Friday Fotos: Mysterious Ice Circles

Last month we did a Friday Foto post about a magical frozen bubble lake and while researching it, we stumbled upon another type of mysterious frozen beauty called ice circles.

According to Wikipedia, an ice circle, ice disc or ice pan is a natural phenomenon that occurs in slow moving water in cold climates. Ice circles and discs have most frequently been observed in Scandinavia and North America, but they are occasionally recorded as far south as England and Wales.

Ice circles are thin and circular slabs of ice that rotate slowly in the water. It is believed that they form in eddy currents and they vary in size with some reported to be more than 4 metres (13 ft) in diameter.

Ice discs form on the outer bends in a river where the accelerating water creates a force called ‘rotational shear’, which breaks off a chunk of ice and twists it around. As the disc rotates, it grinds against surrounding ice — smoothing into a circle.

Ice pans are surface slabs of ice that form in the center of a lake or creek, instead of along the water’s edge, according to river specialist and geography professor Joe Desloges. As water cools, it releases heat that turns into frazil ice — a collection of loose, randomly oriented needle-shaped ice crystals that can cluster together into a pan-shaped formation.

There are many gorgeous photos and videos about ice circles online and below are some of our faves…

Sheridan Creek, Rattray Marsh in Ontario, Canada (Source)

Lake Baikal in Russia (Spotted by ISS astronauts)

 Russia (Source)

See more cool ice circle photos and watch a short video on FeedFury.com … and have a great weekend everyone! 🙂 j & B

Friday Fotos: Venezuela’s Catatumbo Lightning provides brilliant light shows 10 hours per day

According to Amusingplanet.com, the Catatumbo Lightning is one of the coolest natural phenomenon on earth. It occurs strictly in an area located over the mouth of Venezuela’s Catatumbo River where it empties into Lake Maracaibo. Over this relatively small area powerful flashes of lightening more than 5 km in height strike at surprising frequency – during 140 to 160 nights a year, 10 hours per day and up to 280 times per hour.

Theories abound as to why the lightning is concentrated in one area all the time. Some scientists say that the geological features around the Catatumbo River basin contribute to a constant low-pressure system. That would explain why the lightning hasn’t stopped for more that a few months at a time for thousands of years.

Stormchaser.ca writes the frequent, powerful flashes of lightning over this relatively small area are considered by some to be the world’s largest single generator of tropospheric ozone.

Images: AmusingPlanet.com 

Stay safe and have a great weekend! j & B