Just how doomed are you?

Short Version: storm forecasts are pretty much on track for the US East Coast, including coastal GA/SC. Biggest tornado risk is Charleston SC area. But seriously, what are the odds this thing will kill you? Let’s crunch the numbers …

The big storm system sweeping across the US will reach the southeast coast this afternoon/evening. Here are the US Weather Prediction Center’s “Key Messages” in graphic form for this morning (link is here, it’s a good place for overviews if you don’t want the media hype about storm systems):

The severe thunderstorm/tornado risk across the southeast is “enhanced”, but the picture is a bit more complex than this simple graphic indicates. 

Bottom line: windy, stormy day, for GA coast and SC Lowcountry. The main squall line (QLCS) should pass the coast between 1 and 5 pm, and calm down overnight.The severe risk looks to increase south to north, with the more northern areas having a better chance for tornado activity than the south, but in any case not up to “surrender Dorothy” levels. Still, keep your weather radios and other warning devices handy, could be a busy day with alerts. The latest weather briefing from NWSFO Charleston (covers Darien, GA to north of Charleston, SC) is at this link. Briefings for other parts of the US are here.

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So, will this storm kill you? Should the schools and businesses close today? It’s a complex question. The discussion below focuses on the Savannah, GA area, but you get the idea for how it might work elsewhere. First let’s look at the statistics. Since we’re working with small numbers, let’s use the rate per 100,000 (100k) people, and average over the last decade (throwing out 2020 due to the pandemic, which skewed the statistics). A rate of 1/100k equates to a 0.001% chance. Your chances of being murdered in Savannah in most years are around 12/100k. (that’s about double the national average of 6/100k). Of course, your lifestyle has a lot to do with those chances. If you’re not a drug dealer or gang member your chances are a lot less than that. Which raises the question of how your actions influence the risk. But let’s just use the baseline risks. How does that compare with your chances of getting killed on Abercorn? It’s no secret that Savannah in particular and Georgia in general are notorious for bad drivers. In recent years Savannah has had a fatal car accident rate of about 16 per 100k, in 2017 that was second in the nation (Baton Rouge, Louisiana was number one at 23/100k)!

So that’s the context of the risk: murder at 12/100k, traffic accident 16 per 100k. How does severe weather compare? For the Savannah area, it’s about 0.1 in 100k. The national average is 0.3/100k. Put another way, your risk of being murdered by your fellow citizen in Savannah are 120 times higher than your risk of being murdered by this storm. Your chances of that idiot barreling down Abercorn and running the stop light killing you are even higher, 160 times higher than this storm!

So what does that mean with respect to closures? It’s a complex question that, surprisingly, really doesn’t involve risk directly as much as it does the perception of risk, logistics, and liability. Imagine how you would feel if the traffic accident rate were hyped as much as storms? If the TV advised you to download their app that warned you every time someone ran a traffic light? (oh, crap, hope I didn’t give anyone any ideas!) You’d be a nervous wreck. So people tend to worry about storm more even though the risk is less. However, it’s not that simple.

From a safety and logistics standpoint, the biggest issue with respect to school closures is not safety from the storm at school, it’s traffic safety getting to and from school.  Once at school students are probably more safe from severe weather than at home. Generally speaking, bus operations become dicey when sustained winds get over 35 mph, and gusts over 45 mph. So, looking at today’s weather in Savannah, operations would probably be fine this morning, but school would be letting out right in the projected worst of the storm, as the front sweeps through. How risky would that be? All things being equal, not that high. However, there are two aspects. First, any incident would likely involve multiple students and therefore would be heart-rending and, second, in today’s America, the liability (political and legal) would be huge.

There are other issues that should be considered such as the fact that public schools perform a vital social safety network in urban areas, in terms of providing meals to lower income students as well as what is effectively state sponsored child care. Those issues are (or should be) additional factors in the closure decision. Saying “we always err on the side of caution” is both foolish and often untrue, when secondary factors like that are not considered. As usual, this already long post would be even longer to fully explore those aspects, but I hope this gives you material for thinking about how complex this discussion can get, and how it’s not really only about weather and risk, but about lots of other issues like perception of risk, media hype, politics, and economics.