[Vision2020] Western U.S. Forest Wildfire Activity

Thu Oct 25 22:18:36 PDT 2007

I did a quick look around on the net.  The Santa Ana winds are stronger 
this year than most years in recent history, although 2003 was also an 
exceptionally bad year.  However, the Santa Ana winds have been recorded 
as far back as at least the 1870's.  It's a well-known phenomenon that 
happens in the autumn, winter, and early spring.  It is often at it's 
worst in the fall, because the vegetation has had all spring to grow, 
and all summer to dry out.  The chaparral, in particular, can turn into 
an instantly combustible fuel.  Many people think that the hot winds off 
the desert are what cause the winds to be so fierce and dry, but they 
actually come down from the Rockies and the Sierra Nevadas, when the 
desert is actually cooler.  It takes a high pressure system over the 
great basin and a low pressure system over the Pacific for the winds to 
start.  The air is pushed by gravity and compressed, and then funneled 
through narrow canyons.  This causes the wind to have a low humidity, 
typically as low as 15%.  The dry air helps cause wildfires, and the 
force of the winds can fan them into larger and larger fires.

The winds can also have some beneficial effects, such as cycling much of 
the top level of water in the Pacific off the coast down into the lower 
regions of the ocean, causing colder water from below to circulate to 
the top.  This can bring nutrients to the surface that can help 
invigorate local fish stock.  Granted, people who have lost their homes 
don't give a rat's ass, but the fish care.

Is global warming the cause of these winds?  No, not that I can see.  
They happen every year, and for well-known meteorological reasons.  They 
also happen mostly in the coldest months of the year.  This phenomenon 
is also repeated in other places, most notably the foehn winds in 
Germany.  Is it possible that global warming is increasing the strength 
of these winds?  Yes, I suppose it's possible.  Adding temperature adds 
energy to the system, which can cause the winds to blow stronger.  Did 
global warming cause recent years to be drought years?  Maybe.  It seems 
reasonable that warmer air can dry out drier areas more, due to an 
increased evaporative effect.  However, warmer air can hold more 
moisture, making wetter areas wetter.  More water vapor in the air can 
act as a greenhouse gas, however more cloud cover causes more of the 
Sun's rays to be reflected back into space, and more actual rainfall 
cools the earth.  It still seems to be six of one, half a dozen of the 
other.  Will these winds become stronger and stronger as the earth 
warms?  I have no idea.  Did scientists who believe in human-induced 
global warming predict stronger-than-normal Santa Ana winds?

Paul

lfalen wrote:
> Ted
> I don't disagree with most of the information that you presented from "Science" It is just that there were a few other factors involved.
> Roger
> -----Original message-----
> From: "Ted Moffett" starbliss at gmail.com
> Date: Thu, 25 Oct 2007 14:13:07 -0700
> To: lfalen lfalen at turbonet.com
> Subject: Re: [Vision2020] Western U.S. Forest Wildfire Activity
>
>   
>> All-
>>
>> A report has been issued that at least one of the recent Southern California
>> fires has been "confirmed" to be arson.
>>
>> Of course this has nothing to do with the validity of the Science magazine
>> article on Western USA forest fires and climate change (note the article
>> avoids making claims about the causes of climate change, but does discuss
>> CO2 sequestration related to forests and forest fires, and greenhouse
>> gases).  Nor does it change the fact that the Southern California fires were
>> exacerbated by record drought (worst in 130 years) and intense Santa Anna
>> winds, with hurricane force gusts.
>>
>> Ted Moffett
>>
>> On 10/25/07, Ted Moffett <starbliss at gmail.com> wrote:
>>
>>     
>>> Roger et. al.
>>>
>>>
>>> http://www.terradaily.com/reports/Western_US_States_Swelter_Under_Record_Heatwave_999.html
>>>
>>> http://www.noaanews.noaa.gov/stories2007/s2838.htm
>>>
>>> http://www.sciencemag.org/cgi/content/full/313/5789/940
>>>
>>> The Southern California area was facing the most extreme drought in 130
>>> years.  And had experienced record setting heat waves during 2007.  I
>>> presented the facts.  These factors increased the magnitude of these fires,
>>> do to increased drying of tinder.  Southern California was experiencing well
>>> above normal high temperatures while the fires were burning.
>>>
>>> As to whether the fires in Southern California are arson, none of the
>>> fires yet have been conclusively determined to be arson, as far as I have
>>> determined.  Some already were determined to be accidentally caused by
>>> humans.  Human caused fires happens every fire season, by arson or accident.
>>>
>>>
>>> Another major factor increasing the magnitude of these fires was the
>>> extreme Santa Anna winds...Again, an extreme weather event.  They were
>>> getting hurricane force gusts, upper 70s, 80, 90 mph., creating a blow torch
>>> effect and blowing embers long distances to spread the fire.  To prevent
>>> these conditions from spreading the fire long distances by more clearing of
>>> brush etc. is doubtful.  However, anywhere people have homes with flammable
>>> vegetation nearby, of course this is a risk.  Look at Moscow Mountain.
>>>
>>> The Science magazine article on Western US fire activity presents well
>>> documented data about the earlier arrival of Spring, earlier snow pack melt,
>>> coupled with higher temperatures, increasing the length of fire season and
>>> the magnitude of fires, since 1987, in the Western USA.
>>>
>>> The authors make it quite clear that this increase is not explained by
>>> human land use variables.  Maybe the forests could have been managed better
>>> (more clearing of underbrush) to reduce fire danger, but with earlier start
>>> of Spring, earlier snow pack melt, and higher temperatures, the forests dry
>>> out sooner and more, and this increases the duration of the fire season and
>>> the risk of fires of greater magnitude.
>>>
>>> Ted Moffett
>>>
>>>
>>> On 10/25/07, lfalen <lfalen at turbonet.com> wrote:
>>>       
>>>> Ted
>>>> Whether published in "Science" or not there are a few things missing. I
>>>> think that 1934 was hoitter than it is now. Wheather it was dryer or not I
>>>> don't know. These fire were predominatly the result of arson. The extent of
>>>> the fires we exacerbated by the dense underbrush that resulltd from
>>>> environmetalist not allowing it to be cleared out.
>>>> Roger
>>>>
>>>>         
>>     
>
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