The simplest definition of Precipitation is any form of water that falls from the sky. Evidently, any precipitation develops in Earth’s atmosphere and then falls to the surface, usually as rain.

Precipitation is part of the water cycle, and thanks to this component, living organisms get the freshwater they need to survive. After falling, it evaporates and rises into the atmosphere as a gas, condenses, and falls again. This process repeats over and over again.

Each year about 505,000 km3 of water fall to the Earth´s surface; 398,000 km3 on oceans and 107,000 km3 on land. It means that on average, annual rainfall is about 99 centimeters. 
But precipitation is different in each region of the world. For example in Georgia, USA, the rain falls evenly during the year, about 102-107 centimeters annually, while in Arica, Chile, it didn’t rain for 14 consecutive years. Then, rainfall can vary across a region, area, or even a city.

It means the conversion of water vapor into a liquid that accumulates around tiny dust particles, forming clouds.

Causes of Precipitation.

Precipitation falls to Earth after a condensation process. It means the conversion of water vapor into a liquid that accumulates around tiny dust particles, forming clouds. When the droplets become too heavy, gravity pulls them down. Let´s explain it further:

During the water cycle, the process of evaporation causes liquid water from the oceans, rivers, lakes, and other bodies of water and even plants to become water vapor in the air. This vapor rises and accumulates in the atmosphere, forming clouds. Clouds are made mainly of water droplets, dust, ice, and salt. When they rise high enough, they become cirrostratus clouds, high-level clouds composed of ice crystals, and altostratus clouds, thick clouds made of ice and water.

Eventually, clouds fill with microscopic water droplets, which grow heavier; this happens due to air turbulence that moves droplets around and joins them. When they’re eventually heavy enough to overcome air resistance, they fall to Earth surface. All types of precipitation originate in the clouds.

Rain, a type o precipitation.

Types of Precipitation.

It is the precipitation in the form of drops of liquid water. Unlike its traditional representation, drops are spherical and not shaped like teardrops. They can have a diameter up to 6 mm; if drops are less than 0.5 mm, it is called drizzle.


Snow is precipitation in the form of ice crystals. Its formation takes place in clouds when water vapor is sublimated and forms delicate ice crystals. When they fall, they join and form snowflakes, and therefore each flake has a complex structure based on crystals of frozen water, but they are soft if touched. According to the temperature and humidity, the snowflakes develop diverse patterns.

Precipitation allows plants to grow and agriculture to be successful provinding food for humans.


It is the precipitation in the form of pieces of ice, created when chilling water droplets freeze at the top of the clouds. When they become larger, due to the binding of the frozen drops, air currents can’t hold them in the clouds, and these ice pieces fall. Given their size, they do not melt before reaching the Earth’s surface. Most Hail has a diameter of 25 mm, but they can be as large as 150 mm or as small as 5 mm.



Sleet is rain and snow mixed that freezes before it hits the ground, creating ice pellets.

Another lesser-known kind of precipitation is diamond dust, which is composed of small ice crystals formed at temperatures not exceeding -30°C.

Needless to say, that precipitation is the basis of life. If the water vapor in the air just remained suspended there, bodies of water would dry up, and life would be impossible. Precipitation allows plants to grow and agriculture to be successful provinding food for humans.



By definition, a blizzard is an extended, severe snowstorm. In order to qualify as a blizzard, winds have to be at least 35mph and rage for a longer period of time—at least three hours or more. The amount of snowfall has little to do with a storm qualifying as a snowstorm, but rather the intensity of the wind and length of time. There are two other classifications for blizzards:

–Severe blizzard: winds over 45mph, temperatures at 10 Fahrenheit or lower, near zero visibility.

–Ground blizzard: no falling snow, snow from the ground is blown by the strong winds.

A nor’easter gets it’s name from the direction of the oncoming winds. This occurs on the Atlantic side of Canada and East Coast of the USA. These storms can start as far south as the Gulf of Mexico or the North Atlantic Ocean. However, the most common usage of the name is in the coastal regions of Atlantic Canada and New England. These storms are similar to a hurricane. One of the deadliest blizzards in the USA—the Great Blizzard of 1888—was a nor’easter, killing 400 people after dumping 40-50 inches of snow.

What causes blizzards?

Blizzards are usually formed when the jet stream pitches very far south. This allows the cold air that comes from the north to collide with warm air coming from the south. This creates a strong storm system, usually developing on the northwest side of such storm systems.

Any area which is mostly flat is susceptible to blizzards, though there are some areas in the US, Australia, and the UK that suffer from blizzards more than others. However, the deadliest blizzard in recorded history occurred in Iran in 1972.

Dangers of blizzards

Blizzards are one of nature’s deadlier storms, as the conditions make travel and movement hazardous. Snowstorms disrupt traffic, but blizzards make any kind of travel nearly impossible. Almost every blizzard results in at least a few deaths, with some of the bigger ones resulting in hundreds of people dying.

