Purwakarta - The phenomenon of hail is precipitation in the form of ice in various sizes and irregular shapes. The size of the falling ice can be from 5 to 50 millimeters. This hail has the potential to be dangerous and destructive if it occurs on a large scale, for example causing damage to the roof of a house. While the meaning of Precipitation is the process of falling all material that is poured from the atmosphere to the earth's surface in the form of liquid (rain) or solid (snow / ice crystals). Precipitation is part of the hydrological cycle.
Even so, the phenomenon of hail is a common thing, especially in the tropics. Hail generally occurs in the transition season accompanied by rain of bees, lightning, and strong winds.
In meteorological terms, hail is also called hail. Hail is produced by cumulonimbus clouds and only occurs for a short time, which is less than 1 hour.
|The process of hail
The process of hail is not much different from ordinary water rain, the difference is in the process of condensation or evaporation. The process of condensation is when water vapor turns into ice particles which are affected by low air temperatures at high altitudes.
The main cause of hail is freezing in this condensation process. Precisely when there is sudden condensation due to the movement of air masses up and down very strongly in the Cumulo Nimbus clouds. Until a very strong air mass forms large ice particles.
|Cumulo Nimbus clouds
That's the cause of hail and the process that actually occurs. Hail is local rain with an area ranging from 5-10 km only. The duration of the hail is also short, at most 10 minutes. The occurrence of hail is more frequent in the afternoon or evening.
Reporting from the official LAPAN website, the hail process is formed from:
1. The process of hail begins with the condensation of very cold water vapor through the atmosphere in the upper layers of the frozen level. The ice formed generally has a large size.
2. There are two ways the appearance of hail, namely:
a. When a large collection of ice in the atmosphere descends to a lower, warmer area, hail occurs. But sometimes not all the ice will melt completely and make it hail.
b. A riming event, which is when cold water vapor is attracted to the surface of the ice seeds. This sudden condensation process triggers the formation of large-sized ice and falls to the earth as hail.
3. The formation of hail due to ice particles or frozen raindrops, develops by absorbing very cold cloud grains in cumulonimbus clouds. The grains pass through the freezing level with temperatures below 0 degrees Celsius or at an altitude of about 16,000 feet
Indication of hail events in some tropical countries.
1. The air on the night of the previous day until the morning was very hot and stifling due to the presence of strong solar radiation. This is indicated by the value of the difference in air temperature between 10.00 and 07.00 LT (> 4.5°C) accompanied by quite high humidity as indicated by the value of air humidity in the 700 mb layer (> 60%).
2. From 10:00 in the morning, Cumulus clouds appear, which are white clouds in layers. Among the clouds there is one type of cloud that has a very clear border that rises like a cauliflower, with a gray color. The next stage is that the cloud will quickly change color to gray or black, this cloud is known as a Cb cloud (Cumulonimbus).
3. The trees around you, their branches or branches will begin to sway quickly. There will also be a touch of cold air. The first rain that falls is usually a sudden downpour. As for if the rain is drizzling then the occurrence of strong winds is far from your location.
4. When the transition season does not rain for one to three consecutive days, then there is an indication of the potential for heavy rain to fall for the first time followed by strong winds.