Survivable norms - February 21. 2012

As predicted, what fell last night (a respectable 1 to 1.5 inches) melted off most streets today. I walked Anya at school this morning (after creeping behind an SUV that was litterally sliding up to the curve), then holed up in the office. I didn't pay that much attention to the weather or road conditions, because I didn't have to.

I've been editing a map of New Orleans this last few days, getting down in detail what restaurants are open and closed. The last time I updated it was still very much in the aftermath of Hurricane Katrina, and when I went down for the initial fieldwork it was only a year after the storm hit. There was still a lot of wreckage and boarded up buildings, including a number of downtown hotels and other buildings that simply weren't open yet.

They don't get hardly any snow in New Orleans. The average low in January is 43°F, and in my lifetime (since 1965), now has fallen three times: 1989, 2004 and 2008. A seriously cold snap there is not quite as bad as the one killing the iguanas and pythons in South Florida, but I'm sure it does put a crimp in things.

We build for comfort in normal times, with a fallback to survival in worst imaginable times. And we base these two standards on what we know from experience (ours or others) or by comparison. This doesn't always work out—I think of the poor Lewis and Clark expedition, direly unprepared for a winter of near-constant rain at Fort Clatsop in what is now Oregon. Of course, they hadn't built up much of a civilizational groundwork under them either. But imagine a really extreme cold aberration in New Orleans, like a month below freezing and a week below zero—a "normal" winter in Minnesota. It would be a disaster with lots of deaths. Not to mention a terrible environmental and agricultural toll.

Which is part of what makes things like nuclear winter or oversize tsunamis or volcanic eruptions so terrifying to consider: they are beyond the survivable limits we have built our civilization on.