Hurricane uncertainties – a personal case study

I am glad to write to you that I had some relaxed holidays during August in the Azores.  For some of you who are unfamiliar with this little place, Azores is mostly known by its natural landscape, moderate climate and relaxed inhabitants. According with a rating done by the Dutch National Geographic, Azores was considered in 2016 the top place to visit (

Anyway, on our way way back there was some news/warning that the Azores would be affected by the Hurricane Gaston. Luckily for me and my family it was going to hit on Saturday, two days after we were going to fly back to Germany (by the way I am originally from the Azores). Regarding natural disasters, Azores is often associated with Earthquakes. Truth is that they have also been hit in the past by few extreme weather events (see for instance Hurricane Gordon, Helene or Alex).

Well given that QUICS focuses on the topic of uncertainty, it does seem appropriate to show you some of the forecasts issued by the US National Hurricane Center for the recent Gaston Hurricane. It shows some of the practical aspects of communicating uncertainty to non-experts. Weather forecasting as we all know is highly uncertain, and hurricane forecasting is not an exception. In particular, I have chosen two examples: the first displays uncertainties of paths, and the second uncertainty of intensity.

Figure 1: Coastal Watches/Warnings and 5-Day Track Forecast Cone, Hurricane GASTON Advisory #035, 5:00 AM EDT Wed August 31, 2016 (See this NHC page for current map)

Figure 1 shows you the 5 day track forecast issued on the 31st of August superimposed with the one issued on 2nd of September. The black line shows the forecast track on the 31st and the large blue area is the cone of uncertainty in the future track on the 31st. The smaller blue area is the cone of uncertainty on the 2nd. The cone of uncertainty is based on historical data, 60 to 70% of all historical data indicate that the storm center will remain within the cone for the days following the forecast.

Figure 2: Tropical Storm Force Wind Speed Probabilities, for 5 days from 2nd of September.

The second example deals with wind intensity. Indeed, this is the main issue why hurricane forecasts are issued (see Figure 2 or a current graphic on the NHC site). Winds can reach destructive speeds and are responsible for increasing the wave height considerably (e.g. during hurricane Alex waves up to 14 meters were recorded at high sea). Figure 2 shows the cumulative probability that wind speeds of at least 39 mph will occur during a 120 hour period.  Maps of shorter time periods can be seen on the NHC site (click the different durations or loop in the top right), each graphic provides cumulative probabilities the that wind speeds of at least 39 mph will occur during cumulative time periods at each specific point on the map. Unlike the previous map, here it is possible to compare how intensities are expected to evolve during the five day forecast.

As I mentioned before Azores inhabitants tend to be quite relaxed, and indeed this time it was not too bad. The Hurricane went down to a tropical storm and it did not cause too much damages. A happy ending!


Since I started with telling you about our holidays in the Azores, it is well suited to finish it with a picture we took. To conclude let me just write that the Azores is also populated with plenty of black and white cows (while some will say this last sentence is useless others may find it useful for understanding the bigger picture).

All the best!

Jorge Leandro (TU Munich and University of Coimbra)

Hurricane uncertainties – a personal case study

SPN 8: the real stuff!

Last week, we’ve successfully organised the 8th edition of the Sewer Processes and Networks conference in Rotterdam, the Netherlands on behalf of the IWA working group on Sewer Systems and Processes (SS&P WG). The conference took place on board of the SS Rotterdam, an excellent place to spend a few hours on the sun deck at the end of summer in Rotterdam.

SPN8 Group photo
SPN8 Group photo

Two of the QUICS promovenda, (Antonio Moreno Rodenas and Ambuj Sriwastava), one QUICS post-doc (Mathieu Lepot) and a number of QUICS supervisors (Simon Tait, Francois Clemens and Jeroen Langeveld) witnessed a conference with a lot of presentations about the real stuff: experimental work on sewer processes, either in labs or in the real world.  After a decade where modelling studies have been declared as the most convenient way to quickly publish the required amount of journal papers to obtain a PhD, the tide now seems to be turning towards obtaining real (new) knowledge on the most interesting part of integrated catchments: the sewer. Even though admitting studying sewer system dynamics may not be your best bet at your first date, there are a lot of very interesting research topics related to sewer processes, such as: climate change, CFD modelling, discharge patterns of pharmaceuticals, impacts of H2S on brains of sewer workers, spreading of antibiotic resistance via bacteria in sewer biofilms and sediments, monitoring and inspection techniques, asset management strategies, distributed temperature sensing, ground penetrating radar, aeration and H2S release at drop structures, methane formation, retrofitting urban areas with blue-green structures, gully pot cleaning and yes, also integrated approaches and the relevance of uncertainties in rain radar images for integrated catchment studies (thanks Antonio!).

In addition to the conference, we’ve organised a pre-conference workshop on ‘ lessons from failed research’ . All experienced researchers know that many research projects fail at least partly. However, it is very hard to find well documented results of failed research or negative results in literature. This is due to the ‘positive research bias’ of journals, that all want to publish positive results and implicitly train their reviewers and editors to reject less favourable outcomes. The workshop learned that there is a lot to learn from failed research and Richard Ashley and Francois Clemens now take the initiative to compose a review paper discussing how we can benefit from lessons from failed research. Those of you interested in sharing knowledge on this issue, please contact Richard via

Jeroen Langeveld, TU Delft

SPN 8: the real stuff!