Visibility is drastically reduced, in some cases to as little as 3 meters or what is called zero visibility.  In a ground blizzard, though no new snow is falling, the snow already on the ground is whipped up and around by the winds to where visibility is also close to zero.

Travel under these conditions is close to impossible. Cars have to come to a complete standstill as they can drive off the road. Because blizzards rage for so long, people can get trapped in their cars, freezing to death as they wait for it to clear. Once the storm is over, cars are often buried under mounds of snow, making it difficult for rescue teams to find them. Hypothermia sets in as people trapped outdoors try to find shelter and warmth.

Blizzards have been known to come suddenly and while it is possible to be warned in advance, it’s not always possible to be entirely prepared for the intensity of the blizzard. Clearing roads is not possible until after the blizzard has passed and then takes a long time due to the intensity of the build up. The aftermath of the blizzard can be almost as dangerous as the storm itself, as people trapped inside vehicles, unheated buildings, or outdoors take longer to be found and brought to warmth and safety.

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Snow covered car

History of blizzards

Though not as common as snowstorms, tornadoes, or even hurricanes, blizzards are deadly every time they hit. Not all blizzards are mentioned here, not even all of the most severe. This is just a sample of the havoc that blizzards can wreak.

–The white winter of 1880-1881 is one of the earliest blizzards mentioned in history books. This is considered the worst winter in US history. Because the first blizzard hit in October, before most farmers had the opportunity to bring in their crops. One after the other the blizzards continued to hit, making travel impossible, even by train. People were at the brink of starvation and train services stopped completely by January 1880 as no matter how often they cleared the tracks, another storm would come and cover them again. The snow never thawed and on February 2, 1881 a nine day blizzard hit again. By then, towns and farmers had to tunnel through the snow to get to livestock, wood for heating, and supplies.  Once the snow started melting, huge areas were flooded, washing away huge areas around the Missouri river. The town of Yankton, currently South Dakota, was nearly completely washed away by the overflowing river.

–The Iran Blizzard of 1972 is the deadliest recorded blizzard. Starting on February 3, until February 9, more than 10 feet of snow fell, the worst areas in Southern Iran getting up to 26 feet of snow. Whole villages died, one being completely buried beneath the snow. Approximately 4000 people died.

–The Armistice Day Blizzard in 1947 came somewhat unexpected, resulting in a lot of deaths. On the morning of the blizzard, the weather was warm, resulting in many hunters going out to take advantage of ideal conditions. Within a few hours, the blizzard hit, raging through the night and into the next day. 145 deaths were reported as a result of the 1,000 mile wide storm. Many hunters were not dressed warmly enough to withstand the wind and snow. Many were stranded on islands in the Mississippi, or drowned trying to get back to land.

–The Schoolhouse Blizzard in 1888 is different from the nor’easter and in some ways more heart breaking. Because the day started out relatively fair, people went about their lives, with children going to school and adults going to work. The storm hit early in the day, leaving thousands stranded; mostly children in their one-room schoolhouses. 235 people died; including children.

Although meteorologists are now able to more accurately predict blizzards, the storms still have the ability to cripple whole cities at a time, and deaths are almost always inevitable. Over the years, rescue missions during and after blizzards are becoming better and preparedness goes a long way towards preventing large amounts of casualties. It has also become considerably easier to notify people of oncoming storms, with more reliable predictions and getting the word out quickly and effectively.

Countries which are not used to large amounts of snow, extreme cold, and long periods of strong winds tend to have a harder time coping when the storms hit. Regardless of where the blizzards hit, there is never a way to be completely prepared. There is always a chance of power outages, communications systems breaking down, people going for long periods with little or no heat, and getting trapped outdoors or in a vehicle. During winter months, people are advised to pay close attention to weather warning coming over the radio or TV. There are weather websites set up to help people prepare for blizzards and post warnings when a snowstorm is being upgraded to a blizzard.


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What is an Avalanche?


One of the worst positions to find yourself is being stuck in an avalanche. Death is a very likely factor when you are entrapped in a snow slide. 90 percent these unfortunate events occur when a human is on a mountain with snow either skiing, snowboarding, or snowmobiling so this is something to consider the next time you decide to do any snow activities.

An avalanche is simply a quick flow of snow down a slope. This happens in a starting zone when the forces on the snow are too heavy for its foundation. The lower they get down the slope, the more they grow in mass because it is accumulating more snow as it goes downhill.

Avalanche Contents

Even though a snow slide is usually composed of air and snow, it can accumulate much more things going downhill such as ice, rocks, trees, and pretty much anything else on the slope making it extremely dangerous for travelers on the mountain that are caught in it.

When Do Occur and How Often?

Avalanches are not rare or random events that occur once in any particular area. They usually happen during winter or spring but movements in the glacier can cause avalanches at any given time. In mountainous terrain, snow slides are one of the most dangerous natural hazards to life and property because they are able to destroy almost anything in its way with an immense amount of snow at high speeds.

