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From the NATS website:

Quote:

Statement on Icelandic volcanic eruption: Friday April 16, 2045

The volcanic ash cloud continues to affect UK airspace. Following the latest update from the Met Office, NATS advises that the restrictions currently in place across UK controlled airspace will remain in place until at least 1300 (UK time) on Saturday April 17.
There are currently no airspace restrictions in Scotland, Northern Ireland and in an area over the North Sea that includes the Shetlands and Orkney Isles. Manchester, Liverpool and all airports North of those may be available from 0400 (UK time) – 1000 (UK time) for departures to and arrivals from the North and West subject to individual co-ordination. However, please be advised that the situation is continuously changing. Forecasts indicate that the ash cloud is expected to return over Northern England at 1000 (UK time) and it is likely that restrictions will be reintroduced.
Please note these arrangements do not mean that all flights will operate. Anyone hoping to travel today or tomorrow should contact their airline before going to the airport.
We are looking for opportunities when the ash cloud moves sufficiently for us to enable some flights to operate under individual coordination with ATC.
We will review further Met Office information and at 0900 (UK time) on Saturday we will advise further arrangements.
We continue to work closely with airports, airlines, and the rest of Europe to understand and mitigate the implications of the volcanic eruption.

Restrictions extended till 1300 Sat. Our company are telling us that NATS are using a computer model based on a Canadian eruption from the past. This eruption had different ash densities to the current Icelandic one. Upshot is they are pressurising NATS to rethink the model. Personally I don't rate their chances.

BBC News just announced no flights until 1300 Saturday. 2100 Friday.

Another BIG explosion just took place:eek:

Eyjafjallajökull frá Hvolsvelli

If you have trouble viewing the webcam(s) this happened minutes ago:

http://i904.photobucket.com/albums/a...9/current8.jpg

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Is the Ash Cloud radar reflective? And if so, at what radar frequencies? (cm, mm, etc)

At concentrations already known to affect jet turbine blades, radar detection is probably not feasible. The primary way that volcanic ash clouds are detected involves multiband infrared sensors. One example is discussed here.

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P.S. Anyone know what the Carbon Footprint of the Volcano is? How will Iceland offset its emissions?

Using a conventional definition of "carbon footprint" (such as this one), the volcano's is nil, because its emissions are not the result of human activity. Furthermore, as long as significant ash releases continue to occur, the climatic impact of this erruption is self-offsetting because atmospheric ash has a stronger cooling effect than CO2 has a warming effect.

@thetimesreader84,

Ash cloud has very little moisture and typically not practicable to track effectively with radar. In blunt terms: it tend to be invisible.

I thought the earlier post with the satellite image of the actual plume was telling. Surely with modern technology of satellite imagery, the airspace closure could be narrowed down significantly to just the areas closest to the plume for avoidance? One wonders if we might be slightly over-reacting just a tad.
As I recall in Eric Moody's encounter (based on the chapter "Strange Encounter" in the book "Emergency") the BA009 flew very close to the volcanic ash cloud and not 700 miles away from the eruption as is most of UK airspace.
With the significantly dispersed cloud tracking over the UK there must be a much lower risk of contamination.
One problem is nobody seems to have any data as to acceptable or permitted levels of ash concentration affecting jet engines.

The other big problem, it now seems to me; is that someone is going to have to make a very difficult decision as to when to re-commence operations against an extremely hard to gauge risk of engine failure caused by volcanic ash penetration. I don't envy those who are going to have to take that one !

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Is the Ash Cloud radar reflective? And if so, at what radar frequencies? (cm, mm, etc)

Yes, it is. Depending upon the density of ash it can be visible on the cm scale, but for concentrations similar to those over northern europe you need a mm radar.
This is quite an interesting read on the subject:
http://www.ece.mtu.edu/faculty/wfp/articles/diel8.pdf

The best way to detect the ash is with lidar rather than radar, though. Only one is operational now, but there's currently a proposal to reactivate a few space based lidars for north sea/iceland overpasses. Not an easy job though and by the time the beauracracy has percolated it'll probably be too late.

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Or for a/c to avoid ash concentrations themselves (like routeing around CBs for example).

Aircraft are incapable of detecting the ash (unless they're lucky enough to eyeball it). The wx radar on almost all aircraft uses too long a wavelength, so you'd need an very dense cloud.
I'm also not sure how an aircraft radar would deal with volcanic ash. It behaves differently to rain, etc, so there's a chance that much of the information could be filtered out in software before it even reached the cockpit. I don't know enough to comment further on that though.

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P.S. Anyone know what the Carbon Footprint of the Volcano is? How will Iceland offset its emissions?

It's actually carbon negative right now due to the lack of aviation. ;)
Not sulpher negative though, and I have no idea how this affects the weather...ash is a rather good absorber of sunlight.

(edit)

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Surely with modern technology of satellite imagery, the airspace closure could be narrowed down significantly to just the areas closest to the plume for avoidance?

Which is what has happened. The plume is currently sitting over most of northern Europe. Worst concentrations (thick enough for me to see without the need for fancy computer software) are over the West coast of Norway, central England, southern Sweden and Holland. There's a few bits of something that looks like thick ash over Germany too, but I can't tell if it's ash or a very strange cloud.
As of an hour ago Iceland is more or less clear by the looks of things.

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BA009 flew very close to the volcanic ash cloud and not 700 miles away from the eruption as is most of UK airspace.

And how far away from Iceland is Finnish Airspace....look at the engines from the Finnish Air Force F-18 posted earlier?

Why do so many people do not just simply grasp the fact it's there even if yoou can't see it?

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But surely the particulates are bigger than water droplets (or at least no smaller), and surely more radar reflective?

They are much much smaller - which is the entire problem. That's why we can't see them and that's why they are a problem for aviation. Small things clog up small holes. Aircraft aren't really designed to deal with ash, even sand and dust particles are much bigger than what is spewing out of that volcano.

For those interested, to draw your own conclusions on wether the no fly zone by Eurocontrol is waranted or not. To give some perspective Mt Eyjafjallajökull is 1666m/5465,8 ft.

This camera is located aprox 35km west of the mountain

http://http://eldgos.mila.is/eyjafja...thorolfsfelli/

Incredible sight on the webcams at the moment. This is far worse than Tuesday's event. If you can't view the webcams, I'm happy to take screen grabs and post here. Maybe mods are ok with this? I'm sure some won't be able to view the 'cams..

22 Degree Halo, how is it possible that on your picture at 21 GMT is so bright as it is midday? I don't get that... please explain it to us, thanks in advance! :}

It looks St.Petersburg and Moscow airports still operating at full capacity even they are shown in the affected area?
And why we don't hear about dozens of crashes there?

GfaRm

Are you saying this clock is wrong?
http://i904.photobucket.com/albums/a.../current13.jpg

Top right.

Btw, it's getting dark now ;)

Vodafone.is - Eruption in Iceland 2010

Look at the time - 30 mins later

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Originally Posted by CargoOne

And why we don't hear about dozens of crashes there?

Nobody should expect crashes - "only" damage to the engines, which is enough not to fly!

sunrise/sunset in Iceland (Reykjavik).

For info: sunrise/sunset

16 Apr 2010 05:53 21:04

20 Jun 2010 02:55 00:04:ok:

22 Dec 2010 11:23 15:30:\

Position for Reykjavik is 64°08′N 21°56′W

Local time: UTC