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Three explanations were offered for this multiple witness sighting of a gigantic "UFO" over Montreal: a display of the aurora borealis [1]; spotlights from a nearby construction tower shining through a thick fog [2] the same spotlights, but reflected off of the clouds [3].

The aurora explanation certainly sounds promising, but verification learned that there was no solar activity of note recorded on November 7, 1990. Furthermore, the overcast cloud deck, together with the ambient light pollution in Montreal, would have made it impossible to see the aurora that night.

The second and third possibility can be discarded on the ground of the following lines from the HAINES/GUENETTE report:

"Officer Lippé contacted the superintendent of a 45 story commercial building being built across the street to the West from the Bonaventure Hotel (at 1000 de La Gauchetière, the tallest building in Montreal) to turn off all of the intense construction lights which were located on the top of a construction crane. As expected, no influence was noticed on the appearance of the object when these lights were extinguished".

A huge, lighted object, photographed and observed by highly credible witnesses, deserves a solid explanation. We believe the key to the mystery can be found in a news item that the Canadian Broadcasting Company (CBC) dedicated to the sightings on the fourth birthday of the incident [4].

The opening shot of this 10 minute long film, shows an aerial view of downtown Montreal at night, including a close up of the outdoor swimming pool on the rooftop of the Bonaventure Hotel. Interestingly, at the bottom of the pool there are six bright spotlights beaming skyward through the water. They appear to be the brightest unshielded lights anywhere near the hotel. Is it possible that the mystery object was a reflection of the pool lights in a high-altitude cloud of ice crystals? If so, the size of the mirrored image should be identical to that of the original, but the investigation showed that the longest axis of the "oval body" measured probably between 585 m and 1,504 m, whereas the longest axis of the pool measures 15 to 20 m at most!

the swimming pool

The image to the left is a picture of the heated swimming pool on the roof of the Hilton Bonaventure hotel. The aerial view on the right shows the same swimming pool at night filmed from a helicopter. Six spotlights are mounted at the bottom of the pool. The dark dot in the center is a swimmer.
[Left picture taken from Night view taken from the opening scene of "CBC Newswatch", broadcast on November 7, 1994]

The sizes given by HAINES and GUENETTE (H & G) were calculated from estimates of angular size and distance. While the angular size was determined by asking six witnesses to estimate the apparent size of the object at arm's length in centimetres or inches, the minimal and maximal distances were obtained from estimates of the object's position with regard to the cloud base (3,500 feet), and from estimates given by an Air Canada pilot who was also on the rooftop that night and situated the object between 8,000 and 10,000 feet. Although the authors admit that 'humans are not good estimators of distances or angles when using their memory of an earlier event', they do not take this observation into account when trying to determine the size of the phenomenon. The visual angles calculated from the witnesses' estimates vary from 1° 50' (estimate given by GUENETTE) to 45° (estimate given by the pool's lifeguard)! Only the smallest estimate (1° 50') was noted down on the day of the sighting. All other estimates (ranging from 11° 55' to 45°) were obtained at least 9 and a half months after the event. Despite the fact that they have serious doubts about the accuracy of such estimates, the authors settle on an average angular width for the main body of the object of 27°.

This choice of 27° is even more difficult to understand when H & G write that the visual angle of 1° 50' given by GUENETTE himself "is remarkably close to the measured visual angle obtained from the two photographs", namely "1° 14 min. arc for the first picture and 1° 17 min. arc for the second". According to the report these angles "define the distance between the two luminous areas in the photos that are farthest apart from one another and determine the longest axis of the 'oval body'" (unfortunately only three of the six lights are discernable on the low quality images included with the report). Being a ufologist, GUENETTE was probably aware of the grotesque exaggerations that are often made when witnesses try to estimate the size of an object at arm's length. As such, his personal estimate should be considered more reliable than those of the other five witnesses. H & G argue that, probably, GUENETTE only saw one of the pencil rays due to his vantage at street level where the nearby buildings blocked his view. However, this explanation for the small visual angle given by GUENETTE is refuted by what the authors wrote elsewhere, namely that GUENETTE’s estimate of the size matches the size obtained from the pictures remarkably well. Moreover, GUENETTE described "a small greenish Aurora Borealis-like phenomenon with long streamers extending out from it" (our emphasis). This clearly suggests that GUENETTE had a view of the entire phenomenon, and certainly of its central body.

