Stephanie Wrote:
-------------------------------------------------------
> How do you explain what we saw in regards to how
> these were formed? My son and I could actually
> see the cloud. This was happening to a thicker
> cirrus cloud...not a very thin one. I have seen
> what you are talking about before. This was very
> dramatically different.
>
> Stephanie

I assume this was as the sun was going down?

This looks a lot what like I'm told the plains tribes called an "eagle feather" sunset, & it IS due to shading.

Basic premise: You see the clouds only because the sunlight hits them (this is why at night you see only dark shapes, or clouds lit by moonlight, starlight, city lights, etc).

If patchy clouds exist just over the horizon, they can block light from the setting sun in some but NOT all places, this results in rays of "shadow" rising up from where the sun is setting.

Being sunset..... perhaps significantly, being premature sunset (courtesy of mountains off on that side of the horizon, or in your case a thunderhead blocking your view of the setting sun), the sky was still blue.

Where sunlight passed uninterrupted into the clouds you saw, the light scattered as it hit them & made the clouds look white to you. Where sunlight was lessened by passing through clouds you DIDN'T see (over the horizon, or on the other side of that thunderhead), not enough of it reached the clouds you saw to make them look White IN THAT PARTICULAR PATH RADIATING OUT FROM THE SUN..... so you saw blue sky through that path (any cloud in it wasn't lit up, was less visible. Eh, consider the analogy of dust in the air.... if just dust by itself you can see right through it without noticing, But a strong flashlight beam, or sunlight through an open window, can light up the dust (via light scattering as it hits it) in a less than outdoorsy dim room. To continue the analogy, the dust in the air is like the clouds in the area above the thunderhead. When hit by sunlight it lit up like the dust & looked "white" to you. When NOT hit by sunlight, you saw right through it & saw the blue sky on the other side. Eh, imagine a grid of TINY lights.... when turned on you see white glare, when turned off you see right past them to whatever is beyond. If some lights don't get power due to blocked wires, you'll see streaks of dark where those wires/lights are).

Note how in some photos (I recall #2), some blue streaks were irregular at the bottom, but in a linear fashion (bottom border was horizontally irregular, vertically regular)... this was due to variation in the patchy clouds that you couldn't see (thick = totally block light & you see a blue streak all the way down, thinner = partially block light & it only goes so far before petering out, and you see a blue ray that doesn't reach down as far, hole in clouds you don't see means FULL light goes up & illuminates the clouds so that you see white cloud in that region).

This is VERY common where I am, due to the many mountains to the west, the many clouds (moist ocean air hitting mountains & rising & cooling to form clouds), and all the dust (desert valley) here.

I've some beautiful photos of this somewhere, don't think on disk. Eh, I know ONE on disk, but it was of a single dark blue line going straight up from the sunset like a beacon!

Kenuchelover.