun driven activity in the troposphere error moves from areas words cold and huddled under its own weight areas of high pressure to warmer areas where it can rise and spread out areas of low pressure it was Evangelista Torricelli a pupil of Galileo who first showed that air has weight and invented a barometer to measure its pressure 17th century Italians were dedicated to discovering the weathers secrets their instruments were the forerunners of our modern meteorological equipment Wyn can be a gentle breeze sweetly plucking an Aeolian harp or it can literally pull you over this was the Greek god of the wind he gave the hero Odysseus a present of the stormy winds safely secured in a tiny leather bag but his crew were come with curiosity undid the bag and out let the storm winds battering their ship wildly off course it's easy to believe that the ancient weather gods are still testing their strength the Tacoma bridge proved no match for the unhonest winds it only managed to hang on for four months wind may not be empty-handed in the 1930s black blizzards in the American Dust Bowl blue Topsail from one state into another until the next storm blew it all back again and there's a Japanese win so destructive that we know it better as the word for a suicide warrior the kamikaze wind has curious effects on humans American studies show that playground fights double when the wind rises two four six or more and heart attacks and strokes occur more frequently as the wind rises there are winds which seem to blow no one any good the santa Hannah in California is a hot dry wind which raises temperatures dramatically and the figures for murder and suicide rise with them murderers have even claimed its effects in their defense local winds can be vital large parts of Asia depend on the seasonal monsoon to bring rain to land which otherwise would be arid all year but it's when winds get into a spin that their full power is unleashed tornadoes are formed when strong winds stream past the top of a rising column of warm air whipping it into a spiral the winds on the outside can reach 300 miles per hour like a giant vacuum cleaner the tornado lifts anything in its path it's the touchdown which causes most of the problems there's a huge fallout of debris traveling in more than a hundred miles an hour but occasionally a tornado can exercise real delicacy like lifting up a dresser full of China and setting it down again without breaking a single thing they even been known to pluck a chicken's feathers torrid along with other weather catastrophes are still known as acts of God we recognize that weather is outside our control but we still want advance information in world war ii accurate forecasting on all in a june storm helped ensure the success of the d-day invasion weather forecasts were regarded as secret weapons classified information but even this didn't stop the British from talking about the weather nowadays the clamor for forecasts is unceasing day after day we scan the media for the weather forecast but it may not tell us much short-term forecasts are usually reliable especially in places with fairly stable weather patterns accuracy is greatest for a period 12 hours ahead and quite good up to 48 hours fill them up more than a week or two in advance and it's anybody's guess it isn't for one of trying 24 hours a day our most sophisticated efforts and enormous resources go into this quest but long range forecasting still eludes us by noon in our weather day the sun's rays are at their most powerful but at least we can try to keep a cool head although normally only mad dogs and Englishmen go out in the midday Sun some of the hottest places on earth are also the driest parts of the South American Atacama Desert haven't seen a drop of rain for over 400 years rain is essential the key to all life scratch the surface of any culture and you'll find rainmakers in 1893 there was a drought in Sicily prayers and offerings were made every possible Saint petition after six dry months the villagers turned angrily on their Saints and afflicted them on ceremonies it ray during the early years of the 20th century the American Charles H Hatfield made a good living as a Rainmaker but no one has ever discovered the secret of his success by the 1960s the Chinese had moved away from traditional gods but threatened with a major drought in 1963 they turned back to the rain God tau Howie the drought broke and tau how he began to enjoy quite a revival we've tried to apply technology to rainmaking by dropping particles of silver iodide or frozen carbon dioxide into the clouds it works up to a point and only of course if the clouds are there to start with there's no new water on our planet what we have goes round and round in a cycle evaporation from lakes and seas returns as rain which finds its way into the river and back to the oceans to start all over again but of course there's a downside to rain we can get too much consistently wet places can cope mount why alley alley in Hawaii only averages eleven dry days a year so they're used to it but sudden torrential rain anywhere else causes havoc in the Bangladesh floods of 1988 three-quarters of the country was affected hundreds drowned and over five million people were left homeless floods cost more lives than any other weather catastrophe there's always water in the air even in deserts it's held as water vapor in an invisible reservoir warm air can hold much more water vapor than cold that's why arriving in the tropics can feel like stepping into a steam room but we can't see this airborne moisture until the air cools enough for the vapor to condense into droplets like fall rain starved regions rely on this daily dose of moisture in Chile people literally net their drinking water a fog net can deliver thirteen thousand gallons a day water vapor needs something to condense on to and tiny