Greenwood Crown Flash

mrfintoil

Senior Member.
This thread might not be so much about debunking the video, as internet already seems to have pinpointed the phenomenon as a rare weather phenomenon called crown flash.


The effect looks very cool, but I find very little information about the phenomenon. Perhaps because it is so rare and hard to study. Anyone got a good source on this phenomenon?

Or just post some kooky UFO-interpretations of this video, for amusement :D
 

Mick West

Administrator
Staff member
There's a good collection of links here:
http://amasci.com/amateur/sundog.html

I particularly like the Forgetomori article, with historical descriptions found by the late William Corliss
http://forgetomori.com/2011/science/a-new-natural-phenomenon-crown-flash/


[X1. July 2, 1970, Ann Arbor, Michigan. While observing a thundercloud. "At and just above the peak of the storm cell the cloud mass seemed to be undergoing sudden changes in brightness lasting for several seconds at a time…. The phenomenon continued to occur repeatedly at intervals of 30-60 s during the next 15 or 20 min, providing the basis for the following description. The sudden brightening effect began
concurrently with lightning strokes in the main cloud mass, but continued after the lightning flash was over. It had the appearance of a ripple-like upward and outward spread of radiance from the region just west of the peak of the cumulus cloud, resembling somewhat a fan-like display of aurora borealis. It lasted a substantial fraction of a second with each lightning stroke. On one or two occasions it had the appearance of a bright ring moving rapidly outward and upward above the cumulus peak. On these occasions it was clearly observed to extend beyond the cloud and into the blue sky. A linear shadow, apparently cast by one of the cumulus masses, appared to shift its position suddenly up or down with each occurence of the event."
X2. August 18, 1950. St. Albans, England. "At 12.25 GMT a cumulo-nimbus of moderate size was passing about four miles to the south, and giving rumbles of thunder about once every minute. While observing the cloud my attention was drawn to a bright streamer, apparently of cloud, projecting northwards from the anvil top for a distance of five degrees. As I watched, the streamer suddenly ‘exploded’ into a rapidly widening circle of light, fading as it did so. Immediately afterwards the streamer started to reform in the same place as before, only to repeat its ‘disappearing’ act again after a minute or so, presumably whenever an electrical discharge took place. On some occasions the streamer shifted violently to one side, changing its form greatly, but always returning to one spot. The spectacle lasted for half an hour, becoming fainter as the cloud moved away eastward."
X3. April 30, 1885. Denison, Texas. A glowing region repeatedly travels along the tops of thunderclouds that were arranged in a long bank.
References
R1. Gall, John C., jun., and Graves, Maurice E.; "Possible Newly Recognized Meteorological Phenomenon Called Crown Flash," Nature, 229:185, 1971. (X1)
R2. Hale, R.B.; "Unusual Lightning," Weather, 5:394, 1950. (X2)
R3. "Electrical Phenomena," Monthly Weather Review, 13:103, 1885. (X3)]
Content from External Source
 

Henk001

Senior Member.
Phil Plait (Bad Astronomer) paid some attention with a rather extensive explanation for this two days ago:
http://www.slate.com/blogs/bad_astr...ctric_cloud_phenomenon_makes_light_dance.html
What's happening here is a wispy cirrus cloud, made up of ice crystals, is being impinged upon from below by a rising cumulus cloud. If the ice crystals in the cirrus are long and needle-shaped, they'll align themselves with the electric field of the lower cumulus cloud, which is generated by up- and downdrafts inside the cumulus cloud. When the electric field suddenly changes (due to, say, lightning discharges inside the cloud), the ice crystals can snap into a different orientation, reflecting and refracting sunlight in a different direction (note that the plume in the video is the same color as the Sun). They do this as a group, making it look like huge coherent structures are suddenly changing shape.
Content from External Source
 

SR1419

Senior Member.
Incredibly cool.

"i'm fn flipping out dude" was classic.


Its easy to see how in an earlier time in human history you might be convinced somebody was up there.
 
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