Ice Capping? Column Collapse?

[William Riggles]

On second thought, the "weather rock" is something almost as good as a multimillion dollar study of columns. Keen observations of indicators using your 5 senses with the 6th being your experience give you a feel for all the dynamics of a blowout.

Something we haven't mentioned are clues after the fire. Fire scars and needles that point the direction the fire moved through.

Like a detective looking for clues, being a good observer covers more phenomenon than all the instruments NASA could ever come up with.

My thing is, I want to know where embers leave the column! I think of a hail storms and how just before or after the main rain the hail hits. Hail as we know gets caught in updrafts near the top of a thunder head and accumulates layers of water or slush and freezes. Try switching the vacuum cleaner hose to the exhaust side of a shop-vac and balance a ball on the air flow.

This was my main reason for wanting to study reflective material with radar. We can't see this part of the process! I feel it's important to understand where embers fall out and land in order to predict where spotting will occur.

Presently I think debris get flung from the column if it's vertical and dropped from the column if it's horizontal. The majority is ejected at the top when it pushes through clear air and mushrooms or hits a layer of cold air and ice caps as seen in the videos. I was just looking for data to back this up!

[mikef]

In the case of the 18 Jan 2003 Canberra pyroCb black hail was found
30 km east of the storm. That's a pretty far toss!

Post-fire examination of the debris and burn field would be invaluable.

One thing to keep in mind for the future is that the GOES satellites can be commanded into Rapid Scan Mode, which means pictures every five minutes
or so. I'm not an expert on how to get this to happen, but it should be
explored IMO.

[mikef]

Hi all,

Two items:

1. I've been having an offline convo with Fuels Guy and it came to mind for me to weigh in on the term "ice capping." It was apparent to me that many interpreted the white clouds popping out above the smoke in the time lapses (and of course the many beautiful pyrocumulus pics seen in general) as "ice caps." While surely ice clouds do form from convection and pyroconvection, a general rule is that if the cloud has the texture we call "caulifloury" that cloud is composed of liquid water droplets. I'm sure I could be challenged on that, but I believe that is a pretty well worn assumption among meteorologists. It may seem unintuitive, but liquid droplets can remain in that state at temperatures way below freezing (down to ~-40F). Ice particles don't start forming in any great abundance until the supercooled air gets very high and cold. The visual cue for ice-laden clouds is a filmier, smoother texture. The pileus clouds we've talked about are ice. Tstorm anvils are ice. But those bubbly, caulifloury textures bespeak liquid. Now none of this is stated to imply anything w.r.t. column collapse. Just a clarification of what the clouds we see are composed of.

2. I have results for the 30-Mile fire on the day others have commented on as fateful--10 July 2001. The results may be illuminating for those who know well what went on up close to the extreme fire behavior that day. Here are GOES loops (with the now familiar file naming for visible, shortwave (ch2) and thermal (ch4) IR.
http://rammb.cira.colostate.edu/proj...01/visloop.asp
http://rammb.cira.colostate.edu/proj...01/ch2loop.asp
http://rammb.cira.colostate.edu/proj...01/ch4loop.asp
Here's what I see that may be noteworthy:
Loops start at 12 UTC (05 PDT).
30-Mile hot spot (see ch2, shortwave IR) starts at 2215 UTC (1515 PDT)
Dramatic jump in hot spot size between and 0000 and 0030 UTC (1700 - 1730 PDT).
Deep pyroconvective pulse also at 00-0030 UTC.
Pyroconvection continues until ~04 UTC (21 PDT).
At 03 UTC (20 PDT) a particularly hot pixel (ch4, thermal IR channel) shows up.
* This may indicate another sharp increase in flaming intensity.
Other fires of note:
* WA, south of 30-mile. Never gets real big or hot.
* WA, SE of 30-mile.
* BC, near BC/AB border. This fire gets real hot/big, but no obvious deep pyroconvection.

Comments? Criticisms? Rotten tomatoes?

[DitchDigger]

Don't know if anyone has seen this, but this poster explains plumes and collapses very well (IMHO - not that I know anything) http://www.gehotshots.org/fire_library/fire_plume.html It's available as a free high res download

[William Riggles]

Great Poster! Full Size Download

Why are we getting plumes up in the stratosphere?

Maybe a combination of the right topography, fuel conditions, weather (winds and atmospheric conditions); all coming together at the same time.

It's difficult for a large diameter fire to get O2 to all of the fire. Many interior parts are starved from O2.

But, certain terrain allows for unrestricted air flow! As a fire is driven up the classic chimney canyon it's spotting on the backside of the hill. The rising air from the main fire, draws air up the backside fueling the spots life to so that the whole peak is torched from all sides.

