It's baaaaack: volcanic ash visits great uncertainty on parts of Europe

May 7,(U.K.) Times Online:

Ash-free Spain could become an emergency flight hub
Spain has been spared falls of ash from Iceland’s volcanoes for much of the past 40,000 years, according to research that suggests the country could serve Europe as an emergency flight hub in the event of another eruption. ...

May 8, 5:30 AM EDT, AFP:

Iceland ash clouds halts air travel in Spain, Portugal
MADRID — An ash cloud from an Icelandic volcano caused new disruption to air travel in Europe on Saturday with Spain shutting down 15 airports and Portugal cancelling 104 flights, authorities said. ...

Well, perhaps the wind pattern that took Iceland's volcanic ash cloud over Spain is a fluke. And the cloud is not expected to hang over Spain and Portugal for long.

According to a Wall Street Journal report filed at 8:35 AM EDT today, Spain's airport authority, Aena, announced that the flight restrictions will remain in place until by 6:00 PM local time. The WSJ also reported:

Eurocontrol, the pan-European air traffic control agency, said trans-Atlantic flights faced "substantial delays" as controllers sought to reroute traffic around a thin line of ash stretching south from Iceland to Portugal, with the potential to drift as far east as Barcelona and Marseilles, France. ...

Airlines reported that overnight trans-Atlantic flights saw delays of up to three hours as aircraft were rerouted north and south of buffer zones established around the plume under new rules drawn up after last month's six-day shutdown of much of northern Europe's airspace.

Westbound trans-Atlantic flights Saturday -— including to and from major hubs such as London Heathrow -- also faced delays as air-traffic controllers dealt with the reduction in available airspace.

A spokeswoman for British Airways PLC, one of the airlines most affected by the volcanic eruption, said the carrier was running its full schedule, although with delays.

"The schedule is going ahead as planned, but we are experiencing some delays, particularly over the North Atlantic," she said. She said some flights were being rerouted around the cloud, which leads to longer flight times. Where possible given safety constraints, flights may also be routed above the cloud, she said.

The delays are a substantial improvement over the blanket closure of airspace to all instrument-navigated flights that occurred last month. On May 4 a hastily arranged summit of transport ministers from the EU's 27 countries began hashing out plans to unify Europe's divided air-traffic-control networks, in the effort to prevent a repeat of last month's chaos.

Ironically, the summit occurred on a day that saw flights from Northern Ireland, the Irish Republic, and Scotland disrupted as a shift in the winds again brought ash from Eyjafjallajokull over northern Europe. Noel Dempsey, Republic of Ireland’s Transport Minister, was unable to attend the summit because of grounded Irish flights.

However, the summit made headway. The ministers committed to researching new ways of identifying and measuring radar-invisible ash clouds and legally defining safety standards for specific makes of jet engines and the airline industry as a whole.

As to how things stand now with the volcano, according to Canada's CBC:

Iceland's Institute of Earth Sciences said the volcano's plume has risen [last] week to nearly 5.5 kilometres following several large explosions. It said tremours emanating from the volcano have intensified since Sunday night [May 2] and the eruption that began April 14 shows no signs of ending.

Dymphna at Gates of Vienna left a comment this morning at my post about this year's Atlantic hurricane season, which meteorologists expect to be severe. She wrote in part:

Given that Iceland is so very far from the prevailing winds which form our weather disasters, I wonder if the current conditions (and the new eruptions expected) will eventually drift high enough to be carried far enough south to affect the coast of Africa, etc.

IIRC, ash has a cooling effect.

My answer to both comments is "wild card." The winds that have sent the ash cloud away from Iceland have been part of an unusual weather pattern -- the same one that caused the unusual frigid temperatures in Britain in early January. Of Iceland's eight volcanic eruptions in the past 40 years, only the present one at Eyjafjallajokull was followed by winds blowing southeast toward northern Europe.

And it was the unusual wind pattern, combined with a high pressure system or what meteorologists also call a "blocking high," that kept the ash cloud pretty much stationary for about six days over much of Britain.

So, who knows at this point how the winds are going to be blowing a month from now? All that's known is that as long as the volcano's magma finds ice to fuel its ash eruptions the airlines, air passengers, governments, and businesses that use air cargo have to plan to be very flexible.

Once the magma burns through all the ice, then it doesn't matter how the wind blows; the ash cloud will disappear even if the volcano keeps erupting.

As to the cooling effect of volcanic ash on the weather, the extent of depends on more than one factor. In my April 15 post I featured an article on volcanic ash published by The New York Times, dated April 15 and written by Henry Fountain. Here I'll excerpt just the sentences that pertain to the cooling issue. ("Dr Burton" refers to Bill Burton, associate director of the
United States Geological Survey’s volcano hazards program). Emphasis throughout mine:

"While an on-again, off-again eruption probably would not have much effect on air travel over the long term, it could affect the weather in Northern Europe, said Richard Wunderman, a volcanologist with the Smithsonian Institution in Washington. The volcanic plume contains a lot of sulfur, he said, “that can become an aerosol up there that hangs around a long time reflecting sunlight.”

“It’s not enough that it’s probably going to be cooling the whole climate,” he added. But on a regional basis it could create what is called volcano weather, with smoglike conditions.

Unlike huge volcanic blasts like that at Mount Pinatubo in the Philippines in 1991, the eruption in southern Iceland began slowly about a month ago, with a series of fissures on the side of the volcano and what volcanologists call fire fountaining, the spewing of hot magma through vents. Dr. Burton said that it was only when the magma found a new route through the volcano earlier this week — shifting to the summit, directly under the glacial ice — that the ash-rich eruption began.
[...]
Dr. Burton said the eruption was low on a measure of power called the volcanic explosivity index — certainly nowhere near Pinatubo, which rated a 6 on the 1 to 8 scale, or the 1980 explosive eruption of Mount St. Helens in Washington State, which rated a 5.

Pinatubo spewed so much ash, dust and aerosol particles into the atmosphere that it lowered average air temperatures worldwide for several years, as the particles blocked some sunlight from reaching the Earth. So far the Icelandic eruption has spewed far less material, and its location, in the high latitudes, also reduces its global impact. “The closer to the poles, the less effect it is likely to have,” Dr. Burton said.

Of course the situation couldn't be coming at a worse time in Europe given the convergence of the recession, Greece's debt crisis, and the summer tourist season. A number of European countries, notably Greece, are depending greatly on tourist money this year.

If tourists see that there could be long delays in flights, or that they could be stranded in airports by ash cloud alerts, they'll plan to spend their summer vacation closer to home.

The situation is literally up in the air and people don't like that much uncertainty when planning their vacations. The volcanic ash is also generating tremendous uncertainty for many companies around the world, although they don't have a choice but to try to find workarounds. The ash cloud crisis has hit the air cargo industry very hard.

And even if flight diversions to Spain's airports are used at some point to get around an ash cloud over the U.K., the boon to Spain's economy will take business away from the U.K. -- away from Heathrow and other U.K. airports and from hotels, restaurants, taxi, etc. that service those airports.