The sketch by La Presse reporter Marcel LAROCHE is another indication that a visual angle of 1.5° should be regarded as much closer to reality than the other estimates. On his sketch, LAROCHE compares the diameter of the object's "body" with that of the Moon (which has an angular size of only 0.5°!). Comparisons with known celestial bodies (such as the Moon or a bright star) are always much more reliable to work with than estimates at arm's length.

Let us stick with the hard evidence and do the math again starting with the first of the two pictures taken by LAROCHE. According to H & G, the linear width of the longest axis of the central body measures 0.370” on a 8” x 12” enlargement. This means that the linear width of the image on the 35 mm negative was 1.079 mm. This measurement can be converted to the real size of the phenomenon for any assumed value for the distance using the formula that holds that the size of the photographed object equals the size of the object’s image on the negative divided by the focal distance (50 mm) and multiplied by the distance between the camera and the object (in our case the distance to the cloud base which we believe acted as a reflective layer). According to weather data gleaned from the records of the Dorval International Airport [5], there was a cloud layer at 4,500 feet at 8:30 pm which had lowered to 4,200 feet at 9:00 and to 3,500 feet at 9:30 pm. From this we can safely assume that, when Mr. LAROCHE took his first picture, i.e. at 9:10 pm, the cloud base was between 3,500 and 4,200 feet (1,148 m and 1,377 m). Since the pictures were taken from the rooftop of the hotel, we have to subtract 65 m (the average height of a 17 story building) from these altitudes. This gives 1,083 m for the minimum and 1,312 m for the maximum distance between the camera and the phenomenon. To obtain the size of the phenomenon we have to multiply these distances by 1.079 and divide the result by 50. We get 23.4 and 28.3 m. In other words, not that far away (compared to 585 and 1,504 m) from the average length of a swimming pool (the pool at the Hilton hotel being "about 15 metres long", according to a traveller's review on

H & G point out that the angle subtended by the phenomenon in the second shot is slightly larger (1° 17' instead of 1° 14'). According to the authors, this suggests "either that the object decreased in altitude, tipped in angle, or physically changed in size between the time the two photographs were taken". There is, however, another possibility, namely that the reflected image was now closer to the camera because of the descending cloud-base.

The majority of the sketches gathered by H & G either show six to eight lights arranged in an oval, or a partial circular arc with three or more small lights along its length. In interviews, the witnesses explained that the lights had different sizes and that there were white rays of light protruding from them, each ray beginning and ending abruptly, and the larger the diameter of the light, the longer the ray. As with most nocturnal UAP sightings that involve multiple witnesses, here too we notice important differences with regard to the number of lights, their colour and position. In these circumstances, a photograph - no matter how little detail it shows - is often a much more reliable piece of evidence to work with.

The pool lights visible in the helicopter shot from the CBC news item, are six in number. They are arranged in a semi circle and are not all equally bright. These variations in intensity are probably due to the fact that each of the lights reaches the camera under a different angle. It is also quite likely that the lights are mounted on an inclined pool surface, meaning that some lights will be deeper under water than others. The three lights visible on the UFO pictures display a similar appearance as the ones in the helicopter shot and are also positioned on one side of an imaginary circle (or oval).

According to a line drawing made from a high quality print of the first picture, there are three more lights visible in the original document, two of which are located on the opposite side of the "oval body" and one at its lowest point. Apparently, these lights are very faint because they do not appear in the colour reproductions that are inserted in the report. Moreover, the positions of the two opposite lights, as sketched by H & G, suggest that they may have been caused by internal camera reflections of the two brightest lights in the picture.

