Forecast from Glidemet

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Also, take a look at this night-time time lapse from last night. There’s a lot of lightning in that plume! That picture is from the same gallery of volcano pictures I linked to previously. Many great shots in there.

Keep an eye on the volcano webcam too, although cloud cover might obscure the image at times. At time of writing though, the volcano is really going for it again. Also, I’m told that last night the lightning was easily visible on the webcam.

Finally, the Isles of Scilly helicopter shuttle has finally been suspended.

Forecast from Glidemet

Still smokin’

Well, there’s no real short answer.

But here’s a summary how “how it works”. Everything is taken from the ICAO Manual on Ash, which, if you want the bible on ash and aeroplanes, is what you should be reading. ICAO is the International Civil Aviation Organization, the UN body which sets standards for international air travel.

The world is covered by nine Volcanic Ash Advisory Centres, which retain the capabilities to detect ash via satellite and forecast its spread using “dispersion” computer models. They provide guidance to “meteorological watch offices”, which in turn produce “SIGMETs”, coded bulletins which are transmitted to pilots to warn them of dangerous weather or, as in this case, ash. Sigmets are normally valid for six hours at a time, but volcanic ash sigmets also contain an 18 hour “outlook” for the use of long-distance flights and flight planning. As a result, the Volcanic Ash Advisory messages extend to 18 hours ahead, to inform the outlook part of the sigmets.

• Met Office Volcanic Ash Advisory messages

Therefore, new advisory messages are produced every six hours during a major volcanic eruption. That’s why you are hearing in the media, every six hours, that the airspace closures are lasting another six hours. At the bottom of the messages you can view using the link above, you can read remarks about volcano (to convert FLs, flight levels, into feet, times by one hundred), and when the next update is due.

NATS, the National Air Traffic Service, controls UK airspace. It updates shortly after the Met Office, using the forecast data.

• NATS statements

So, when will the ash disperse? When either the upper-level winds change and blow the ash away, or the volcano stops erupting (but even then it will take some time for the last ash to reach us, and then for what’s already up there to disperse). From purely eye-balling ECMWF upper-air forecasts, if anything the upper wind looks like it’s only go to blow straight from Iceland to the UK for at least the first half of the week, but towards next weekend will move away.

As far as the eruption itself is concerned, well, you can see on the volcano webcam, now skies in the area have cleared, that there’s still plenty coming out of the volcano. How long that lasts for is impossible to forecast. The Icelandic Met Service is providing plenty of information — click on the “eruption” link at the top of their home page.

What’s happening over the UK? The Met Office Icelandic volcano eruption page is being regularly updated, and the forecaster’s blog is very interesting reading, reporting that ash has been observed over the UK at 6,000 ft and lower.

The Natural Environment Research Council has also been probing the cloud with its research aircraft. Unfortunately that aircraft can only fly to 15,000 ft — the much larger and more capable FAAM aircraft cannot be used as it has been stripped of instruments ahead of a repaint.

There has also been confirmed deposits of ash. Sheffield University has confirmed that ash fell in Sheffield.

Why can’t I see anything? (Again, from the ICAO Manual on Ash) Volcanic ash is made mainly of tiny particles of silica, too small to be seen by the naked eye when suspended in the air. By the same token, they are too small to be detected by weather radar, whether ground based or on aircraft. Often the only way pilots know they have flown into an ash cloud is from the acrid smell, the abrasion of the windshield (making it look like it’s frosted), and in the worse case, by the loss of thrust as the ash clogs the engines!

What damage can this ash do? Ash is much harder and more abrasive than sand and “normal” dust. It can severely damage jet engines resulting on repairs that can cost millions. Indeed, some Finnish jet fighters have been damaged, and Easyjet is worried about engine damage is flight is allowed again too early.

How much is there really up there? This is partly answered above by the fact that ash has been detected in the air and on the ground in the UK, and the Finns have provided stark evidence that it is dangerous. However the ICAO manual does explain that forecasting actual concentrations is not possible—only where ash from a volcano will have spread too. Flight within the area where ash is present is dangerous, or to quote the manual, “AVOID AVOID AVOID”. As data from the research flights and from the Icelandic Met Service is sent to the Met Office, they will be able to refine the forecasts as much as possible.

And finally, who produces the most CO₂? The planes, by a long way…

Forecast from Glidemet

How long is the Icelandic volcanic ash going to last (and other questions)?

The Volcanic Ash Advisories are continuing to be updated.

Given that the upper winds are leading straight from Iceland to us, and will do for some time, it’s currently not possible to say when the ash may no longer pose a hazard (that’s my own personal intrepretation, nothing official).

The restrictions on air travel due to the ash are likely to be continually extended every six hours or so, as new ash dispersion forecasts are produced by the Met Office (in accordance with fixed agreements for producing such forecasts) until there is no longer a risk.