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Avalanche Facts and Information

Ten Deadliest Avalanches in History


  • In January of 1954, Blons, Austria saw one of its worst avalanches to date. 118 people were buried. While rescue workers were trying to get them out, another unexpected avalanche came and wiped them out.


  • In World War II, the Italian and Austrian military had bases in the Alps. On what is now known as “White Friday”, the Alps witnessed a series of avalanches claiming the lives of 10,000 soldiers, none of which guessed that enemy fire or bombs would be the least of their worries.


  • One of the most Ironic cases is the one that took place in Wellington, Washington on 1910. Three trains that were carrying 119 people were delayed at a station house so that they didn’t have to travel in poor weather. Unfortunately, an avalanche defeated the whole purpose of the stop when it swept the trains over a 150-foot cliff.


  • In 1970, Mount Huascaran was devastated by rock ice and snow cascading swiftly which caused 80,000 people to die and left around one million people homeless.


  • In the Rhone Valley of Switzerland and France, in 1720 the Galen Avalanche took 88 lives and 100 buildings. This avalanche caused numerous fires that led to the destruction of the town.


  • In 1618 on September 4, The Rodi Avalanche in Switzerland ripped through an entire city burying 2,500 people alive. No one survived the avalanche, however, 4 people who were away returned home only to find their entire community, homes, and friends destroyed.


  • The famous “Winter of Terror” which plagued the Swiss-Austrian Alps in 1950-1951 consisted of almost 650 sub-avalanches that claimed 265 lives. These events were caused by warm air currents combining with polar air currents, causing much more precipitation than the area could manage.


  • Instigated by blizzard conditions of wind and snow, the Lehaul Valley Avalanche in the Himalayas buried 200 people under 20 feet of snow in 1979. This was the only avalanche in the Himalayas to make it to the top ten list of most dangerous avalanches in the world.


  • Leaving only 50 people alive, the avalanche in Ranrahirca, Peru happened several years before the Great Peruvian Earthquake. Snow, mud, rock, and frozen debris fell down from Mount Huascaran smothering the whole village of Ranrahirca, leaving over 2,700 people dead and destroying every house in its path.


  • In 1965, construction on the Mattmark Dam, which is the biggest dam on earth, caused 12 men to lose their lives. A part of the Allalin Glacier broke off and fell onto the building site destroying everything in its path.


Natural Causes of Avalanches

Even though humans usually instigate avalanches, they obviously happen other ways as well. They can happen when there is an increased load of snowfall. Melting from solar radiation is another natural way that avalanches happen. Rain, icefall, rock fall, earthquakes trigger avalanches as well, depending on the circumstances. It is always important that you pay attention to weather reports if you are planning on doing any snow activities where there is a possibility that an avalanche can occur.

Different Types of Avalanches

There are different avalanches that are categorized by the characteristics of the avalanche. Knowing what areas are prone to certain types of avalanches can be helpful when planning to go on a ski trip or any activity involving being on a mountain with snow.

Loose Snow Avalanches

Loose snow avalanches are common in steep terrains. They usually occur in snow that has just fallen. Also, they can happen in old surface snow that was moistened by heavy solar radiation. Loose snow avalanches usually start at the point of the slope and widens as it travels downhill, using more snow. It resembles a teardrop, and large loose snow avalanches can result in slab avalanches.

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Snowslide in Switzerland

Slab Avalanches

Slab avalanches are formed when snow is deposited, or re-deposited by wind factor. They look like a block of snow cut out from its environment by fractures. These slab avalanches vary in thickness. They can be from a few centimeters to a few meters. Slab avalanches cause 90 percent of avalanche-related fatalities.

Powder Snow Avalanches

Powder snow avalanches form currents of turbulent suspension, in which they are the largest. This is a cloud of powder that lies over an avalanche that is dense. These form from any type of initiation structure or snow, but most of the time happens with dry, fresh powder. These types of avalanches can go move faster than 300km/h carrying a mass of 10 million tones. They can also travel long distances on a flat surface and uphill for a short amount of time.

Wet Snow Avalanches

Wet snow avalanches tend to be low in velocity suspension and consist of water and snow. The low speeds are caused by friction between the sliding surface of the track and saturated water flow. Although these types of avalanches tend to move slowly, they can still cause great damage with powerful destructive forces because of its large mass and density. Wet snow avalanches can consume boulders, earth, trees and other things in its path. These avalanches can be triggered by loose snow releases, or slab releases occurring only in snow packs that are saturated by water and equilibrated isothermally to the melting point of water. These types of avalanches usually happen towards the end of a winter season, when there is an immense amount of daytime warming.

In the end, any of the above avalanches could cause you to lose your life. With that being said, when you are out on the slopes trying to catch major footage, keep in mind that if a mountain is feeling too much pressure, you could be making your final recording.


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