Picture captured by Lisa Bishop, from the South Hill area of Puyallup, WA (don't try to pronounce it, even auto-spell tells me it's spelled incorrectly).
It is the highest volcano in the Cascade Volcanic Arc, standing at 14,410 feet.
The phenomenon occurs when the sun rises behind the mountain, causing its shadow to project onto the cloud deck, creating a dramatic visual effect. The event is rare and happens mid-October to January when the sun's position aligns perfectly with Rainier's peak, AND it's a clear day (which makes it even really rare, given our weather).
I see the mountain every day from my neighborhood, and by that, I mean the days when it's not cloudy and raining.
This is a most beautiful sunset but am I the only one whose mind can't get that shadow to "compute?" There's nothing in the shadow but birds and maybe an airplane. The remaining content of the shadow cone is just pristine air. The only things that become dimmed are the birds that enter the cone; they pop back to full illumination when they fly out the opposite edge. The cone is not a physical thing; it is just an effect. So why is the red sky background dimmed behind the shadow? Shouldn't it appear to the camera in full brightness? Why would an unrelated shadow block its natural view? Why do we see the shadow at all?
@Northwest There are no discernible crepuscular rays in your photo. Such rays are illuminations of the atmosphere that contains lots of matter—especially water droplets. They’d appear as rays emanating from the sun and would show up brightly, not dimly. The dim mountain shadow is not a ray at all; it is the absence of a ray. It does not “emanate” except in a poetic sense. Since this shows a day of low humidity with no haze (and consequently unlimited visibility,) it contains little matter, not enough to dim the clouds from showing brightly through it. A shadow does not emanate; it is merely evidence of a blocking of an emanation. Being nearly empty of matter, it cannot block light coming from behind it.
Hijacking your thread was not my intent. Let me first apologize and then suggest we continue this side issue via DM if you like.
@katydidnt The intent of the picture was not to get into an endless discussion, or to explain what a shadow is, or why an analysis of 5th Ave in New York does not provide a context, or that 350 daya out of the year, and specifically on this October day, there is no humidity in Puyallup, but here we are :-), so I guess we'll into the Physics.
The Scene
Mount Rainier is backlit by the rising sun. The sky is filled with a dense layer of mid-altitude clouds, which are glowing orange and red due to the low-angle sunlight. However, a dark triangular “shadow beam” seems to stretch upward from the mountain’s peak across the fiery sky.
What Causes the Shadow
That “beam” is the shadow of the mountain, projected onto the underside of the clouds in the atmosphere.
Here’s the step-by-step physics:
Low Sun Angle – The sun is near the horizon, so its rays travel almost horizontally.
Opaque Mountain – The mountain blocks the sunlight, casting a shadow into the air.
Cloud Layer at Altitude – When there are clouds high enough to intercept the shadow, the mountain’s silhouette appears projected onto them.
Perspective Illusion – Because the shadow extends away from the observer and converges toward the horizon (like railroad tracks), it looks like a long, narrow beam pointing up or out of the mountain’s summit.
Why the Colors Are So Intense
At sunrise or sunset, sunlight travels through much more of the Earth’s atmosphere. Blue and green wavelengths are scattered out, leaving behind reds, oranges, and pinks. The contrast between the glowing clouds and the mountain’s shadow exaggerates the effect.
Why It Looks “Unreal”
Even though the shadow physically extends away from the sun, from the viewer’s standpoint it appears to emanate from the mountain and climb the sky. This visual contradiction tricks the brain, making it seem like a mysterious beam of darkness cutting across a glowing sky.
So, what looks like a “dark ray from the mountain” is really the mountain’s own shadow cast onto the glowing clouds—a breathtaking example of light, geometry, and atmospheric optics working together.
This is somewhat commonly seen at Mount Rainier, Mount Hood, or Mount Fuji. I'm lucky to see Rainier on near daily basis, and Mount Hood every once in a while and have seen Mount Fuji during a few trips.
@Northwest I see the problem. You're thinking those clouds are low enough to nearly skim the mountaintop, where to my eye they are far, far above that elevation and well behind and above the mountain. Your premise permits your argument, because within the shadow are the clouds themselves, close up and with plenty of matter to be darkened by the blockage of light. Assuming now that my estimate of the mountain/cloud separation misses the reality of the day, I concede. Now I can enjoy the photo without reservation. Thank you.
