NEW YORK -- Meteorologists, news media, homeowners and government officials aren't the only ones closely tracking the mega-storm roaring up the East Coast . Stock investors are watching, too.

The reason: Big storms like Sandy aren't just weather events, they are financial events, too.

Violent weather causes property damage caused by wind, rain, flooding, downed trees and power outages. Early damage estimates for Sandy are roughly $5 billion, according to Bloomberg News, citing data from Kinetic Analysis. Nasty storms also spur spending by consumers gearing up for the storm, as well as after the storm, when money is spent to restore damaged property to pre-storm condition.

As a result, many stocks are moved by a storm's potential impact. Some, such as shares of home-improvement retailers and makers of gasoline-powered generators, benefit - at least in the short term. Other stocks often take an early hit, such as property/casualty insurers that have to pay out still-unknown amounts of damage claims to policyholders.

"When this type of storm approaches the U.S., you typically see interest in stocks that tend to have an uptick in sales from storm-related preparation or clean-up," says Paul Hickey, co-founder of Bespoke Investment Group.

Hickey calls stocks that move the most "Hurricane Stocks."

The impact of a storm from a money standpoint is typically felt in three stages. First comes the pre-storm spending spree, when homeowners shell out cash for supplies needed to survive and ride out the storm. They buy generators, water, candles, non-perishable foods, flashlights and batteries. During the storm, people in its path hunker down, and traffic to retail outlets dwindles. Stage three encompasses the days and weeks after the storm, when clean-up and rebuilding begin. It's also the time when insurance companies do what they do: pay out claims to get homeowners and businesses back on their feet.

Here are some "Hurricane Stocks" to watch:

• Home improvement retailers. Home Depot (HD) and Lowe's (LOW) are two of the go-to stores when damaging winds, torrential rains and flooding are bearing down on homeowners. Big box stores like Costco (COST) that sell pretty much everything are also in play. They all sell the stuff that can stave off disaster. They sell sump pumps that keep basements dry. They sell generators that keep the power on when the electricity goes out. They sell plywood that protects windows from glass-shattering wind.

Home-improvement retailers also sell things that help homeowners put their homes back together once the storm has passed. They sell pumps to drain flooded basements, vacuums to suck up water, and power tools to remove fallen trees and limbs.

Friday's performance: Home Depot actually fell 0.7% to $60.04 and Lowe's declined 1.4% to $31.36. The home-improvement sector has been one of the market's best performers in 2012 as housing recovers. But they have been victims of profit taking in recent sessions due to a surprise drop in September existing home sales announced Friday. Costco was up 0.3% to $96.94..

• Generator makers. When the power goes out, gassed-up generators are turned on to keep the lights on, sump pumps pumping and refrigerators cold. One pure play is generator maker Generac (GNRC). Another is Briggs and Stratton (BGG), which in addition to generators also makes lawn mowers and snowblowers.

Friday's performance: Generac rallied 2.9% to $28.33, while Briggs rose 2.2% to $19.03.

• Property and casualty insurers. When the roof blows off, windows shatter or a tree falls and crushes the garage, it is the job of home insurers, such as Allstate, Travelers and Chubb, to pay up. So the knee-jerk reaction is for investors to sell these stocks as a storm makes news. But since most homeowner policies don't cover water damage caused by rising water, and given that a bad storm with big insurance payouts often leads to higher future premiums, home insurance stocks typically don't fall as much or fall as long as logic would suggest, says Meyer Shields, an insurance analyst at Stifel, Nicolaus.

"Most of the time the stocks snap back because it turns out to be not so bad, or it is bad enough so there is increased pricing power for the insurers," Shields says.

Insurers and re-insurers have also benefited from a year largely devoid of major natural disasters, which means they are in good financial shape to deal with whatever this storm has in store, Shields says. And while $5 billion in insured losses sounds like a lot, it pales in comparison to the insured losses of $62.2 billion incurred after Katrina, according to MunichRe. Last year's Hurricane Irene had insured losses of $5.6 billion.

Property/casualty insurers have their own insurance from so-called re-insurers to protect themselves from catastrophic financial losses due to massive payouts to policyholders, says Tom Larsen, senior vice president at Eqecat, a risk modeling firm. That softens the financial hit, he says.

Friday's performance: Chubb fell 1.8% to $77.96, Allstate declined 0.9% to $40.15 and Travelers lost 0.8% to $71.56.

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