Fire Rainbows

“Fire Rainbows” are neither fire, nor rainbows, but are so called because of their brilliant pastel colors and flame like appearance. Technically they are known as circumhorizontal arc - an ice halo formed by hexagonal, plate-shaped ice crystals in high level cirrus clouds. The halo is so large that the arc appears parallel to the horizon, hence the name.

Brightly colored circumhorizontal arc occur mostly during the summer and between particular latitudes. When the sun is very high in the sky, sunlight entering flat, hexagon shaped ice crystals gets split into individual colors just like in a prism. The conditions required to form a “fire rainbow” is very precise – the sun has to be at an elevation of 58° or greater, there must be high altitude cirrus clouds with plate-shaped ice crystals, and sunlight has to enter the ice crystals at a specific angle. This is why circumhorizontal arc is such a rare phenomenon.

A colourful circumhorizon arc spans the sky near Fredericton, New Brunswick, Canada, in 2003.

The position of the observer is also important. Circumhorizontal arcs cannot be seen in locations north of 55°N or south of 55°S. Likewise there are certain times of the year when they are visible. For example, in London, England the sun is only high enough for 140 hours between mid-May and late July. While in Los Angeles, the sun is higher than 58 degrees for 670 hours between late March and late September.

Circumhorizontal arcs should not be confused with Iridescent clouds, which can produce a similar effect. While circumhorizontal arc occur only in cirrus clouds, iridescence often occur in altocumulus, cirrocumulus clouds and lenticular clouds but very rarely in cirrus clouds.

Circumhorizon arcs are so large that sometimes we see only parts of them where they happen to 'light' fragments of cirrus cloud. Ed Johnson (site) captured this one on June 8, 2003 on Mount Baden-Powell, California

Circumhorizon arcs are so huge that their colours sometimes appear to be those of the sky itself rather than an ice crystal halo. In this long-lens shot the halo forms a backdrop to a seemingly tiny aircraft. Picture taken at Pilesgrove, New Jersey in July 22, 2007

This circumhorizon display was photographed through a polarized lens above Dublin, Ohio, in May 2009.

Circumhorizon Arc in Alentejo, Portugal, 2006.

Circumhorizontal arc in Scottsdale, Arizona in 2009

Cirrus fragments lit by a circumhorizon arc, Halifax, Nova Scotia, on 3rd July 2001 with the sun 66° high.

This peculiar 'braided' circumhorizon arc was possibly formed by plate crystals in high cirrus fibratus cloud. Pictures taken at Silver City, New Mexico, USA during August 2004.

Circumhorizontal arc seen over Switzerland in June 2007

Circumhorizon arcs are often seen between lower obscuring clouds. This one was seen in Redding, CA in June 2004.

Circumhorizontal arc in Spokane Valley in June 2006

Circumhorizontal arc seen in Spokane Washington State, in June 3, 2006 when the sun was 64° high


Amazing Camouflage of Walking Leaves

Leaf insects or walking leaves are some of the most remarkable leaf mimics in the entire animal kingdom. These insects take the appearance of a leaf to hide themselves from predators. They do this so accurately that predators often aren’t able to distinguish them from real leaves. In some species the edge of the leaf insect’s body even has the appearance of bite marks. To further confuse predators, when the leaf insect walks, it rocks back and forth, to mimic a real leaf being blown by the wind.

The creature may have been first documented by the scholar Antonio Pigafetta, who sailed with the Portuguese explorer Ferdinand Magellan and his crew on their voyage to the Indies in the 15th century. He studied and chronicled the fauna on the island of Cimbonbon as the fleet hauled ashore for repairs. During this time he documented the Phyllium species with the following passage:

In this island are also found certain trees, the leaves of which, when they fall, are animated, and walk. They are like the leaves of the mulberry tree, but not so long; they have the leaf stalk short and pointed, and near the leaf stalk they have on each side two feet. If they are touched they escape, but if crushed they do not give out blood. I kept one for nine days in a box. When I opened it the leaf went round the box. I believe they live upon air

Leaf insects occur from South Asia through Southeast Asia to Australia. At present, there is no consensus as to the preferred classification of this group, but they are generally treated as the Family Phylliidae.


