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There were lengthy and extensive sightings of vertical light pillars in the Philadelphia, Pennsylvania, USA last night from around 7:30 to 8:30 p.m. local time.
See this link for photos and comments: www.nbcphiladelphia.com.

I saw them myself from my home nearly due east, about 25 miles from Philadelphia, which is the 4th largest city in the USA. People living north, west and even south of Philadelphia reported seeing them, as did some other scattered around. You can check the reports yourself.

I found your web site on this phenomenon and posted it on the comments section of the news report above. But I don't think that has garnered much attention and there is still a lot of random speculation. This TV station's weatherman, who didn't see the lights himself, reported that the event was probably "virga" (which I had never heard of), which he described as snowfall refracted by moonlight. I don't think so, given the nature of the phenomenon.

The weather conditions were nearly perfect for the "vertical light pillars in cirriform clouds" explanation. Ground temp was about zero degrees Celsius (32° Fahrenheit) and there were mostly clear skies during the event with snow moving in from the northwest. There was almost no wind, and the area is relatively flat with no mountains. The topography does include some ridges but no mountain peaks. Sunset was at about 5:15 p.m. local time, and I don't believe moonrise was for several more hours, so we can be quite confident that these were not some other kind of light pillars.

There were several VERY bright and stable light pillars and dozens of other fainter light pillars. As in other cases you cite, there are refineries with open-flame burn-off much of the time in the area.

The phrase "vertical light pillars in cirriform clouds" hardly inspires much enthusiasm among people for this unusual phenomenon since it sounds so strange and scientific. May I suggest that you assign a more colloquial name, which I will borrow from one of the other comments I read: "Angels Wings".

I look forward to your response, and I suggest that you contact Glenn "Hurricane" SCHWARTZ at NBC Channel 10 in Philadelphia so he can correct his earlier speculation.

Dan LEVIN
Garnet Valley, Pennsylvania

Our reply :

We are very grateful to Dan Levin for sharing with us his personal sighting of what appears to have been an exceptional spectacle (for more details about the November 19 sightings, see the next entry on this page and the two photos of the lights which we included in our picture galleries).

With regard to the origin of the phenomenon, there can be no doubt: these "vertical light pillars" were unmistakably the mirrored images of ground-based lights reflecting in transparent layers of ice crystals. Immediately after receipt of Mr. LEVIN's mail, we posted this explanation on the NBC Philadelphia Weather Stories forum. Together with several earlier posts with links to our web site, notably by Mr. LEVIN, this seemed to help in putting an end to the random speculation.

In the November 19 display, meteorological conditions were apparently favourable enough for almost every unshielded light to be mirrored in the sky. The quantity and quality of the reflections indicate that the ice-crystal cloud must have been relatively close to the ground (though not close enough to be qualified as "ice mist" because, in that case, the lower part of the pillars would have connected with their light sources). Soundings from a weather balloon released from Pittsburgh on November 20, at 00:00 Zulu Time (i.e. about half an hour before Mr. LEVIN spotted the light pillars) suggest an ice-crystal layer at 2.4 km (1.5 miles). Usually, these cloud layers form at altitudes higher than 3.5 km (2.2 miles), but from time to time they are known to form at lower altitudes as well, especially in northern regions such as Alaska and Finland.

As for assigning a more colloquial name to the pillars, we refer to the final paragraphs of Chapter 2 of our research article on lights pillars in cirriform clouds. At the end of the 19th, beginning of the 20th century, the name "gas comets" was often used to designate the pillars. For several years, we ourselves referred to the lights as "gas flame reflections", but we stopped using that name when we discovered that poorly shielded spotlights can cause them as well. A less technical term would indeed be desirable, but personally we don't think the name "Angel Wings" matches very well the characteristic needle or pencil shape of the reflections.

The pillars seen over Philadelphia are also the subject of one of our case examples.

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Hello, I just wanted to report seeing some light pillars last night near White Haven, Pennsylvania at approximately 00:30 Zulu Time. I thought what I was seeing could have been the aurora but one particular bright pillar looked like a laser beam shining up through the clouds with several fainter ones in a different direction. It was a dark, cold night and some parts of the sky were clear w/ some visible scattered clouds. I did not get any photographs because my camera is not capable of taking pictures in the dark or slow shutter speeds.

