Somewhere under the rainbow!
UPSIDE DOWN RAINBOW WAS SEEN IN SKY OVER THE REGION
APART from the rich blue sky and wispy clouds drifting over Hull and the East Riding on a day where temperatures reached 20C, one other stunning natural phenomenon grabbed the attention of some.
Best described as an upside down rainbow, the sight spotted on Wednesday evening is actually a circumzenithal arc.
The Mail received several pictures from readers of the rare phenomenon above the city and in the neighbouring East Riding.
Although there was one lighthearted suggestion was that it was the outline of Planet X, an undiscovered planet at the heart of doomsday theories, it appears more likely to be a type of halo that is formed in a similar way to a normal rainbow.
However, unlike rainbows, these are formed when sunlight refracts through ice crystals, as opposed to through water droplets.
Pictures were sent of the arc from Hull North Ferriby.
More details on how they circumzenithal and
are formed can be found on the Met Office website, www.met office.gov.uk, which reads: “A circumzenithal arc (sometimes known as Bravais’ arc) is a type of Halo.
“They are formed when sunlight refracts through horizontal ice crystals at such an angle that the light enters the crystal through its flat top face and exits through a side prism face causing the distinctive upside-down rainbow effect.
“They are commonly associated with cirrus clouds where ice crystals readily form.
“Circumzenithal arcs are actually quite common as these types of clouds occur throughout the year, however we only sometimes see them as they are usually obscured by clouds underneath.
“In order to be able to see a circumzenithal arc, a combination of atmospheric conditions must coincide.
“The height, depth and position of the ice clouds must be right as the cloud needs to be at a specific angle convex to the sun.
“The position of the observer is also important since its visibility can vary greatly over short distances.”