The third time's a charm, they say.

For insurers, though, the third hurricane in almost as many weeks could herald an earnings hit. For Allstate (NYSE:ALL), Chubb (NYSE:CB), and St. Paul Travelers (NYSE:STA), unless the latest storm rides in like Ivan the Terrible, they'll soon find themselves strapped for cash.

Just last week, Bill Mann was noting that even though Florida was facing back-to-back hurricanes, Charley and Frances were not actually a cause for concern because the insurers had prepared themselves for such eventualities. The problem with Ivan, however, is that a third moderate hurricane, one that causes only another $3 to $10 billion in damage, leaves insurers with little ability to raise rates.

Indeed, after Charley and Frances, Allstate and State Farm estimated their combined losses at just $625 million after collections from the state catastrophe fund and private reinsurers, such as Berkshire Hathaway (NYSE:BRK.A, BRK.B). The state-sponsored programs shouldered some $3 billion of the estimated $7.4 billion that Charley caused.

Yet if Ivan is indeed terrible, and right now the storm is raging along as a Category 4 hurricane on the Saffir-Simpson Scale with maximum sustained winds of almost 150 mph, insurers will be able to plead their case for raising rates more easily to the state's regulators.

It also puts Florida insurance buyers in a jam. With hurricane season in full swing, insurers have stopped issuing new auto and homeowners policies. Allstate just started writing new car policies, and few have issued a new homeowners policy since Sept. 1, when the hurricane watch for Frances went into effect.

It was Hurricane Andrew in 1992 that changed the game in Florida. Following the devastating losses that amounted to more than $15 billion, 11 insurers went out of business. State legislators allowed insurers to add sizeable deductibles to homeowners policies and permitted fourfold premium increases in some cases. Rates are expected to go up 10% next year -- more than double the national average.

Still, with just the past two hurricanes, insurers have used up catastrophe funds they normally set aside for the entire third quarter, which is also the hurricane season. Ivan poses dilemmas for insurers in that too small of a hurricane does not let them raise rates enough and too big of one could have an impact on earnings. And that does not even account for the human toll.

Investors are eyeing insurers cautiously now, with Hartford (NYSE:HIG), Allstate, and St. Paul easing back anywhere from 2% to 5% over the past few days. Most analysts believe that aside from a temporary setback in earnings the insurers will be escaping the wrath of the hurricanes relatively unscathed.

That could present an opportunity to buy in on a market overreaction. Perhaps the storm clouds can still have a silver lining.

Fool contributor Rich Duprey notes that we're still eight hurricanes away from Hurricane Richard this year. He does not own any of the stocks mentioned in this article.