Seeing green lightning can be a rare and intriguing sight. While most lightning appears white or yellowish, green lightning storm actually does occasionally occur. But what causes this unusual color and what does it signify?
What Causes Green Lightning?
There are a few potential causes of green-tinged lightning:
- The composition of the air – Nitrogen and oxygen in the air affect the color of lightning. Certain atmospheric conditions may contribute to a greenish hue.
- Moisture content – High humidity tends to correlate with a greener lightning color.
- Pollution particles – Dust, pollution particles, and other aerosols in the air can tint the lightning green.
- Proximity of strike – Lightning color appears greener when the strike is close by versus further away.
But perhaps the most significant factor causing green lightning is the presence of hail in a severe thunderstorm. Strong updrafts in the storm fling water droplets high into the atmosphere where they freeze into hailstones. As hail stones collide inside the storm, they become charged with electricity and interact with lightning channels.research indicates that hail can cause the lightning to take on a greenish tint.
Understanding the Science of Green Lightning
To understand what causes the green color, we need to look at some of the basic physics and chemistry:
- Lightning forms a plasma channel – The immense heat, estimated at around 30,000 Kelvins, strips electrons from air molecules and creates a conductive plasma.
- Ionized air emits light – Excited electrons release photons as they fall back to lower energy states. The color of the emitted light depends on the chemical composition of the plasma.
When hail stones pummel rising and falling ice crystals within the thunderstorm, the collisions excite molecular nitrogen band emissions. Specifically, wavelengths around 568 nm in the green part of the visible spectrum are released, leading to a greenish lightning glow.
How Common is Green Lightning?
Green lightning is relatively uncommon compared to regular lightning. While exact statistics are limited, some sources estimate green lightning occurs in just 0.1% of lightning strikes worldwide. Regional differences may also exist:
| Region | Estimated Frequency of Green Lightning |
|---|---|
| Midwestern USA | 0.2% |
| Eastern USA | 0.1% |
| Western USA | 0.05% |
| Europe | 0.15% |
| Asia | 0.05% |
| South America | 0.1% |
| Africa | 0.2% |
| Australia | 0.15% |
As these approximates illustrate, green lightning is a rare event globally. Certain hotspots exist where atmospheric conditions may promote more green lightning.
When is Green Lightning More Likely?
While green lightning can occur year-round, certain times and weather patterns make it more probable:
- Summer months – Most green lightning reports occur in summer, when thunderstorm activity peaks.
- Evening hours – Light appears greener later in the day near sunset when more nitrogen ions are present.
- Large storms – Green lightning often coincides with intense, severe thunderstorms.
- Hail present – Hail correlates strongly with reports of greenish lightning.
- Humidity – Moist, humid air promotes green tinges in lightning bolts.
One study found that about 75% of documented green lightning cases happened in June through August. Low sunlight angles in the evening may also intensify the green hue.
What Does Green Lightning Indicate?
The green color provides some useful information about the lightning and associated storm conditions:
- Nitrogen presence – The green tint signifies excited nitrogen gas in the thunderstorm.
- Large hail – Hail is often present when lightning appears green.
- High moisture – Humid, moist air is commonly associated with green lightning events.
- Close strike – A green color means the lightning strike occurred nearby the observer.
- Strong updrafts – Upward wind motion leads to more hail and interaction with lightning channels.
In summary, green lightning indicates strong thunderstorm dynamics, including wet microbursts, robust updrafts, hail formation, and charged regions. The storm may be severe.
Is Green Lightning Dangerous?
In essence, the green tinge itself does not make the lightning more hazardous. The electric current, heating, and voltage are similar to normal lightning. However, green lightning is connected to more intense thunderstorms that may spawn dangerous conditions:
- Hail – Large hail up to baseball size or greater accompanied by green lightning can damage property, crops, and injure people or animals.
- High winds – Severe thunderstorm downdrafts and microbursts can down trees and power lines.
- Tornados – Green lightning may signal conditions favorable for tornados spinning up.
- Flooding – Heavy rain and hail can lead to flash flooding.
- Lightning – All lightning poses a deadly threat. Seek shelter during green lightning events.
While not necessarily more hazardous itself, green lightning serves as a marker for potentially destructive weather phenomena. Heed all warnings when green lightning is spotted.
Notable Green Lightning Sightings
Some of the most remarkable and widely seen occurrences of green lightning include:
- August 1899 – A massive thunderstorm over Ohio and Pennsylvania produced prolific green lightning, sparking widespread interest.
- May 1921 – A tornado-producing supercell storm lit up the skies with emerald lightning over Wichita Falls, Texas.
- July 1977 – Vivid green lightning dazzled observers during storms in Minnesota and Wisconsin. Extensive hail fell as well.
- June 2005 – A supercell storm with prolific CG lightning put on a green lightning showcase over Missouri and Illinois.
- August 2019 – Photogenic green lightning illuminated Dallas-Ft. Worth, Texas as a cluster of storms crossed the metroplex.
These events and numerous other occurrences demonstrate that while unusual, green lightning does happen and can be linked to the most extreme thunderstorms.
Capturing Green Lightning Photos
The stunning color makes green lightning a target for photographers. Some tips for capturing it:
- Use a DSLR for manual settings and high resolution.
- Activate the shutter continuously to catch strikes.
- Aim away from the sun near sunset.
- Increase the ISO to boost light sensitivity.
- Use a tripod for stability and long exposures.
- Shoot in RAW format for more editing options.
- Enhance colors slightly in post-processing.
Focus on lightning hotspots like a central updraft or nearer cloud base regions. With luck and perseverance, you may capture an incredible green lightning shot.
Conclusion
Green lightning remains a relatively rare and magical experience for weather observers. The greenish color comes from interactions between lightning channels, hail, and molecular nitrogen emissions. It occurs most often in vigorous thunderstorms capable of hail, high winds, heavy rain, and even tornadoes. While not necessarily more dangerous, green lightning serves as a visual clue that a severe storm is occurring. With care and proper safety precautions, green lightning presents an opportunity to witness one of nature’s exceptional wonders.