Anthony VELGUS
White Haven, Pennsylvania

Our reply :

We replied to Mr. VELGUS in very much the same way as we replied to Mr. LEVIN's e-mail of the same date. The fact that nearly all witnesses described the pillars as stationary and appearing either in the east and southeast (according to reports received by witnesses living west and northwest of Philadelphia) or in the west and south (according to reports from witnesses living east and north of the city), is a clear indication that the lights were not auroral pillars.

The pillars seen over Philadelphia are also the subject of one of our case examples.

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Thanks for the explanation, but now I have another question : does the light source necessarily have to be shining directly up to cause this phenomenon or can the light be at various angles and still cause the pillar to be 90 degrees to the horizon? I do not think there are many lights in this area that send light up as most I ever see are shining down and are mostly shielded.

Anthony VELGUS
White Haven, Pennsylvania

Our reply :

The light sources that cause the vertical pillars do not have to be shining directly up. What counts is that their emitted light reaches the upper and lower surfaces of the transparent ice-crystal plates. Since these crystals are wobbling in a more or less horizontal position somewhere halfway between the light source and the observer, the angle of incidence (and therefore also the exit angle) can be quite small, especially when we are dealing with very distant light sources (see also our simplified diagram). Bright spotlights illuminating buildings and monuments, and even floodlights shining down over playgrounds or football fields can direct enough light to the sky for it to reflect of distant ice-crystal plates. In the latter case, the resulting reflections will have the shape of a series of whitish, parallel streaks close together. The number of streaks depending on the number of spotlights surrounding the field and their position relative to the observer.

Because the distance between the light source and the observer is often in the order of several miles (up to 50 km/31 miles and more!), there usually are no direct visual clues as to which lights are causing the reflections (most of the light sources will be behind the horizon or hidden from view by houses and trees).

The pillars seen over Philadelphia are also the subject of one of our case examples.

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Thanks for the reply and the additional confirmation that is was a light pillar event. The only reason I can think of that even meteorologists would not know about this phenomenon is that it is so rare, particularly to the extent that it was visible on Nov. 19 in a several thousand square km area.

You know much more about weather and atmospheric conditions than I do, but I can assure you that without an easily-remembered name for such an event the public will forever be flummoxed whenever it occurs. But, if it was called something like "Angel Wings", people will remember it and when it occurs there will be much less speculation. And I submit that such a name is close enough to there appearance - since many of the vertical pillars were close together and ephemeral - to stand in for the actual image. (After all, who really knows what angel wings look like?)

This was not my idea or name, but I know a good slogan when I hear it. TV weathermen are also more likely to reference a positive image name that their audience can relate to. This name would leverage your diligent scientific efforts to explain this wonderful phenomenon, as the general public could search on that term and dispel the mystery, but maintain the wonder.

Dan LEVIN
Garnet Valley, Pennsylvania

Our reply :

While it is true that light pillars in high-altitude clouds are not a common thing, they are not really that rare either. We ourselves have managed to photograph them on five occasions (see for example photos with indications OP-PH-06, 07, 11, 12, 13, 14, 15 and 27 in our picture gallery of artificial light pillars). It does help of course if you know where to look. The glow of a distant gas flame for instance can tell you that, if a reflection occurs, it should have the same azimuth as the flame, while the location of the flame will tell you whether the mirrored image will appear high in the sky (when the flame is only a few miles distant) or low on the horizon (when the flame is several tens of miles away).

Regarding the need for an easily-remembered name, we think Mr. LEVIN's point is well taken. Still, we remain reluctant to use the name "Angle Wings", not only because, in our opinion, "Wings" point to a specific shape which the lights do not have, but also because, normally, only very bright lights generate a reflection, meaning that in most cases only one isolated pillar is seen. For that reason, ascribing a name to the phenomenon that can only be used in a plural form, seems a bit odd.

The pillars seen over Philadelphia are also the subject of one of our case examples.

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I'm sure that the phenomenon happens more than it is observed here, but to have on occurrence in a place where the meteorologist don't even recognize it and to have dozens of light pillars visible over hundreds of square kilometers and many compass directions has to be rare.

One other point of local geography of which you may not have been aware is that Pittsburgh is over 500 km (300 miles) from Philadelphia, so I don't know if that impacts the conclusions you drew from the balloon sounding you mentioned or not.

