by Judith Curry
On Tuesday, snowfall of just over 2 inches shut down metropolitan Atlanta’s roads, schools, churches, government offices and businesses. Thousands of flights were cancelled at Hartsfield-Jackson International Airport. More than 2,000 school children were separated from their parents, and spent the night in buses, police stations, or classrooms. – Politico
I am writing this post at home, on Thursday afternoon. I am at home since Georgia Tech has been closed since 1:30 p.m. on Tuesday – closed along with pretty much all of Atlanta.
Stories abound on Facebook and Twitter of massive standstill/gridlock on the streets of Atlanta, of 30+ car pileups, a mother giving birth in a car, a mother and toddler stranded on a highway for 20+ hours (out of gas, cell phone dead, no water and no blankets), parents separated from their children who were stranded at school or on school buses, etc. From my perch on W. Peachtree Street, from noon on Tues the 4 lanes of traffic was bumper-to-bumper, with continually wailing sirens of ambulances that could make no progress. By the next morning, and all day Wed, there wasn’t a car anywhere on the street.
So, how did it happen that one of the largest metropolitan areas in the U.S. was brought to a standstill by a few snow flurries?
The meteorology of this particular storm is discussed by Brian Norcross at Weather Underground:
Here’s the sequence: the initial snow melts due to the warm ground (55 to 60 in Atlanta on Sunday); the cold air freezes that water into a coating of ice (temperatures dropped through the 20s all afternoon); the road gets slipperier as the snow gets compressed onto the ice and/or melts due to the traffic (another 2” of snow fell after the initial melt); people see the snow, freak out (with good reason), and all leave work at once.
The meteorologists at the National Weather Service in Atlanta analyzed the weather pattern and the computer models quite well. Their discussions were clear enough in the days before the storm. It was a challenging forecast because Atlanta was on the northern edge of the snow, but the discussion of snow and a cold wind were always there. The day before the event, they had a Winter Storm Watch in effect for the city. They lowered it that night to a Winter Weather Advisory, a critical mistake in hindsight, and then put up the Winter Storm Warning in the middle of the night before the snow. So, it wasn’t perfect, but there was plenty of clear discussion of the possibility of a few inches of snow along with bitter cold temperatures.
Decision making under weather uncertainty
The rain/snow demarcation was a tough call, as it often is with temperatures right around freezing. It seems that the forecasts were good enough to have triggered a response prior to the onset of the storm.
Excerpts from the Weather Underground article:
To hear the public officials tell it, they were caught off-guard by the storm, so somewhere in that communications system there was a serious disconnect. The decision-makers either didn’t get the message, or more likely, didn’t have appropriate action plans, which the threatening forecast would have triggered.
A major city, along with the state in this case, in spite of direct communications with the National Weather Service, is unable to put the pieces together to understand the RISK to their citizens. Risk implies uncertainty, and understanding it is at the heart of decision-making. Let’s say the chance of the storm producing 3 inches of snow was 30% on Monday, which sounds about right. The Georgia decision-makers didn’t understand that a 30% risk of a cataclysm requires major affirmative action. You can’t wait for a guarantee.
How about a 20% chance of tens of thousand of people being stranded on the highway in freezing temperatures? Is that enough for a governor or mayor to make the decision to tell people to stay home? It’s not easy, but it’s not rocket science. Mostly, you have to understand the ingredients that have to come together to create a disaster in your city. (See formula above.)
Somewhere and somehow somebody has got to take the lead on closing the threat-understanding gap between forecasters, decision-makers, and the public. It’s not simple because of the division of responsibilities between various federal, state, and local agencies in a disaster. But, we’ve seen too many instances where good-enough weather forecasts have lead to bad decisions and poor public communications. The issue is partly science, which we should be able to solve with an organized effort by the National Weather Service, FEMA, and others.
The knives are out and the blame game has begun. GA governor Nathan Deal speaks on CNN [here]. He basically blames the National Weather Service, and then says he doesn’t blame anyone. He says “Mother nature has a mind of its own and does what it is going to do.”
