Ash Cloud Chile

[Herman the Navigator]

Is Mount Pleasant closed or is Timmy stuck in Ascension?

I just ask because I tried plotting the ash cloud position given by Buenos Aires VAAC last night, based on the text advisories they're putting out here: Servicio Meteorológico Nacional

The +18 forecast last night had a continuous cloud from SFC to FL400 and from the volcano due east to a longitude far to the east of South Georgia but well north of FI.

The actual report from mid-afternoon today (BST) on the other hand only mentions SFC to FL180 and covers a (relatively) tiny area of Patagonia.

Here are the two messages for comparison (anyone know why there's such a big difference? Is it possible to drastically redefine the cloud limits and still maintain safe flight?):

DTG: 20110606/2130Z
VAAC: BUENOS AIRES
VOLCANO: CORDON CAULLE 1507-15
PSN: S4052 W07220
AREA: CHILE-C
SUMMIT ELEV: 1798M
ADVISORY NR: 2011/011
INFO SOURCE: GOES 12 - GFS MODEL -
ERUPTION DETAILS: CONTINUOUS EMISSION
OBS ASH DATE/TIME: 06/2100Z
OBS ASH CLOUD: VOLCANIC ASH PLUMES 65 NM WID LINE BTN S4052 W07220 -
S3800 W07000 - S3700 W06900 - S3500 W06900 - S3300 W06800 - S3400
W06500 - S3700 W06300 - S4000 W06000 - S4200 W05500
FCST ASH CLD +06HR: 070300Z SFC/FL400 65 NM WID LINE BTN S4052 W07220
- S3800 W06600 - S3300 W06600 - S2800 W06600 - S3300 W06400 - S3500
W06000 - S4000 W05000 - S4800 W02800
FCST ASH CLD +12HR: 070900Z SFC/FL400 65 NM WID LINE BTN S4052 W07220
S3800 W06300 - S3300 W06300 - S2500 W06000 - S3300 W06000 - S3700
W05700 - S4100 W04000 - S5000 W02000
FCST ASH CLD +18HR: 071500Z SFC/FL400 65 NM WID LINE BTN S4052 W07220
S4500 W06800 - S4000 W06200 - S3500 W06300 - S3000 W06400 - S2300
W06000 - S2400 W05600 - S2500 W05800 - S3000 W05900 - S3500 W05500 -
S3800 W05000 - S4000 W04300 -S4200 W03200
REMARKS: LARGE AREA OF ASH CONTINUES TO MOVE TOWARD E. A PLUME IS
VISIBLE IN SATELLITE IMAGERY IR AND VIS CHANNEL. AREA OF REMANENT VA
ASH FROM PREVIOUS EMISION AT S3900 W07000 - S3900 W06600 - S4000
W06400 - S4200 W06500 - S4300 W06800 - S3900 W07000
NEXT ADVISORY: WILL BE ISSUED BY 20110607/0330Z
____________________________________________________________ ______________________________

DTG: 20110607/1330Z
VAAC: BUENOS AIRES
VOLCANO: CORDON CAULLE 1507-15
PSN: S4052 W07220
AREA: CHILE-C
SUMMIT ELEV: 1798M
ADVISORY NR: 2011/014
INFO SOURCE: GOES 12 - GFS MODEL
ERUPTION DETAILS: CONTINUOUS EMISSION
OBS ASH DATE/TIME: 07/1230Z
OBS ASH CLOUD: SFC/FL180 VA CLD 35 NM WIDE LINE BTN S4052 W06630 -
S4127 W07053 - S4200 W06956 - S4318 W06907 - S4432 W06905
FCST ASH CLD +06HR: 071930Z SFC/FL180 S4052 W07220 - S4130 W0550 -
S4200 W06140 - S4400 W06130 - S4230 W06640 - S4052 W07220
FCST ASH CLD +12HR: 080130Z SFC/FL180 S4052 W07220 - S4100 W06700 -
S4130 W063500 - S4230 W05800 - S4600 W05800 - S4310 W06454 - S4133
W06930 - S4052 W07220
FCST ASH CLD +18HR: 080730Z SFC/FL180 S4052 W07220 - S4000 W06700 -
S4000 W06300 - S4300 W05400 - S4500 W05800 - S4200 W06400 - S4052 W07
220
REMARKS: VA PLUME IS VISIBLE IN MULTISPECTRAL SATELLITE IMAGERY
AREA OF REMANENT VA ASH FROM PREVIOUS

[aterpster]

materazzi:

Thank you for the great photo!

