Breakdown: Why positive lightning strikes are more dangerous than negative

Positive versus negative lightning

MEMPHIS, TN (WMC) - Thunderstorms. They are a constant occurrence in the Mid-South, the thunder will boom, the lightning will strike the ground. Did you know there are two types of lightning strikes?

While all lightning strikes are dangerous, in this episode of the breakdown we will explain why positive strikes are considered even more dangerous and deadly than negative lightning strikes.

Negative lightning is referring to the polarity of the lightning strike. A great example of this is a battery that has a + (positive) or – (negative) sign. This sign on the battery represents the type of charge that comes from that end of the power supply. Explaining this in a lightning sense, this means that a transfer of negative charge will occur from the cloud to the ground, thus giving us a negative strike of lightning.

Most (90 to 95%) of the lightning that occurs across the country is considered negative strikes. It is very dangerous as a typical negative charged strike is about 300,000,000 volts and 30,000 amps of power. Way more powerful than a light bulb in your house or a battery that charges your phone.

As for positive lightning strikes, they only make up the remaining 5 to 10 percent of all strikes. Positive strikes originate high in the storm, some 30 to 60,000 feet. Under normal storms, the ground is usually shielded from the positive charges by the negative charges in the middle part of the storm.

That changes when winds are strong in the lower levels, the storm becomes tilted, or when the anvil shape of a storm spreads out ahead or behind the updraft of the storm. Thus, the ground is no longer shielded from those upper positive charges. If the charge between the upper level and ground becomes to large, a downward moving positive charge leader can form.

Due to the shear distance that the positive bolt has to travel to get to the ground, it can be up to 10 times more powerful and last 10 times longer than a negative strike. That means it can reach 1 billion volts and nearly 300,000 amps. The stronger voltage and length of the bolt causes more damage to be done and causes deaths to occur. These strikes can also cause forest fires, house fires and damage planes and power grids.

Positive lightning strikes can also travel long distances from the parent thunderstorm. Up to 20 to 30 miles from the storm, while only 10% of lightning strike victims die from being struck, most are hit from negative strikes. The percentage of positive strike fatalities are quite higher.

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