The Met Office has this evening released a quite comprehensive press release about the Icelandic eruption. Do have a read through.

I’m reliably informed by those with better colour-vision than myself that ash is visible on the EUMETSAT ash imagery.

The Met Office has also made available their own volcanic ash imagery. You’ll have to manually select the latest image from the times available.

However, you really can’t miss the ash plume in this special visible-light image:

Courtesy NASA/MODIS Rapidfire. For other resolutions (down to 500 m/pixel) click here. You can also access Rapidfire imagery through the link in the sidebar on the left.

Here’s some pictures from the air of the initial eruption on Wednesday morning.

Virtual Radar shows were the airliners are — or are not. Nothing in the skies of northwest Europe.

A person called Matthew Taylor operates one of those “virtual radar” aircraft tracking systems (got to get me on of those), and has produced some screen shots of the affect of the VAAs, SIGMETs and NOTAMs on UK air traffic. Here’s what the skies looked like at 1120z. Note that flights were being routed south of the predicted location of the ash cloud, generally up the Channel rather than further north. But just one hour later, UK airspace has emptied.

My own observation was that almost everything stayed on the ground today. Those operating piston-powered aircraft in the south of the UK would probably have been just fine operating below the level of the temperature inversion (which is hard for things to cross, either way), although personally I would have not wanted to risk any extra engine wear. As it was though, I spent the afternoon at Cliveden House, a bit north of Heathrow and White Waltham, where the sky is usually full of airliners and SEPs buzzing around lower down, and the only thing I saw airborne was an EC135 — possibly an air ambulance or the police. I did also hear a piston aircraft near Reading later in the day, very much to my surprise.

Further I have heard that the Penzance—Isles of Scilly helicopter kept flying, and certainly nothing on their website suggests that they packed it in, but they are on the edge of the affected area.

Forecast from Glidemet

Icelandic volcanic ash update

I honestly don’t know what the effect of ash on piston-powered aircraft is (looking into it though), but these are the Volcanic Ash Advisories being issued by the Met Office (the nominated Volcanic Ash Advisory Centre for the North East Atlantic area). They update every six hours or so. They’re also available in text form with co-ordinates for the edges of the affected areas.

Users will also want to consult NOTAMs for this event. They will refer to the ash advisory messages — these are what I have linked to above. However at time of posting the latest NOTAM follows:

Q) EGXX/QAFXX/IV/NBO/E/000/999/5441N00219W999
B) FROM: 10/04/15 12:00C) TO: 10/04/15 17:59

E) A VOLCANIC ASH CLOUD, ORIGINATING IN ICELAND, IS HAVING A
MAJOR IMPACT AFFECTING UK AIRSPACE. UK AREA AFFECTED:
610000N 0100000W 610000N 0000000W 600000N 0000000W
570000N 0050000E 550000N 0050000E 503039N 0013824E
493000N 0041900W 493957N 0080000W 510000N 0080000W
522000N 0053000W 535324N 0053000W 553600N 0020800W
574700N 0015500W 604402N 0100000W 610000N 0100000W
SFC/UNL
OPR SHOULD REFER TO VA ADVISORY 20100415/0600 FOR FURTHER INFO.
IN ACCORDANCE WITH ICAO VOLCANIC ASH CONTINGENCY PLAN,
NO IFR CLEARANCE WILL BE ISSUED FOR PENETRATION OF THE FORECAST
CONTAMINATED AREA THAT LIES WITHIN UK AIRSPACE.

Do not use the above information for flight planning etc. — check the latest NOTAMs yourself.

Here’s a bit of video of the eruption filmed from the air yesterday morning.

Here is the Meteosat Ash Detection imagery for Iceland, where you can may see something of the progress of the ash in real-time, but you’ll need read the ash imagery interpretation guide (Powerpoint file) to understand what you’re looking at, and colour-vision better than mine. The ash is not that dense over the UK, and there’s a lot of high-level cirrus in the area which is contaminating the images somewhat.

You won’t see the ash (away from the volcano itself) on normal satellite images such as high-res visible, or infra-red. It’s too thin when viewed top-down as much as anything. The above linked images look for the exact signature of volcanic ash and sulphur dioxide (which is, reportedly, being smelt in the Shetlands!).

However, for your viewing pleasure, this is what the eruption looked like at lunch time on Wednesday (courtesy the Icelandic Met Office, NOAA, and EUMETSAT):

For what it’s worth the upper-level winds will be bringing air from Iceland for several days yet, so how long this situation continues is entirely dependent on how long the eruption in Iceland lasts.

Finally, here is the very detailed ICAO Aviation Manual on Ash (and other stuff) (pdf).

Forecast from Glidemet

Icelandic volcanic ash advisory information