particles in the air are perfect where there's lots of pollution there's lots of fog and it can be as dense as it's dirty before London cleaned up its act people came up with some unusual ways to guarantee a breath of fresh air in the afternoon of the weather day after the Sun has heated the earth the condensation process starts to produce cumulus clouds or may arises taking its water vapour with it but as it cools the moisture forms tiny droplets clouds in early scandinavian cultures the clouds were the home of the mythical Valkyries who rode white cloud forces who shiny Mane's scattered frost and do the Valkyries gathered up the slain Viking warriors and took them to Valhalla the hero's paradise we're so used to clouds that we rarely pause to consider their variety or simply their beauty we even make our own clouds contrails are water vapor from airplane exhausts condensing entrails behind big clouds hold millions of tons of water but each droplet is tiny it would take seven billion just to fill a tablespoon eventually enough of them would join together to make a drop heavy enough to fall if the cloud is very high ice crystals form instead of raindrops and eventually make it down to the ground as snow gently falling snowflakes are one thing but howling blizzards are another visibility drops to almost zero and the wind-driven snow piles up in deep drifts pathfinding st. Bernard dogs are their traditional answer in the European house though they're welcome may be owed more to what they carry around their necks they needed more than st. Bernard's in Colorado in 1921 when 76 inches of snow fell in one day but a freeze is always fun for someone being hit by giant hailstones is never fun however the largest hailstone ever recorded weighed as much as a good-sized paperweight monster hailstones are not that unusual they pulverized prompts and do more than 300 million dollars worth of damage every year they can even kill 200 people died in a hailstorm in western Hunan Province China in 1932 we've tried to prevent hail showers at the beginning of the 20th century huge guns were fired into the clouds to prevent hailstones from forming it didn't work in 1902 eleven people were killed by the falling shot stormy weather is often due to weather patterns known as depressions these are borne out of the clash between warm damp air over the tropics and dry cold air from the poles they just don't mix as they collide the warm air rises over the cold cold air chases warm creating vast banks of turbulent air the edges of the air masses are known as fronts winter storms can be particularly severe at sea James the first of England suspected a diabolical plot when he was almost shipwrecked in heavy seas at a trial in Scotland an accused witch Agnes Sampson confessed to creating a storm to kill the king she was burned at the stake on Castle Hill Edinboro in 1592 violently active clouds over the world's largest oceans can generate a deadly spiral dance as the storms move over warm open water more clouds form and the spiral quickens soon the howling whirling mass of energy is heading toward land a hurricane is on the way the destructive force of hurricanes combines 200 mile an hour winds with torrential rain a hurricane picks up two billion tons of water in a single day and when it hits land it just lets go but this monster of weather power provides us with a forecasting success story we can track their course and forecast when they'll arrive on land by late afternoon the sky reflects the intense activity of the weather day we may see rainbows refractions of the sun's rays through water droplets in the air in Norse mythology the rainbow is a bridge between the earth and the gods made from air water and fire this ethereal link was rarely visible to humans the sunset edgers the weather day towards its close the Sun slanting rays pierced the atmospheric soup with gases dust ice crystals and water and split into rich magical colors at the end of the day after the Sun has stirred the air the peace may be shattered by the weather days crowning spectacular the thunderstorm particles rain droplets and ice crystals gyrating collided high in the clouds building up enough energy to light up a small town for a year positively charged particles gathered at the top of the cloud and negative ones at the bottom the energy is discharged as white heat and sound Native American myths tell of a fire a great spirit whose wings crack out thunder lightning as the flash in the Thunderbirds eye a bolt of lightning carries about a million volts and is five times hotter than the surface of the Sun a thunderstorm can release as much energy as an atomic bomb most of it harmlessly into the atmosphere looking from space it's not hard to believe that a hundred people a year are killed by lightning in the USA alone eight to nine million lightning strikes hit the earth each day and don't believe that lightning never strikes twice Rory Sutherland a ranger in Yosemite National Park survived being struck seven times between 1942 and 1977 the Romans felt that their best protection was to wear bay leaves why the gods favored bay is lost in time but the Romans believed it would persuade Jupiter to hurl his Thunderbolts elsewhere medieval Europeans thought that ringing a bell dispersed thunderstorms unfortunately the bell ringers were often struck themselves lightning seeks the most direct route to the earth usually through tall trees and church steeples weather is the greatest natural force we know for good or ill if we're lucky we survived the worst of it and enjoy its benefits rain to grow our food sunshine to warm us a breeze to cool us even violent storms are not all bad in fact they may have been the most important thing ever to happen to our planet it is thought that millions of years ago it was the electrical activity of thunder clouds spark deeper into life