Rare fire rainbow spotted over South Carolina
Wednesday, August 19, 2015, 3:53 PM - A rare 'fire rainbow' is making headlines after it was spotted in the sky over South Carolina Monday, remaining in the area for about an hour before fading away.
The phenomenon -- dubbed a ''fire rainbow'' by a Washington journalist in 2006 -- is formally referred to as a circumhorizontal arc and, while rare in Canada, it isn't unheard of.
Dayna Vettese, a meteorologist at The Weather Network, says the conditions have to be ''just right'' for the arcs to appear.
"When the sun travels through tiny ice crystals in the atmosphere you tend to see this effect," she says, "but the sun has to be high in the sky -- at least 58 degrees."
Circumhorizontal arcs most commonly occur in cirrus clouds but only when they're aligned horizontally.
"You're more likely to see this type of rainbow during the summer here in North America," Dayna says. "But in places like Europe, the arcs are much rarer."