What is precipitation?

Precipitation, in the context of weather, is the result of condensing water vapour falling from the clouds due to gravity. Drops of water or snowflakes inside clouds, which are made up of microscopic water or snow particles, descend to the ground when they get heavy enough. Precipitation takes varied shapes depending on the temperature in the clouds, and it can also take diverse forms depending on the temperatures it meets on its way down.

Precipitation meaning in weather

Most people's lives are affected by precipitation, but what are the many forms of precipitation and how do they form? Rain isn't the only sort of precipitation; there are a variety of other types of precipitation. Each category develops at different temperatures and through various mechanisms. Let's have a look at the many sorts of precipitation. Check the rain radar and where it is raining and snowing now.

Which role does precipitation play in the water cycle?

Every droplet of water makes part of one of the biggest cycles here on earth: the water cycle. Since it’s a cycle, there is no start, nor end, but we’ll start our journey at sea. With the help of the sun and its powerful light, packed with energy, water in oceans, seas and lakes evaporate constantly. Even when the sun isn’t out, at night or in winter. When the water evaporates, its state of matter changes from liquid to solid. That process is called evaporation.

The water vapour rises up in the atmosphere. When the vapour rises higher, it gets colder, and the vapour starts to condensate. The process of condensation results in the water vapour being transformed into small water droplets again. When the condensation process is massive, clouds are formed that can be seen in the current satellite weather.

These clouds move and eventually produce precipitation. When the precipitation reaches the ground, it collects in little streams. This water eventually flows into bigger rivers and ends up in a lake or sea. Another part filters into the ground and ends up in the groundwater reserves, they eventually end up in rivers too after possibly multiple decades. This is the point at which the cycle begins all over again. However, plants ingest some groundwater, which they then return to the atmosphere in the form of water vapour through the process of transpiration.

Precipitation thus plays a major role in distributing the water from bigger bodies of water back again to more inland areas. Without precipitation and the weather more generally, there wouldn’t be a water cycle. All water would be concentrated in oceans and lakes, streams and rivers wouldn’t be present.

The types of precipitation

Rain

Rain is probably the most well-known type of precipitation. It is not only the most well-known, but also the most frequent form in the world. Rain can be formed in both  nimbostratus clouds and cumulonimbus clouds. There are two ways in which rain drops can be formed. The first is the coalescence process. In a nutshell, this is the process of water droplets combining to form larger drops. As long as the temperature in the cloud is above 0°C. So generally on not-too-cold days, and in the cloud's lower layers. When a drop is large enough, it falls to the ground.

Snow

Snow is the second most prevalent type of precipitation. The Bergeron process, as discussed in the previous section regarding rain, is used to generate snow. However, for the ice crystal to descend to the ground, temperatures in most levels of the atmosphere must remain below freezing, resulting in snow on the ground. Snowflakes are small ice crystals that, most of the time, form groups and are viewed as snowflakes. Snow can collect as a snow cover when temperatures at ground level are below freezing.

Hail

Hail is only formed in cumulonimbus clouds. Strong circulating convection currents can be found within these clouds. Particles are transported across the clouds by these currents. Small raindrops that are carried up into the atmosphere freeze. Other little drops adhere to this small hailstone when temperatures drop below freezing again. These droplets freeze when the hailstone is propelled back up, and the cycle begins again. Hailstones can grow to be the size of an egg depending on how powerful the circulation is. When the weight of a hailstone becomes too great, it is carried to ground level, where it can damage cars, houses and injure people and animals.

Sleet and freezing rain

When the ground temperature is below freezing but there is a layer of warmer air above, snowflakes melt into raindrops in this warm layer. Sleet or freezing rain will fall depending on how thick the cold layer is beneath the warm layer. If the cold layer is thick enough, the rain will have enough time to freeze again, this time into small ice cubes rather than snowflakes. It's important not to mix them up with hail. Sleet particles are substantially smaller than hail and develop in a completely different way. The rain will cool, but not freeze, when the layer of cold air is not as thick. However, when the rain reaches the cold surface in this cooled state, it will promptly freeze. Streets can get extremely slippery, because a layer of ice is literally formed on top of them.

Bergeron process

The Bergeron process happens when the temperature is below freezing. Small water droplets that are still liquid form solidify into ice crystals in this situation. If a particle is heavy enough, it will tumble down, just like in the coalescence process. The Bergeron process creates snow at first. It can, however, melt into raindrops when it reaches warmer air layers lower in the atmosphere.