Dan LEVIN
Garnet Valley, Pennsylvania

Our reply :

Although the Pittsburgh weather station from where this balloon was released is about 450 km (roughly 280 miles) west of Philadelphia, it was our best option. With winds blowing from a generally western direction, and knowing that the balloon was released at 7 p.m. while most of the sightings occurred between 7:30 and 9 p.m., we can be pretty confident that the data registered by the Pittsburgh balloon matched fairly closely the atmospheric condition for the Philadelphia area. Still, we admit that an altitude of 2.4 km for the ice-crystal cloud is not to be considered an established fact. We are currently trying to collect additional data that may help determine the altitude of the reflective ice-crystal layer more accurately.

The pillars seen over Philadelphia are also the subject of one of our case examples.

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On the night of November 18th, 2009 I saw about 20 light pillars in the sky above Mihonoseki, Shimane, Japan. It was very strange, I originally thought it might be Aurora, but researching it proved otherwise. They lasted about 2 hours, unfortunately my camera wouldn't pick them up.

Anthony FAULKNER
Sakaiminato, Japan

Our reply

An Internet search brought to light that there are no petrochemical works or gas wells in the prefecture of Shimane that may have caused these light pillars. A more likely possibility therefore is that the pillars were the reflections of bright lights attached to fishing boats (see Section 4 and in particular the black and white photo taken from Fukui showing a group of light pillars caused by a fleet of fishing boats).

We sent Mr. FAULKNER a map of the sighting location and asked him if it would be possible to indicate the direction in which the lights had appeared and give us an estimate of their elevation angle.

Mr. FAULKNER responded right away. Below is the Google Earth image which he returned to us followed by some explanatory notes:

The red X is where I was, the green X is where my friend was and he saw them also. (approx 10 miles away from me) The yellow X's are about where I saw them, about 30 to 40 degree angle. The northern horizon was also pretty bright. In Japan the air gets hazy quite often, not quite cloudy that night but I couldn't see any stars to the north. I could see stars straight up and to the south though. The temperature on the ground was about 5 degrees C.

The black and white picture was almost exactly what I saw, I was thinking it was from fishing boats, since Sakaiminato harbour is the 8th largest fishing port in Japan (I think).

Although I didn't see any pillars close to the horizon, there is a small mountain in the way.

This additional data provided by Mr. FAULKNER pretty much confirms the idea of fishing boats using bright lights to lure squid into their nets.

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I live on the outskirts of Akron, Ohio. Tonight, Jan 28, 11 p.m., took my dog out. As I look on the horizon of this busy city (population of the metro area is 750,000), and look towards the city, vertical shafts of light are rising in the southerly sky. The night is clear, full moon above, few clouds on this horizon but some. I often look to the sky and I have never seen anything like this. I am a 53 year old architect, I have never seen the northern lights here, and when I look away from the city I do not see the lights.

I went to the internet to search for an explanation of this phenomenon, but found none. I found your site and thought I would report this unusual occurrence.

There are approximately 20 shafts of light stretching out over 135 degrees of the southern horizon, some more defined than others. Some/most start near the ground but many go 45 degrees up in the sky. The full moon is directly above.

Any clues to what is causing this effect would be appreciated.

Fred ZUMPANO
Akron, Ohio

Our reply

According to www.wkyc.com, that same night, television meteorologists received calls from other residents in Akron wondering about what appeared to be "beams of light shooting upward from a line of spotlights".

In our reply to Mr. ZUMPANO we pointed out that the description of "vertical shafts of light", "starting near the ground", "some more defined than others" is typical of a display of Artificial Light Pillars, i.e. pillar-shaped reflections from bright, ground-based light sources in clouds of ice-crystals.

In medium climates, these pillars usually appear only in high-altitude clouds, but the very cold temperatures that prevailed in Akron on January 28 (- 12.7°C or 9.1°F at 11:00 p.m.) created the proper conditions for water droplets closer to the ground to turn into billions of tiny, highly reflective ice-crystal plates.

We invited Mr. ZUMPANO to take a look at our gallery with pictures of "light pillars in low clouds" (a sub category of our picture gallery on artificial light pillars). On February 3, Mr. ZUMPANO kindly sent us the following reply: "There is no doubt: what I saw is the phenomenon photographed in OP-PL-08. It was a once in my lifetime occurrence and I thank you for explaining it". We, in turn, thank Mr. ZUMPANO for contacting us.

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