What is the Hindenburg Omen?

(CANVAS STAFF REPORTS) - Is the stock market destined for a crash?

According to an indicator known as the "Hindenburg Omen," criteria are lining up to make a crash more plausible. The scenario has some market watchers wondering if they'll soon hear shouts from Wall Street.

"We've never had a heavy sell-off without a Hindenburg Omen, but we've had Hindenburg Omens without a sell-off," Art Cashin, director of floor operations at UBS Financial Services, told CNBC earlier this month. "It's a bit of a warning ’ it isn't confirmed, but we will know in the next three or four weeks."

Several factors that measure the underlying conditions of the stock market must line up to add credibility to the prediction, which is named after the fiery crash of the German airship in 1937.

The complex criteria for the omen are focused on the level of uncertainty within the New York Stock Exchange, such as a lack of conviction among investors.

More specifically, the probability is created by monitoring the number of securities that form new 52-week highs relative to the number of securities that form new 52-week lows. The number of securities must be abnormally large, according to factoidz.com .

This criterion is met when both numbers are greater than 2.2 percent of the total number of issues that trade on the NYSE for that specific day, according to the factoidz.com .

The "Hindenburg Omen" has been trigger twice in August prompting the Omen's creator, Jim Miekka, to exit the market, reported The Wall Street Journal . "I'm taking it seriously and I'm fully out of the market now," Miekka, a blind mathematician, said to the newspaper.

How credible is the prediction? CNBC reported that the scenario occurred seven times in 2008, the year the economy went into a tailspin.

But not all experts are convinced we will see a crash in September.

"The Hindenburg Omen is index specific to the NYSE with seemingly exact requirements. ’ This type of exactitude is often a result of statistical curve-fitting and this signals caution. It's what I call a prima-donna indicator rather than a robust analysis tool," said Daryl Guppy, CEO of Guppytraders.com , told CNBC .