In the above design the air movement flows as opposed to rushing in and making a 90 degree direction change. On top of that, it flows from all directions.

Add to that bug kill-dry heavy fuels, and an atmosphere conducive to venting, and I think you have the classic blow-out.

On a very large scale, fire goes up one side of a range and spots into many drainages simultaneously.

[OB1309]

G'day all!

Late coming in to this.

Slihtly off topic but relevant.

The Bushfire Cooperative Research Centre has published a report which may have some relevance.

Initial overview can be found at www.bushfirecrc.com/news/slots2.html. I assume the US fire weather forecasters are aware of this. For mine it seems to explain the column collapse that I've seen referenced in earlier posts.

Regards

OB
OZ

[stringtown]

Thanks OB- I went ahead and found the articles from Australian Meteorolgy Magazine about this study, it was published in 2 parts, I didn't get a chance to read them- but here they are if others want to read them.

http://www.bom.gov.au/amm/200804/mills1.pdf

http://www.bom.gov.au/amm/200804/mills2.pdf

[FC180]

Originally Posted by NMAirBear

All,

I just got off the phone with Tim Lynch regarding his paper. He is completely right on with his dissertation regarding Recognition Primed Decision-making (RPD) and I made him well aware of that. RIGHT ON, TIM!!!

This thinking is akin to what Doug Campbell has for years been referring to as recognizing the "fire signature".

There needs to be a higher level movement in wildland fire management to stress the importance of experience as opposed to the importance of training. This is not the Boy Scouts where you earn merit badges....this is real life with actual lives at stake if folks do not use RPD. I have long had that attitude with regard to how, for instance, S490/S590 Fire Behavior courses are presented.

Tim Stubbs
Fire Behavior Analyst/Air Tactical Group Supervisor

The problem with experience is it takes so long to acquire. Thats what training is all about, to accelerate the recognition that occurs on subsequent experiences so that they happen during experience. That is what the Fire Behavior series is all about, and all presenters of the material need to remember that: you are there to remind students of what they have seen and what others have seen, and relate it to the hard science behind it so that they can recognize the antecedent elements and predict the future based on the hard science involved.

[Mellie]

mikef,

I see you're online now. Well maybe you've already gone...

I've had a question about whether the Big Bar Complex (Megram Fire) blowup on Oct 2 of 1999 had upper atmosphere effects like the ones you've shown and talked about. The fire made a 5 mile run in one day after being held on Devils Backbone (Trinity Wilderness, norcal Shasta-T and Six Rivers National Forests) for about a week by the shots.

OK, I just did a search of theysaid and here's my description of that event from Jan 24, 2000. I even sent in the two maps then that show the effect of the blowup:

http://www.wildlandfire.com/pics/other/bb1.jpg
http://www.wildlandfire.com/pics/oth...owup-10-02.jpg

To refresh the memories of the early firefighters on the Big Bar, here's the
map of the Onion, Fawn and Megram fires from about the time DuBois is speaking
of. This is from the Northcoast Journal, Arcata CA, October 7, 1999. There's
another map I got someone to pull off the web after the blowup of the blowdown
-- which created those huge lobes on the Megram to the west.

This complex, especially the eastern side (well, the middle, really between Onion and Megram), got me involved in wildland fire, and I find I'm now approaching my 10 year anniversary.

Whooo hoooo!

(... and I hear FireGeek is coming to my area, will have to get together with you dude! Handheld GIS used on the fireline was a fairly new phenomenon at the time of that fire...)

mikef and all,

I know the discussion did not stop... Is there any way you could share some of the followup and ongoing dialog about these kinds of events? I was really enjoying reading all the theorizing and questions.

[mikef]

Hi Mellie,

I'm glad you reinvigorated this thread.

Re. Big Bar, thanks for bringing it to my attention. A little googling showed that this one ranked up there with the biggest fires between 1997-2008.
http://www.nifc.gov/fire_info/lg_fires.htm
A quick look shows that there was probably a high-altitude plume from this
episode but I can't say much more at this time. However, it appears from
the satellite evidence the biggest blowup might have been 3 October instead
of 2 October. Knowing that date will help refine our search. Should I look
into 3 October too? It may be more than a week before I can report back...my GOES co-conspirator is gonna be lazing in Hawaii next week (harumph

BTW, we had lots of discussion at the American Meteorological Society conference on fire and forests last week in Kalispell. Much interest in
an up-close-to-fire measurement campaign. Proposals and other initiatives
are underway.

mikef