You’re standing in the middle of a frozen field in Manitoba or maybe Northern Norway, teeth chattering, eyes glued to a sky that has turned a bruised shade of purple. Suddenly, it happens. A massive, brilliant green ribbon begins to dance, twisting like a neon snake across the stars. This is the show you paid for. But then, you notice something else. Just below that emerald glow, or sometimes slicing right through it, are these strange, vertical white stripes. They don't shimmer. They don't move with that ghostly, liquid grace of the Aurora Borealis. They just sort of... sit there.
Most people point and scream, "Look at the white aurora!"
They're wrong. Honestly, those white stripes under great northern lights are usually something else entirely. If you’re seeing sharp, picket-fence lines that look like a celestial barcode, you’re likely witnessing a phenomenon called STEVE or perhaps just a very specific trick of light and atmospheric chemistry that has nothing to do with the solar wind hitting our ionosphere in the way we usually think.
The STEVE Mystery and Those Ghostly Picket Fences
For decades, amateur "citizen scientists" and aurora hunters in groups like Alberta Aurora Chasers kept reporting a thin, mauve or white ribbon of light. It didn't look like the curtains of the Northern Lights. It looked like a jet contrail that had somehow caught fire. In 2016, researchers finally sat up and took notice. They named it STEVE. That stands for Strong Thermal Emission Velocity Enhancement, which is a mouthful, but the name actually started as a joke reference to the movie Over the Hedge.
What’s wild is that the white stripes under great northern lights—the ones that look like vertical bars—are often the "picket fence" associated with STEVE.
These stripes are basically a river of superheated gas. While the green aurora happens when electrons from space smash into oxygen atoms about 100 to 150 kilometers up, STEVE is different. It’s a sub-auroral phenomenon. It’s caused by a 25-kilometer-wide ribbon of hot plasma flowing at speeds of about 6 kilometers per second. That is incredibly fast. To put it in perspective, that’s faster than a speeding bullet, and it’s happening right over your head.
The white or pale green "picket fence" stripes you see are actually waves of turbulence in that plasma flow. They appear lower in the sky than the main red or purple ribbon of STEVE. If you see them, you aren't just seeing "faint aurora." You are seeing a literal river of heat in the upper atmosphere.
Why Does It Look White to You?
Here is the thing about human eyes: we are kind of terrible at seeing color in the dark.
Our retinas use two main types of photoreceptors: cones and rods. Cones handle color but need a lot of light to wake up. Rods are great for low light, but they are colorblind. When the Northern Lights are faint, or when those vertical stripes appear, they often don't have enough "luminous flux" to trigger your cones. So, your brain just defaults to grayscale.
That’s why your friend with the expensive Canon camera is freaking out about the "vibrant pinks" while you’re standing there thinking the sky looks like a dusty white sheet.
However, there is a rare version of the white stripes under great northern lights that is actually "white" even to a camera. This happens when there is a massive mix of different emissions. If you have oxygen (green) and nitrogen (red/blue) all firing at the same time in the same pillar of light, the colors can "wash out" and appear white to the naked eye. It’s like mixing all the colors on a palette; eventually, you just get a messy, bright neutral.
Light Pillars: The Optical Illusion That Fools Everyone
Sometimes, the white stripes you see aren't even in space.
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They’re in your neighborhood.
If it’s a bitterly cold night—we’re talking "it hurts to breathe" cold—the air near the ground gets filled with tiny, flat ice crystals. These are often called diamond dust. When there’s a bright light source on the ground, like a streetlamp or a stadium light, these ice crystals act like millions of tiny mirrors. They reflect the light back to your eyes in a vertical column.
These are called light pillars.
If there happens to be a great display of Northern Lights happening at the same time, the light from the aurora can reflect off these same crystals. This creates white stripes under great northern lights that look like they are reaching down to touch the houses. It’s a spectacular optical illusion. But if you walk a hundred yards to the left, the "stripe" will move with you. It’s not a physical object in the sky; it’s a reflection that exists only in your specific line of sight.
The Chemistry of the Glow
Let's get technical for a second, but not boring. The sky is basically a giant neon sign.
In a standard aurora, the colors are predictable:
- Green: Atomic oxygen at lower altitudes.
- Red: Atomic oxygen at very high altitudes (harder to see).
