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It seemed a little apocalyptic: Climate Case Study

By: Dr. Ricky Rood, 5:48 PM GMT on May 02, 2014

It seemed a little apocalyptic: Climate Case Study

When I heard that the train carrying crude oil had blown up in Lynchburg, VA yesterday (April 30, 2014), it felt a little apocalyptic. Lynchburg, VA is place that I remember fondly because as a kid riding around the country looking at Mail Pouch Tobacco barns, Lynchburg had this big billboard on the edge of town proclaiming it the home of Chapstick. (Here is a set of historical pictures from Lynchburg.)

The burning train in Lynchburg immediately brought to mind the Lac-Megantic Quebec disaster in July of 2013. There have been several train wrecks and fires in the last year. They are all carrying petroleum products. This is an issue that I mentioned in my blog on No Energy Policy and the Keystone Pipeline. It is, therefore, part of climate change and our response.

Earlier in the day I had been asked by my favorite climate policy friend whether or not there was any new information about climate change and tornadoes. The question was in response to the tornadoes in Arkansas, Mississippi and Alabama. My response was to steer away from attributing the tornadoes to climate change, especially if any public statements were to be made. The special circumstances that lead to tornadoes are complicated, and how tornadoes will change in our warming and moistening planet is far from certain. A likely change in the characteristics of tornadoes would be the timing of tornadoes, occurring, perhaps, earlier in the year. I said that if there was something to talk about policy wise, then it would be the quality of forecasts and warnings. Alas, even this is politicized, as Rep. Jim Bridenstine (R-OK) gave NOAA Director Dr. Kathryn Sullivan grief over forecast deficiencies and stated that NOAA was compromising weather forecasting by placing money in climate research rather than forecasting.

What did catch my climate sensor, however, was that rather than more Alabama tornadoes on the afternoon of April 29, 2014, there was more than 15 inches of rain in Pensacola, FL (NWS Historic Flash Flood). What struck me first was that all of this rain was not very far east of where the tornadoes had struck the day before. I immediately thought of the jet stream and the blogs I’ve written on the research about weather systems moving more slowly. There was all of this rain in Florida, and here in Colorado where I am, there has been a persistent and unpleasant north wind. In California, it’s hot, chronically dry, with unusual Santa Ana winds and wildfire. (More on Santa Ana winds)

With all of this I hunted down a weather map at the European Center for Medium-range Weather Forecasts, which I reproduce in this figure. This map is of North America and shows the sea level pressure and the wind speed (colors). The wind field is at an altitude about 1.5 km above sea level (850 hecto-Pascals (hPa), nice discussion of 850 hPa). I have marked the low, high, low pattern extending from the eastern half of the U.S. into the Atlantic Ocean. This is a distinct and unusual pattern that has been slow moving, perhaps pretty close to stuck.

Figure 1: Sea level pressure and 850 hPa wind speed (about 1.5 km above sea level) from ECMWF. See text for description.

I put a big red arrow crossing the coast at the Florida panhandle. This is where very moist air is flowing, persistently, into the East Coast of the U.S. This is the source of the water for the extreme rain. Here we have two important characteristics, the weather pattern is moving slowly, and moist and warm air resupplies water as it rains out of the atmosphere. I put another red arrow in the center of the continent, showing those north winds in Colorado. They’re just the other side of the low that caused the rain in Florida and Alabama. In the western side of the U.S. and Canada, there is a broad region of high pressure (dashed red arrow), which keeps California hot and dry and is also the condition that sets up Santa Ana winds.

Let’s return to Pensacola. The Pensacola News Journal has many stories and pictures of the flood. Here’s another story on the flood from the Tallahassee Democrat. Also I have learned about NWSMobile, which has many snippets about the flood along the Alabama – Florida shore. Here is an entry with rainfall totals that shows a total, at 7:40 AM on April 30, of 17.70 inches of rain in Pensacola. The pictures show collapsed roads, flooded cities and overwhelmed sewers.

Later in the day I got an email from a friend entitled “The near future is clear.” The first sentence is “We got about 8-10 inches of rain over the past day and a half.” This is up in Maryland. There is this amazing video in the Baltimore Sun of a road collapsing in Baltimore - you need to make it to about 1:18 in the video.

In my last blog I wrote about the impacts of climate change. One of the most robust signals that has already emerged as the climate warms is the increase of extreme precipitation events. For example Groisman et al. 2012 state that, “Analyses show that for the central U.S., a statistically significant redistribution in the spectra of intense precipitation days/events during the past decades has occurred. Moderately heavy precipitation events (within a 12.7–25.4 mm per day range) became less frequent compared to days and events with precipitation totals above 25.4 mm.” This observation is not limited to the Central U.S. or even the U.S.; it is a global observation. Figure 2 shows changes observed in the continental U.S.

Figure 2: From Jeff Master’s blog on 2011 extreme spring: Percent increase in the amount falling in heavy precipitation events (defined as the heaviest 1% of all daily events) from 1958 to 2007, for each region of the U.S. There are clear trends toward more very heavy precipitation events for the nation as a whole, and particularly in the Northeast and Midwest. Climate models predict that precipitation will increasingly fall in very heavy events, similar to the trend that has been observed over the past 50 years in the U.S. Image credit: United States Global Change Research Program. Figure updated from Groisman, P. Ya. et al., 2004: Contemporary changes of the hydrological cycle over the contiguous United States, trends derived from in situ observations. Journal of Hydrometeorology, 5(1), 64-85.

Anecdotally, in the problems that I work with on climate planning for cities, the issue that is most discussed is extreme rain and the impact on cities. The Duluth, Minnesota flood of 2012, caused by a slow moving weather system, overwhelmed the storm sewers and water management systems. The floods in Duluth and Pensacola demonstrate vulnerabilities. From the Glossary of the IPCC Working Group II vulnerability is defined as “The propensity or predisposition to be adversely affected. Vulnerability encompasses a variety of concepts including sensitivity or susceptibility to harm and lack of capacity to cope and adapt.” My colleagues and I find that people understand vulnerability, especially when made real to them by streets collapsing, municipal sewer plants overflowing, cars sliding into the abyss, buildings flooding and people suffering physical and financial harm. When this vulnerability aligns with observations, such as those, highlighted above, of increasing extreme precipitation, then the links between weather, climate and new types of risk become real. When the observations of change, the predictions of models, the relation between weather and climate, and the need to rebuild infrastructure to last for fifty years come together, then inclusion of climate change into planning and development becomes desirable and substantive.

The weather events of this week are part of our evolving climate. The extreme rains, the drought and fires are too closely aligned to what we expect from climate change to ignore. They provide us with examples of weather, climate, vulnerability and impacts. They demand our short-term and long-term response. Looking at the cars crashing into the ravine in Baltimore, we are reminded that neglect of infrastructure will become more vulnerable to extreme weather events. And, if weather events that are extreme relative to weather for which infrastructure is designed are becoming more frequent, then separation of climate, climate change and vulnerability into their own little cubbyholes of cause and effect denies how we are intertwined with our climate and climate change.


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The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.