Amazing Clouds That Look Like Things

Spotting shapes in clouds is a delightful way to pass a lazy afternoon. There's even a society dedicated to cloud spotting. It’s called the Cloud Appreciation Society, founded by Gavin Pretor-Pinney to foster understanding and appreciation of clouds, and to fight “blue sky thinking”.

A clear blue sky has always been associated with good, happy weather – a perfect summer’s day, while cloudy skies are regarded as a metaphor for doom. Nothing could be more depressing, it seems, than to have ‘a cloud on the horizon’. Gavin Pretor-Pinney decided that this has to stop. “Someone needs to stand up for the clouds”, he says. So in 2004, he started the Cloud Appreciation Society and few months later launched a website. People sent in their cloud photograph, which he put up on the gallery pages for others to look at. The early trickle of submission soon swelled to a torrent. Today, it has over 29,000 members worldwide from 83+ different countries, and many thousands of amazing images.

Below is a collection of some of the most peculiar cloud formations.

A cloud monkeying around over Bangkok. Photo by Alex Cliff

Cloud Alien ahead.....Eagle River Valley, Colorado. U.S. Photo by Terry Robinson.

Aladdin's lamp, spotted over The Torres del Paine National Park, Chile. Photo by Andrea Andreoli.

A baby floats over Zurich, Switzerland. Photo by Danièle Siebenhaar.

The big chicken on the roof of Manor Market in Bishop California, is being mirrored in the clouds. Photo by Andrew Kirk.

A dolphin leaping from an inky black sea over Sussex, UK. Photo by Beryl Pratt.

Dolphins at play, Sausalito, California. U.S. Photo by David Holbrooke.

A heart in the clouds over Norwich, UK. Photo by Doug Taylor

A Dove over Kent, UK. Photo by Pauline Reay-Earnshaw

Eagle soars over Cambridge. U.K. Photo by Christie Nel.

Elephant in a storm cloud, taken on holiday at Patong Beach, Phuket, Thailand. Photo by Graham Blackett.

A feather over Brockenhurst in the New Forest, Hants., UK. Photo by Chris Gleed-Owen

A heart over SuperDevoluy, Saint Etienne en Devoluy, France. Photo by Emily Morus-Jones

A hummingbird over Berryton, Kansas, US. Photo by Shannon Franks

Jack Palance, spotted over Loudonville, Ohio, US. Photo by Catherine Wilson

A jellyfish over Berry, New South Wales, Australia. Photo by Mark Muirhead.

A cumulus called Kitty, Western New York. U.S. Photo by Diane Mariotti.

A man running with a bouquet of flowers. Spotted over France. Photo by Rudolf Wehrung.

A giant Mushroom over North Jutland, Denmark. Photo by Jan Hertoghs

Poodle spotted over Sanderstead, Surrey. U.K. Photo by Alex Brooker.

A poodle with shades enjoys a day by the sea over Blackpool, Lancashire, UK. Photo by Bill Williamson.

A rabbit hopping over Nottinghamshire, UK. Photo by Andy Jamieson.

Shhhhhh dont tell anyone. There's a monster rat over Tortona, Alessandria, Italy. Photo by Pietro Cordelli.

A sunset smile over West Hollywood, California, US. Photo by Christine Murphy.

Little Cumulus cloud from East Texas, US, smoking. Photo by Jan Morris Marek.

A snail, spotted just before sunrise over Anglesey, UK. Photo by John Rowlands

A turtle travelling on the back of a crocodile over the border between France and Spain. Photo by Jean-Francois Guillot

A witch or the grumpy old man in the muppets over Bangkok. Photo by Alex Cliff.

The iconic scene from TV programme The Apprentice, when Lord Sugar says "you're fired", acted out over Bangkok. Photo by Alex Cliff