When one of BP's (NYSE: BP) oil rigs exploded last spring, the words "Deepwater Horizon" became part of our vernacular overnight. Coverage of the spill was ubiquitous. News channels gave hourly status updates. Newspapers speculated on the cost of damage. You could not possibly have avoided hearing about the spill.

Still, with this situation clear as daylight to anyone not living in a cave, savvy investors were able to swoop in and make a killing on investments tied to the spill.

Today, another catastrophe has created similar opportunities for investors -- only this time, nobody seems to be paying attention.

How smart investors played the oil spill
But before we get into today's opportunity, let's take a quick look at how smart investors profited in the wake of the Gulf oil spill.

Most investors reacted in their predictable way to the rig explosion: They freaked out. Shares of BP and Transocean (NYSE: RIG), the respective owners of the well and the rig, plummeted, and so did any company even remotely related to offshore oil. Drillers, rig servicers, and even major oil companies saw their shares sell off.

As those investors fled, the special situation investors swooped in. BP itself might have been a risky investment, but rigger Atwood Oceanics (NYSE: ATW), which owned but a single rig in the Gulf of Mexico (and its least valuable rig at that), nonetheless saw its share price drop 35%, offering opportunistic investors a dirt cheap buy price.

I pitched rig operator Noble (NYSE: NE) to some other analysts at The Motley Fool since the stock was trading for roughly the value of its rigs at the time, and was one of only two riggers with more cash on its books than debt. Motley Fool Special Ops bought shares of Ensco (NYSE: ESV), the other rig company with net cash, for less than the company's tangible book value. Noble and Ensco are up 59% and 57%, respectively, from their post-spill lows.

Today's opportunity
Thanks to torrential rains caused by a La Nina weather pattern, Australia has been hit with its worst floods in half a century. Floodwaters now cover a land area equivalent to that of France and Germany combined. Think about that for a moment.

The Australian flood is not unlike the Gulf oil spill: It's a big deal to local industry. The state of Queensland, where the floods are worst, is a major exporter of sugar and wheat, and Australia as a whole accounts for two-thirds of the world's supply of coked coal. The floods' effect on crops and infrastructure has been widespread, and when all is said and done, will likely be devastating in many areas.

Ways to ride the rising waters
After the Deepwater Horizon ordeal, emotional investors fled drilling-related stocks, creating opportunities for more rational investors. My initial instinct in looking for investment opportunities created by the Queensland flood is to play this "not-as-bad-as-it-seems" card, looking to buy stocks that had been oversold by fear-inspired sellers. So far, however, such a serious sell-off has not taken place.

Instead, the flood has created investment opportunities in other ways. Just as many companies are seeing the natural disaster take a toll on their businesses, others are poised to benefit from the rising waters.

Bet on the smaller suppliers
Rio Tinto
(NYSE: RIO), the world's third-largest mining company, is one of the former. The company resorted to declaring force majeure (a legal clause permitting missed shipments because of circumstances beyond a company's control) for aluminum supplies out of its Queensland facility, because the flood has cut off access to local infrastructure, including roads and railways. It seems that BHP Billiton (NYSE: BHP), which has seen coal output drop 30% and recently said operations will be hit for at least six more months, will likely have to follow suit.

Rio Tinto's and BHP Billiton's struggles are good news for smaller competitors still in operation. One company that stands to benefit directly from Rio Tinto's force majeure invocation in Alumina, an Australian company that mines bauxite, refines alumina, and smelters aluminum -- but unlike Rio Tinto, whose smelter plants are in Queensland, Alumina's two plants are in Victoria, south of the worst of the flooding.

Bet on the rebuilders
The havoc the flood has wreaked on Queensland's physical infrastructure is ruinous -- and someone will have to fix it.

Australian infrastructure companies are pained, I'm sure, watching rains ravage part of their country, but they must also be licking their chops in anticipation of all the upcoming reconstruction work. Infrastructure firm Leighton Holdings (OTC BB: LGTHF), headquartered in Sydney and with operations in civil engineering and construction is particularly well-positioned. So is Cardno (OTC BB: COLDF), which consults on structural and environmental engineering projects and specializes in coastal, ocean, and marine infrastructures. The transportation of all the needed building materials and equipment will benefit Asciano (OTC BB: AANOF), which owns and operates several of the Australian ports and railroads through and over which supplies will be shipped.

Go where the opportunities are
If you like this style of investing -- seeking out fertile hunting grounds and making the most opportunistic picks -- you should check out Motley Fool Special Ops. Headed by special situations investment expert Tom Jacobs, the Special Ops team scours the globe for opportunistic investments. Special Ops will be soon opening to new members today for the first time since its launch. If you are interested in finding out more or receiving a video explaining three of Tom's favorite stock ideas, simple enter your email address in the box below.