[aterpster]

The thought that this is connected to the earthquakes is fascinating.

The Rim of Fire makes us little piss ants insignificantl

[aviate1138]

Nube de ceniza - La erupción del Puyehue - Cordón Caulle en Riñinahue - ELPAÍS.com

removed ajc-bue's IMGs

[sdbutters]

Any Idea

Hi there, any idea for how long?

Cheers

[ajc-bue]

All fights cancelled in EZE today. Flights to Patagonia cancelled until next 15.
Ash cloud at 6.000 meters traveling south-west to north-east.

[ajc-bue]

Thanks Aviate!

[WetFeet]

From the New Zealand Herald today:

International and national flight routes could be disrupted for the next week as ash plumes from the CordnCaulle volcano in southern Chile enters New Zealand airspace.

[ozbiggles]

Qantas CXing some flights (well Jetconnect anyway)between Aus and NZ.
Flights between Mainland and Tassie look like they might be in trouble too.

[mm43]

Qantas and Jetstar/Jetconnect are cancelling trans-Tasman services between Sydney/Melbourne and Christchurch/Queenstown, and NZ domestic services between Auckland and Christchurch/Queenstown.

Ash cloud expected to spread northward over NZ during the day and be near AKL by 0600z 12 June.

VOLCANIC ASH WARNINGS [SIGMETs] DARWIN RSMC 18:39 UTC, 11/06/2011 -------------------------------------------------------------------- ***** Received at 18:22, 11/06/11 *****
NZZC SIGMET 14 VALID 111821/120021 NZKL- NZZC NEW ZEALAND FIR VA ERUPTION MT CORDON CAULLE PSN S4031 W07212 VA CLD OBS AT 1800Z FL200/350 S4100 E17015 - S4215 E17530 - S4815 E16815 - S4600 E16515 MOV ENE 30KT FCST 0000Z VA CLD APRX S3900 E17130 - S4015 E17815 - S4815 E16815 - S4600 E16515= *****

Received at 18:17, 11/06/11 *****
NZZO SIGMET 36 VALID 111817/120017 NZKL- NZZO AUCKLAND OCEANIC FIR VA MT CORDON CAULLE PSN S4031 W07212 VA CLD OBS AT 1800Z FL200/350 S4000 E16700 - S4600 W17300 - S5500 W16000 - S5300 E16300 MOV ENE 30KT FCST 0000Z VA CLD APRX S3800 E16700 - S4400 W16945 - S5400 W15800 - S5300 E16300=

[peter we]

Chile volcano: Qantas cancels Melbourne flights
Qantas aircraft at Sydney's international airport - 12 June 2011 Qantas said it was trying to contact all passengers affected by ash cloud cancellations


Qantas has cancelled all its flights in and out of Melbourne, Australia, because of ash drifting over the Pacific Ocean from a volcano in Chile.

Qantas had already cancelled flights to and from Tasmania and parts of New Zealand. Other airlines have also grounded flights in the region, stranding thousands of travellers.

Australian airline Qantas said it was too dangerous to fly through the ash.

Surely this can't be right, flights are cancelled only due to government incompetence, not because of Volcanic ash, which is imaginary.. right?

BBC News - Chile volcano: Qantas cancels Melbourne flights

[mm43]

VOLCANIC ASH WARNINGS [SIGMETs]
DARWIN RSMC 19:38 UTC, 12/06/2011
--------------------------------------
***** Received at 18:14, 12/06/11 *****
NZZC SIGMET 35 VALID 121814/130014 NZKL- NZZC NEW ZEALAND FIR VA ERUPTION MT CORDON CAULLE PSN S4031 W07212 VA CLD OBS AT 1800Z FL200/380 S3545 E17045 - S3815 W17945 - S4815 E16815 - S4545 E16515 MOV ENE 25KT FCST 0000Z VA CLD APRX S3515 E17115 - S3645 W17845 - S3830 W17945 - S4815 E16815 - S4545 E16515=

Imaginary? I think not; the rising sun revealed at pale orange high level haze.

