If you are looking for the best pictures of the ash plume flowing away from Iceland, then check out the NASA page [LINK].
Air traffic has been pretty badly impacted by the safety precautions, with a blanket ban on flights over much of northern Europe over the past five days. Things look to be getting back on track now, with the UK, France, and Germany opening their airspace starting today [LINK].
A troubling aspect of the ban on air traffic is a backlash against it [LINK]. Apparently there are a number of voices saying that grounding the flights is too cautions, including some airlines. These dissenters say that the precautions aren't based on this volcanic eruption, but on "theoretical" approach.
This line of thinking strikes a familiar chord, I think. It seems that there is a general pattern for science-based decisions, which tend toward being conservative, to be questioned by interested parties. Of course, in this case "interested parties" is a euphemism for people/corporations/industries/governments who have a financial or personal stake in the situation. The usual argument goes something like, these scientists are overly cautious (or alarmist) and the problem isn't that bad, and we should be making decisions based on what is really happening and not what some fancy computer model says.
Let us be quite honest in saying that the science-based findings will be conservative. Decision making based on science follows that. This is best summed up by the old phrase, "better safe than sorry." I think this is the right way to go. There are times when calculated risk is the right approach, but when the choice is between people perchance dying in plane crashes (and airlines making tons of money) or people NOT DYING but being stuck somewhere for a couple of days (and airlines losing some money), what is the right approach? Well, I am betting that there would certainly be some questions if planes started falling out of the sky. Better safe than sorry.
Another aspect of this story is that the decision-making process would certainly be better served with better real-time data. There's no doubt that if we had better in situ observations of the volcanic ash plume, then we would have a better idea of whether it would be safe for airplanes to fly. But guess what? There's really no money for these kinds of observations. Not in Europe and not in the USA. Sure, you can turn to the NASA satellites and get a lot of information. But the real-time information that can be gleaned from the satellites is limited, both because of the satellite coverage and technology, and also because of limited personnel who have the ability to analyze the data. I'm guessing a good amount of real science will come from this eruption, but it will take months (and years) to be done. Better observations could be collected by using balloons, mobile observing platforms, and aircraft. These all require the proverbial boots on the ground. There have to be scientists/technicians on the ready, with the equipment ready to go, a way to get to the site, and personnel to ingest the data and provide analysis to decision-makers. There's no doubt the capabilities exist, and there are scientists who would be willing to do the work (and excited to do it), but there aren't usually resources for that kind of science.
So for those who say that we shouldn't rely on models and statistics for decision-making, I think this is a false dichotomy. It is either that or nothing at this point, but the better way to go is to choose both models and statistics along with real-time observations. I'd also be willing to wager that many of those on that side of the debate would not want to put the money on the table for the kinds of observational networks and responses that they are calling for. In the end, isn't the existence of the risk enough to warrant a response? Isn't it better to be safe than sorry? Given the available resources and the collected knowledge about the risk, I can not see any other recourse.