As many as 50 million Americans living in the Northeast Corridor from Boston to Washington are bracing for the Frankenstorm, the combination of Hurricane Sandy, high tide and a nor’easter, which is likely to create storm surges of up to 11 feet in places that do not normally contend with them. Manhattan, for example. Or Atlantic City. Or Long Island’s south shore. Or Long Island’s NORTH shore, simultaneously. The National Hurricane Center describes it as a “life-threatening” storm surge. The shallowness of the water near the coast will make the storm surge higher, especially in and around the New York Harbor area.

Over 450,000 residents in low-lying areas have been told to evacuate, in New York, New Jersey and Delaware. Over 7,000 flights into and out of the region have been cancelled. Six states and the District of Columbia have declared emergencies. 540 miles of coastline will be affected, a testament to the sheer size of the weather event. The New York Stock Exchange and NASDAQ are closed today, as is the New York City transit system, New Jersey Transit, and SEPTA in Pennsylvania. All non-essential federal offices are closed as well.

There are also political implications. Maryland shut down early voting. In Virginia, Senate candidate Tim Kaine is asking his supporters to pull up all their yard signs, lest they turn into projectiles with the high winds.

First and foremost, we have a dangerous event that hopefully will cause no loss of life and the minimum possible damage. But when that stock exchange reopens, expect the market to dip. And the near-term result for the Northeast will probably be a continuation of the mysterious economic collapse there. In the near term, hurricanes can actually increase investment, as things need to get rebuilt. But the overall impact is pretty negative. Businesses shut down and some of them cannot restart right away. Construction is pulled forward but taken from other sources. And there are the potential insurance company losses, and associated impact. And where are most of those insurance companies headquartered? Why, the Northeast. All told, you’d rather not have a superstorm in your backyard, from an economic or any other standpoint.

But weather patterns like these will continue in an era of climate change, and at some point you have to stop calling them “once in a lifetime” events and start accounting for them, unless you’re prepared to mitigate the warming of the planet. That’s the choice, not between action and inaction. There’s a cost to inaction, and right now it’s hovering off the Atlantic coast.

Keep checking the National Hurricane Center and Reuters for updates.