- Blue/Purple: Molecular nitrogen.
So where does white fit in?
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When the solar storm is incredibly "hard"—meaning the particles are moving with insane amounts of energy—they penetrate much deeper into the atmosphere. They hit the thicker air down around 80 to 100 kilometers. Down there, you get a mix of everything. The white stripes are often the result of this high-energy "bombardment" where the light becomes so intense and the spectrum so broad that it overwhelms the typical green.
It's a sign that the solar storm is particularly violent. If you see white streaks, check your GPS or your radio. You might notice some glitches. That's because the same energy creating those stripes is currently messing with the Earth's magnetic field.
How to Tell the Difference When You’re Out There
If you’re standing in the snow and you see a white stripe, how do you know what it is?
First, look at the shape. Is it a perfect vertical line coming from the ground? It’s probably a light pillar. Ice crystals are the culprit.
Is it a thin, jagged line that looks like a fence? That’s likely the STEVE picket fence. You’re looking at plasma physics in action.
Is it a broad, shimmering white curtain? That’s a high-energy aurora. It’s usually moving fast, flickering, or "pulsating."
Actually, there is a fourth option. High-altitude clouds. Noctilucent clouds are "night-shining" clouds made of ice crystals seeded by meteor dust. They usually appear in the summer months at high latitudes. Sometimes they catch the light of the aurora or the sun from over the horizon and look like glowing white ribs in the sky.
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Real Examples from the Field
Photographer Alan Dyer, a legend in the aurora-chasing community, has captured these "picket fence" stripes multiple times. His work helped researchers understand that these white and green stripes aren't just "part of the aurora." They are actually a signature of a specific type of atmospheric turbulence.
In 2023, during one of the largest solar storms of the decade, observers as far south as Arizona reported seeing these white and red streaks. The fact that people saw them that far south tells us that the "river of heat" (the STEVE phenomenon) was incredibly pushed away from the poles. It wasn't just a pretty light; it was a map of a distorted magnetic field.
Why This Matters for Your Next Trip
If you’re planning a trip to Iceland, Fairbanks, or Yellowknife, don't just look for the green. The green is common. The white stripes are the "rare loot" of the sky.
They usually appear during the "substorm" phase. This is when the aurora suddenly brightens and expands rapidly. If you see the sky start to "unravel" and those white streaks appear, get your camera ready. Use a fast lens (f/2.8 or better) and keep your shutter speed under 2 seconds. Any longer and those crisp white stripes will just blur into a messy white smudge. You want to freeze the motion of the plasma.
Common Misconceptions to Throw Away
People love to say that white aurora is "just a reflection of the moon."
Nope.
While the moon can wash out the colors of the aurora, it doesn't create organized, vertical white stripes. Another one is that it's "pollution." Also wrong. While light pollution makes it harder to see the lights, the white stripes we're talking about are high-altitude phenomena. They are purely natural (and purely awesome).
Actionable Insights for Your Aurora Hunt
If you want to catch the white stripes under great northern lights, follow these steps:
- Monitor the Hemispheric Power Index. If the number is above 50 or 60 GW, the storm is strong enough to produce high-energy white emissions.
- Look South of the Main Oval. If you are in a place like the Yukon, look slightly south of the main green curtains. That is where STEVE and his white picket fence usually hang out.
- Check the Temperature. If it’s -20°C or colder and you see white stripes near the horizon, look for nearby light sources. You’re likely seeing light pillars, not space weather.
- Use Your Phone's Night Mode. Even if you can't see the color, modern smartphones (iPhone 15/16 or Pixel 8/9) are surprisingly good at picking up the subtle pinks or greens in those "white" stripes. If the photo comes back green, it’s oxygen. If it comes back mauve, it’s STEVE.
- Watch the Movement. If the stripe is "pulsing"—on and off like a heartbeat—you are seeing pulsating aurora, which involves high-energy electrons from the magnetosphere's "chorus" region.
The sky is never just one thing. It's a messy, chaotic, beautiful laboratory. Those white stripes aren't glitches in the show; they are the most interesting part of the physics. Next time you see them, don't just think the aurora is "fading." You’re likely looking at a high-speed river of gas or a rare atmospheric reflection that most people go their whole lives without ever noticing.