H & G are puzzled by the fact that "the end of each ray appeared to stop abruptly rather than taper to zero brightness gradually". They ask themselves if this may not have been "the result of air ionization along well defined energy paths". More likely is that the abrupt ends of the beams mark the end (actually the base) of the ice-crystal cloud [6]. Such narrow beams with sharply defined ends or tips appear in many pictures of pillar-shaped reflections created by ice-clouds. Of special interest is the striking resemblance between the lights in the photos taken by Mr. LAROCHE and the reflections photographed by Joël BAVAIS in the Belgian community of Ath in 2006 [7].

The reflection hypothesis not only explains the aspect, the immobility and the disappearance of the unidentified lights, it also explains why, apparently, the best spot to observe them was the rooftop of the Bonaventure Hotel. And perhaps even more important, it tells us why the phenomenon could be captured on camera but went undetected by radar, despite the fact that it was well within the radar range coverage.

And finally, by way of comparison, we publish three rare photos of spotlights and city lights mirrored in high cloud.

Artificial light pillars appearing near the zenith light pillars over Portland

Artificial light pillars appearing near the zenith. Top left: the lights over Montreal [original photo by Marcel LAROCHE as published recently on] / Top centre: light pillars over Paris, France / Top right: light pillars over Ath, Belgium / Below: light pillars over Portland, Oregon. For full-frame versions and additional info about these light pillar shots, click on the respective city names.

 Our opinion

All the evidence in this major Canadian case points in the direction of a remarkable optical phenomenon, namely a reflection from the under water lights of a swimming pool in a cloud layer of ice crystals.

Addendum on next page >> 

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 Notes & References

[1] This possibility was mentioned in the CBC news item.

[2] See (French). On this forum, that is managed by the "Sceptiques du Québec", someone who worked close to the Bonaventure Hotel at the time of the sightings, suggested that the unidentified lights were construction lights from a tower that served to get materials to the top of a much larger building at 1000 de la Gauchetière. The writer in question, who calls himself "brio39", speculates that a gust of wind had bent the tower towards the roof of the Bonaventure hotel. According to brio39, the bright lights shining down on the rooftop in this way, together with a thick fog that obscured the upper part of the tower, could easily have created the illusion of a UFO.

[3] This possibility is considered by HAINES & GUENETTE themselves.

[4] The news item in question can be viewed at

[5] The Dorval International Airport, later renamed as Montreal Pierre Elliott Trudeau International Airport, is located at 8 miles (13 km) west of the hotel. Its elevation is slightly more than 100 feet (about 35 m) above mean sea level, which is about the same as that of downtown Montreal. The data from the airport revealed that:
- the weather was generally clear at 7:30 pm with a thin layer of scattered clouds at 6,700 feet above ground level (visibility was 15 miles).
- at 8:30 pm there was a scattered layer of clouds at 3,000 feet and an overcast layer at 4,500 feet.
- by 9:30 the cloud ceiling had lowered to 3,500 feet.
- at 10:00, when the object was seen to slowly fade out and finally disappear completely, the clouds were developing into very opaque, thick snow clouds from 4,000 to 5,000 feet thick.
- temperatures near the ground were just below zero that night and there was a slight breeze, with the wind coming from the west (later northwest) at 4 km/h increasing to 9 km/h.

[6] According to the weather data obtained from the Dorval International Airport the air temperature near the ground was -1° C at 8:00 pm. This suggests that temperatures were well below zero at altitudes above 3,500 feet (1,148 m). Tiny ice columns and hexagonal plate-crystals (only these two crystal types have large enough surfaces to reflect light back to the ground over such distances) form at temperatures from 0° to -25° C.

[7] For more info on pillar-shaped reflections observed near the zenith, see also Chapter 4 of our article Light pillars in cirriform clouds.