Twenty years ago last week, I stood outside a low cement building in Woods Hole, Massachusetts, on Cape Cod, and leaned into the 80 mph wind. Hurricane Bob had arrived, and a few hundred of us had piled into one of the more secure buildings in town to wait it out. Parents watched from inside as 10-year-olds like me strayed a few feet from the doors to experience the rare New England hurricane.

Afterward, I watched people canoe down flooded streets and carefully walked a bike path that had become home to boats tossed up from the bay below. Bob caused more than $500 million in damage to Massachusetts alone (closer to $800 million in today's dollars), and for now at least, Hurricane Irene is tracing a strikingly similar path. Current forecasts make it appear likely that the storm, now sporting 115 mph sustained winds, will hit North Carolina and then possibly cross Long Island on its way toward Connecticut, Rhode Island, and Massachusetts. It could pass very close to New York City itself, where low-lying areas could experience dangerous storm surges [pdf].

On its own, a hurricane clawing its way up the East Coast isn't particularly unusual, even if they do swing out to sea and lose power more often than not. But if Irene does hit the U.S. hard, it could add to a growing list of extreme weather events that have shaken the country -- and the world -- this year in ways we haven't seen before. The first half of 2011 has seen more billion-dollar weather disasters than in any other year. The National Climatic Data Center reports nine events -- from the tornadoes that hit Tuscaloosa, Alabama, and elsewhere, to the ongoing drought and wildfires in Texas -- that have exceeded $1 billion in damages, with a total cost of more than $35 billion. Over the last 31 years, there have been only 108 total such events.

One can shrug and chalk this up to chance, but there is increasing evidence that what we generally call extreme weather, from hotter and longer heat waves to bigger blizzards, could now be considered "normal." As the climate warms, droughts and storms of increasing severity may increase in frequency, thanks to changing weather patterns and the atmosphere's ability to hold more water vapor. This doesn't necessarily mean that Irene will have company in her path across New York and New England any time soon, but it could mean that the billion-dollar disaster trend will continue apace.

If Irene does follow her projected path and dump loads of rain on the mid-Atlantic and New England, a number of records will fall and add to 2011's extreme weather legacy. Both New York City and Philadelphia will most likely break their records for the wettest single month on record; for New York, the record dates back to 1882.

After Hurricane Bob passed in 1991, my family's small cottage in Woods Hole was without power for six days. I remember not minding the cold showers, though; the hurricane had been fun, something new, and 10-year-old me couldn't wait for the next chance to see waves three times my size crashing over sea walls. Today, after watching the country swelter, burn, and flood for the past year, I'd just as soon take a pass.

Image: Tropical storm wind speed probabilities for Hurricane Irene via NOAA