The WeatherUnderground reports:
Georgia Governor Nathan Deal threw the National Weather Service under the bus – going so far as to say that local TV weather people made more accurate forecasts – but his statement shows a complete misunderstanding of the role of the NWS forecasters and the role of emergency decision-makers, including himself. The meteorologists make the weather forecasts, the emergency managers and decision-makers at cities, counties, states, and school boards are supposed to understand the impact of the weather, direct the government response, and communicate recommended actions to the public. Shockingly, the governor and the Atlanta mayor didn’t see that as their responsibility.
But there’s another big problem, which the Georgia governor articulated very well in his news conference. He was more afraid to be wrong in closing down the city, than he was of people being stranded in their cars. Until we can develop a system that keeps politics out of it and lets science and good judgment drive the decision-making bus, this kind of thing is going to keep happening.
Mayor Mitch Landrieu in New Orleans understood this process and closed down the city in advance of the ice that was forecast there. That wasn’t a guarantee either, but the RISK was sufficient that he made the hard and right decision.
Ah . . . so the kind of risk management that elected officials are good at is political risk management. What are the political downsides of making proactive decisions, and then the weather event fails to materialize? Two such examples come immediately to my mind:
- Does anyone recall the pre-emptive closing of federal offices in Washington DC last April, owing to a forecast of snow? I remember this, since I was in DC for congressional testimony (a tweet at 2 a.m. told me the Hearing was cancelled). Well, it rained in DC (didn’t snow). A bunch of flights into and out of DC were cancelled (including mine), but other than that I think the consequences of this pre-emptive closing were pretty minor, and that the right call was made by the government officials.
- Another example with a more complex outcome was the evacuation of Houston in 2005 in anticipation of Hurricane Rita. Following on the heels of Hurricane Katrina, sensitivity was high. Rita weakened and turned north, having almost no impact on Houston. Several people died in evacuation traffic accidents.
In recent decades, Atlanta gets a major ice/snow event every 4-5 years or so. Not frequent enough to justify a battalion of snow plows and salt spreaders. Why is Atlanta so vulnerable?
The Politico has a superb article entitled The day we lost Atlanta: How 2 lousy inches of snow paralyzed a metro area of 6 million. Excerpts:
What happened in Atlanta this week is not a matter of Southerners blindsided by unpredictable weather. More than any event I’ve witnessed in two decades of living in and writing about this city, this snowstorm underscores the horrible history of suburban sprawl in the United States and the bad political decisions that drive it. It tells us something not just about what’s wrong with one city in America today but what can happen when disaster strikes many places across the country. As with famines in foreign lands, it’s important to understand: It’s not an act of nature or God—this fiasco is manmade from start to finish.
The key problem is Atlanta’s transportation system. The system is primarily one of highways, with less than 10% of the greater metropolitan population actually living in the city of Atlanta, but a large number of them work in the city of Atlanta. Public transportation is rather minimal. MARTA (the Metropolitan Atlanta Rapid Transit Authority) consists of buses (which invariably I see to be nearly empty) and a train system that serves only a very limited region. Expansion of the the train system is mired in politics, including racial politics.
The Politico article sums it up this way:
As a Walking Dead fan, I appreciate all those jokes on social media, but as an Atlantan, I’m concerned that this storm revealed just how unprepared we are in case of real disaster. If Atlanta, the region, wants to get serious about public safety, its mayors, county officials, and state officials will need to start practicing regionalism instead of paying lip service to it. And whether threatened by a dangerous pandemic, a major catastrophe, or just two inches of snow, we need to have ways to get around—and out of—the city other than by car.
Personally, I manage Atlanta’s traffic problem in the following way. I live in Midtown, less than a mile away from Georgia Tech and in walking distance of restaurants and grocery and other stores. I use the car on the weekends to get out of Atlanta.
American Meteorological Society annual meeting
The annual meeting of the American Meteorological Society is being held in Atlanta starting this weekend [link]. This week’s disaster is a counterpoint to the theme of the meeting, which is Extreme Weather – Climate and the Built Environment: New Perspectives and Tools. This theme was selected by AMS President Marshall Shepherd, who is Professor at the University of Georgia. I will be attending the meeting Mon through Wed.
These two statements from the Weather Underground article sum up the situation IMO:
Somewhere and somehow somebody has got to take the lead on closing the threat-understanding gap between forecasters, decision-makers, and the public.
But this isn’t going to help unless you have an action plan that is developed prior to the event trigger:
. . .or more likely, didn’t have appropriate action plans, which the threatening forecast would have triggered.