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Lightning is THE number one underrated weather hazard. Every year 1000 or more people are struck by lightning with nearly 100 deaths due to these strikes.
- The Genesis of Lightning?
- Lightning is basically a large static charge stored between the upper and lower levels of a cloud. A clouds upper level contains positive charged molecules of moisture and the bottom portion contains negative charged molecules. Based on the same principals as a common capacitor.
Evaporated moisture rises and collides with ice and sleet molecules suspended within the cloud, these collisions cause a separation of an electron. The stripped electrons pool at the bottom of the cloud and the positive charged droplets rise to the top of the cloud. This separation is called an electric field, the strength of the electric field increases as more and more collisions occur.
As the electric field builds strength, it begins to repel the electrons at the earth's surface deeper into the earth. This in turn creates a positive attraction between the electrons in the lower cloud to the earth's newly acquired positive charge. "Like charges repel, opposite charges attract".
- Lightning is basically a large static charge stored between the upper and lower levels of a cloud. A clouds upper level contains positive charged molecules of moisture and the bottom portion contains negative charged molecules. Based on the same principals as a common capacitor.
- The Strike
- Once the electric field becomes strong enough, it causes dielectric breakdown of a path of air between the cloud and the earth. This is called ionization; the product of ionization is plasma (fourth state of matter). The zigzagging pattern of a lightning bolt is because the air is not ionizing equally. Impurities, such as dust allow air to ionize more easily producing a more random pattern.
Leaders in the cloud follow the path of least resistance through the air and 'lead' the way for the main electric charge to follow. In turn, positive charges from the earth send up short 'streamers' toward the leaders. Once a leader and streamer connect, a conductive path to ground is complete and the main charge flows and is what we commonly refer to as lightning.
- Once the electric field becomes strong enough, it causes dielectric breakdown of a path of air between the cloud and the earth. This is called ionization; the product of ionization is plasma (fourth state of matter). The zigzagging pattern of a lightning bolt is because the air is not ionizing equally. Impurities, such as dust allow air to ionize more easily producing a more random pattern.
- Thunder
- Lightning produces temperatures that are hotter than the sun. (Think welder or arc-furnaces used to melt steel...on a larger scale) This extreme heat literally causes the air around the lightning bolt to expand with explosive velocity. The expanding shock wave creates the sound heard and sometimes felt after a lightning strike. Depending on the proximity of the strike, people and structures can be harmed or damaged by lightning shock waves. A shock wave is produced approximately 10 yards from a strike, which degrades to basic sound waves thereafter.
- Lightning Energy
- Energy is a unit measure of horsepower, heat, or watts. The energy associated with lightning is the product of voltage and current or watts. According to experts that have studied lightning, voltages are typically in the tens of millions of volts and average currents ranging from 8000 to 20,000 amps. Fortunately, not all this power is delivered to the strike area; a good portion of this energy is dissipated in the form of heat while traveling the mile or more to the ground.
- Lightning Safety
- Contrary to popular belief, lightning doesn't need a direct hit to cause damage. After lightning strikes the ground it doesn't travel directly into the ground and dissipate, but travels outwards on surface of the ground from the strike point.
A few things to remember if you are caught outside during a lightning storm. • Don't run under a tree in an attempt to stay dry, find shelter in a car or building if time allows.
• Don't lie flat on the ground; crouch down with your feet together while keeping your head low.
• An open umbrella is not a good idea during an electrical storm. Close the umbrella and seek shelter indoors if possible.
If you are indoors, stay off the phone. If you must call someone, use a cordless phone or cell phone. If lightning strikes the phone line, the strike will travel to every phone on the line (and potentially to you if you are holding the phone).
Stay away from plumbing pipes (bath tub, shower). Lightning has the ability to strike a house or near a house and impart an electrical charge to the metal pipes used for plumbing. This threat is not as great as it used to be, because PVC (polyvinyl chloride) is often used for indoor plumbing these days. If you are not sure what your pipes are made of, wait it out.
- Contrary to popular belief, lightning doesn't need a direct hit to cause damage. After lightning strikes the ground it doesn't travel directly into the ground and dissipate, but travels outwards on surface of the ground from the strike point.