The remaining frozen portion either falls to the lower portion of the cloud or continues on to the ground. The charge separation has an electric field associated with it. Like the cloud, this field is negative in the lower region and positive in the upper region. The strength or intensity of the electric field is directly related to the amount of charge build-up in the cloud.
As the collisions and freezing continue to occur, and the charges at the top and bottom of the cloud increase, the electric field becomes more and more intense -- so intense, in fact, that the electrons at the Earth's surface are repelled deeper into the Earth by the negative charge at the lower portion of the cloud. This repulsion of electrons causes the Earth's surface to acquire a strong positive charge. All that is needed now is a conductive path so the negative cloud bottom can conduct its electricity to the positive Earth surface.
The strong electric field creates this path through the air, resulting in lightning. The lightning is a high-voltage, high-current surge of electrons, and the temperature at the core of a lightning bolt is incredibly hot. For example, when lightning strikes a sand dune, it can instantly melt the sand into glass. The combination of the rapid heating of the air by the lightning and the subsequent rapid cooling creates sound waves.
These sound waves are what we call thunder. There can never be thunder without lightning. Sign up for our Newsletter! Mobile Newsletter banner close. If conditions are right, the cloud will continue to build and build into a cumulonimbus cloud, which typically reaches a height of 25, ft.
Within cumulonimbus clouds there are updrafts and downdrafts. The updrafts carry moisture and water droplets up so high that they freeze and form ice crystals or hail. During this point, the ice particles bump into each other and give off electrical charges: positive and negative. The lighter positive charged ice crystals are forced to the top of the cloud, while the heavier negative charged hail gather at the bottom. The negative charge is attracted to the positive charges in the cloud, and any in other nearby clouds as well as the positive charges on the ground.
It is these discharges that lead to the sudden flashes of light and loud rumbles, commonly known as thunder and lightning. Lightning is a large electrical spark caused by the negative charges moving from one place to another. And the quick expansion and heating of the air due to the lightning is what leads to the rumble of thunder.
The ingredients needed for thunderstorms to form include ample amounts of unstable air and a temperature structure where there is warm near the ground and cold air above it. This weather layout is most common during spring and summer than autumn and winter since there is more sunlight and longer time in the day for the sun to warm up the Earth's surface.
Many hazardous weather events are associated with thunderstorms. Under the right conditions, rainfall from thunderstorms causes flash flooding, killing more people each year than hurricanes, tornadoes or lightning. Lightning is responsible for many fires around the world each year, and causes fatalities.
Hail up to the size of softballs damages cars and windows, and kills livestock caught out in the open. Strong up to more than mph straight-line winds associated with thunderstorms knock down trees, power lines and mobile homes. Tornadoes with winds up to about mph can destroy all but the best-built man-made structures. Where are severe thunderstorms most common? The greatest severe weather threat in the U. But, no place in the United States is completely safe from the threat of severe weather.
A watch can cover parts of a state or several states. Warnings mean there is a serious threat to life and property to those in the path of the storm.
ACT now to find safe shelter! A warning can cover parts of counties or several counties in the path of danger. How does a thunderstorm form? As the air rises, it transfers heat from the surface of the earth to the upper levels of the atmosphere the process of convection.
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