-- Alex Iwashyna didn't realize how many of her neighbors in Richmond, Va., had backup generators until her own family bought one in the dark days after Hurricane Irene. As she endured the drone of a combustion engine in her backyard, she noticed the same steady noise from neighbors' homes.

"I mean we joke about preparing for the apocalypse and stuff," Iwashyna said. "We've had an earthquake, a hurricane and a wildfire in Virginia ... it would have never occurred to me to get one until we lost power for that amount of time."

Homeowners around the nation have endured a nasty run of power-disrupting storms, and sales of portable power generators have been brisk, industry officials say. The "big box" stores such as Lowes and Wal-Mart did not release sales information, but according to one manufacturer, Briggs & Stratton Corp., Irene led to a spike in sales. While things have slowed since then, "we are continuing to see an uptick in demand," said Briggs spokeswoman Laura Timm.

In some places, the drone of generators is becoming as common during blackouts as lawnmowers are on summer Saturdays.

"I think we've gotten into a pattern of more severe weather events, whether it's snow or ice or rain or wind, you're just losing power," said Kris Kiser, who heads the Outdoor Power Equipment Institute, a trade group. "And I think people are more comfortable now with, `Hey, my neighbor has this generator and maybe I should try it next year.'"

In this year alone, a snowstorm crippled Washington, D.C.; Joplin, Mo., was devastated by a tornado; record-high water levels created havoc along the lower Mississippi from Missouri to Louisiana; and Texas was ravaged by wildfires. The insurance company Munich Re counted 98 natural disasters in the United States in the first six months of 2011, about double the average of the 1990s.

A lot of this extreme weather snaps power lines. Irene knocked out power to more than 9 million customers along the East Coast. A big snowstorm in the bustling Northeast corridor can easily cut power to more than 100,000. The recent wildfires interrupted power to several thousand. And it's not just storms that cause blackouts; investigators are looking into whether a utility worker doing a minor repair job led to roughly 6 million customers in Arizona, California and Mexico losing power this month.

As the U.S. electrical grid ages, the number of power outages affecting more than 50,000 customers more than doubled between 2005 and 2009 when compared to the previous five-year period, according to Massoud Amin, director of the Technological Leadership Institute at the University of Minnesota.

Enter the generator.

In Trumbull, Conn., Debi Norton was without power for a day and waiting in line at Home Depot to buy ice when she overheard a town official say that Irene had hit her neighborhood so hard that electricity would not be restored until that weekend.

"I said, `Four more days without power?' And I saw the generators lined up on pallets, and I said, `You know what? I can do this.'"

Norton spent around $600 on one of the last portable generators left in the store. That's a typical price, though portable generators can run to more than $1,000 depending on power and features. Larger "standby" generators that run on propane or natural gas can cost much more.

A generator with enough juice can handle a refrigerator, a furnace, lights and more. Norton not only kept her food from spoiling but plugged in her computer to play DVDs for her son. Iwashyna used some of her power to run her trash compactor.

Though unsuitable for apartment dwellers because of the exhaust, today's compact units are more family-friendly than the rumbling machines of yesteryear. Some start with a key rather than a pull cord. Honda claims its quieter generators are "no louder than normal speech."

Of course, many generators are louder than that.

"The noise is mind-numbing ... in the whole neighborhood, you can hear them," Norton said. "It seemed like every third house pretty much had a generator, or got one."

In one extreme case of generator stress during the Southwest's recent blackout, a 45-year-old Orange County, Calif., man was arrested after the noise from a neighbor's generator allegedly prompted him to beat the neighbor with a flashlight.

Other neighbors complain of the smell of burning fuel.

In Richmond, Iwashyna, a mother of two who blogs at lateenough.com, worried about whether the noise would bug her neighbors.

"That was one of my Facebook and Twitter questions to my friends: What is the etiquette?" Iwashyna said. "We're in the city but we have a yard and we're pretty close to our neighbors."

She and her husband turned off their generator at night. Norton turned her machine off periodically so she and her neighbors could get a break. Norton also performed one other act of gracious generator etiquette when she allowed her neighbor to run a cord to his refrigerator.

Despite the noise, Norton is happy with the generator. It gave her peace of mind caring for her son and she was able to enjoy hot coffee.

Some climate scientists say that extreme storms are increasingly likely, partly because of global warming. And forecasters say the Pacific Ocean climate phenomenon La Nina, which contributed to extreme weather around the globe during the first half of this year, has re-emerged and is expected to gradually strengthen and continue into winter.

"I'm sure I'm going to use it again," Norton said of her generator. "It's not a matter of if. It's a matter of when."