[Captain Dart]

Emirates, CX and SQ, operated into MEL early this morning (Monday) and nothing noted, except that MEL ATC excelled themselves with the reduced traffic.

No 'haze' in the sky at dawn on the trip home either; just the one in my brain.

[reynoldsno1]

Most flights in NZ operating at lower levels - this ash cloud has come from the WEST - not across the Pacific. Presumably the volcano is still puffing away, so we're going to be in some sort of conveyor belt scenario...

[Herman the Navigator]

Originally Posted by peter we

Surely this can't be right, flights are cancelled only due to government incompetence, not because of Volcanic ash, which is imaginary.. right?

BBC News - Chile volcano: Qantas cancels Melbourne flights

No one has ever said that volcanic ash is imaginary; just that London VAAC/UKMO forecasts have included vast areas where the ash densities are so low and the particles so fine that neither engine damage nor abrasion is realistically going to happen.

Here's an extract from a paper co-written by UKMO in 2007, which clearly shows that there are differences in approach, which make UKMO's figures significantly more pessimistic than other VAAC:

There is currently no consistency in the way that the participant VAACs define the ash-cloud boundary (Table II) with thresholds depending variously on the source release rate used, availability of satellite data for comparison and forecaster judgement. The London VAAC, for example uses a visual ash-cloud look-up table to determine hazardous ash concentration as a function of the plume height. This table was originally constructed by NOAA for the VAFTAD dispersion model and was based on correspondence between an ash cloud modelled with a 1 g source and that seen on satellite imagery for real eruption scenarios. As such, it is an empirical relation and may not be appropriate for all types of eruptions. The Washington VAAC has a variable concentration threshold for determining the ash boundary from the output of the model. The default threshold is the value in the NOAA table. The forecaster then previews output using thresholds 10, 100, and 1000 times the default and chooses the appropriate threshold based on forecaster judgement, in conjunction with satellite imagery.

[WetFeet]

chooses the appropriate threshold based on forecaster judgement

And we know how good they are at forecasting! Wouldn't trust that either.

[Herman the Navigator]

Originally Posted by WetFeet

And we know how good they are at forecasting! Wouldn't trust that either.

So, London VAAC don't use forecaster judgement and Washington VAAC do (and have done for several years). Where is your evidence of damaged aircraft and engines in the Washington VAAC AOR, to back up your claim that forecaster judgement isn't reliable?

[foxfire42]

Here's an extract from a paper co-written by UKMO in 2007, which clearly shows that there are differences in approach...

I think I'm right in saying that the Met Office has changed things since 2007 at least once, if not twice, as new data becomes available to them.

[Herman the Navigator]

Originally Posted by foxfire42

I think I'm right in saying that the Met Office has changed things since 2007 at least once, if not twice, as new data becomes available to them.

The difference in approach between London VAAC and (say) Washington VAAC is still there. London is still using the same NAME model and setting hard limits, rather than allowing any interpretation of the model ouput.

The changes that have occurred due to "new data" have been:

1. a 10x raising (to 2 mg/m3) of the original NOAA table threshold of 0.2 mg/m3 for the April 2010 eruption, as an immediate result of the airspace closures. No additional engine test or forecasting data was involved.

2. an additional 2x raising of the threshold to 4 mg/m3, for those who signed up to it in May 2010. Again, no additional engine test or forecasting data was involved.

The original 0.2 mg limit for the April 2010 eruption was the direct output of the quoted NOAA table, with no interpretation (as explained by the 2007 paper). According to the paper, Washington VAAC could have potentially gone to a figure 1000x greater i.e. 200 mg/m3, in the same scenario, without anyone raising concerns about flight safety.

[kbrockman]

Another volcano, now in Africa

News: Eritrean volcano affects East Africa and Arabia

Volcano Nabro (also reported as Dubbi) in Eritrea has erupted today throwing ash clouds up to FL450. The ash clouds currently affect East Africa and the Arabic Peninsula.

Ash Advisory released by Toulouse VAAC on Jun 13th 18:00Z: