[Vision2020] Western U.S. Forest Wildfire Activity

[Ted Moffett]

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
> -----Original message-----
> From: "Ted Moffett" starbliss at gmail.com
> Date: Wed, 24 Oct 2007 13:45:27 -0700
> To: "Bruce and Jean Livingston" jeanlivingston at turbonet.com
> Subject: Re: [Vision2020] Western U.S. Forest Wildfire Activity
>
> > All-
> >
> > Regarding the ongoing Southern California fires, and the very important
> > issue of Western US fire potential (especially in Idaho) and causes in
> > general, the following fact and science based sources are critical.
> >
> > Read about the record drought and heat waves for Southern California
> (both
> > this year), coupled with the findings from the research on Western USA
> > fires, in the Science magazine article below, co-authored by the
> scientist,
> > Thomas Swetnam (University of Arizona), who I referenced at the start of
> > this thread, who was interviewed on CBS 60 Minutes last weekend on the
> > subject of wild land fire, with astonishing timing, given the explosion
> in
> > the Southern California fires that occurred immediately after:
> >
> >
> http://www.terradaily.com/reports/Western_US_States_Swelter_Under_Record_Heatwave_999.html
> >
> > *Parched California has driest 'rainy season' on record*
> >
> > Los Angeles (AFP) July 1 - Los Angeles suffered through the driest rainy
> > season on record in 2007, marking the least amount of precipitation here
> in
> > the 130 years
> >
> > http://www.noaanews.noaa.gov/stories2007/s2838.htm
> >
> > In Los Angeles, the lack of rainfall led to the driest water-year to
> date
> > for the city since records began in 1877. From July 1, 2006, through the
> end
> > of March, downtown Los Angeles had received only 2.47 inches of rain,
> almost
> > one foot below the normal amount of rainfall for the period.
> >
> > In the West, where mountain snowpack is relied upon to supply water
> needs
> > throughout the region, below-average rain and snowfall have become
> > increasingly common. In only two of the past nine years has snowpack on
> > April 1 been at or above the long-term average in at least half the
> region.
> > --------------
> >
> > For those who wish to skip most of the Science magazine article, here is
> a
> > critical finding of their research, indicating human land use is not the
> > cause of the documented increase (note not the cause of the "increase,"
> not
> > that humans do not start fires) in Western USA fires in recent decades:
> >
> > http://www.sciencemag.org/cgi/content/full/313/5789/940
> >
> > We compiled a comprehensive database of large wildfires in western
> United
> > States forests since 1970 and compared it with hydroclimatic and
> > land-surface data. Here, we show that large wildfire activity increased
> > suddenly and markedly in the mid-1980s, with higher large-wildfire
> > frequency, longer wildfire durations, and longer wildfire seasons. The
> greatest
> > increases occurred in mid-elevation, Northern Rockies forests, where
> > land-use histories have relatively little effect on fire risks and are
> > strongly associated with increased spring and summer temperatures and an
> > earlier spring snowmelt.
> > --------------------
> >
> > I will excerpt a few more paragraphs from this article:
> >
> >
> > *Science* 18 August 2006:
> > Vol. 313. no. 5789, pp. 940 - 943
> > DOI: 10.1126/science.1128834
> >  Prev <http://www.sciencemag.org/cgi/content/short/313/5789/936> | Table
> of
> > Contents <http://www.sciencemag.org/content/vol313/issue5789/index.dtl>
> |
> > Next <http://www.sciencemag.org/cgi/content/short/313/5789/944>
> > Research Articles Warming and Earlier Spring Increase Western U.S.
> Forest
> > Wildfire Activity *A. L.
> > Westerling,1,2*<
> http://www.sciencemag.org/cgi/content/full/313/5789/940#COR1>
> > H.
> > G. Hidalgo,1 D. R. Cayan,1,3 T. W. Swetnam4 *
> >
> > http://www.sciencemag.org/cgi/content/full/313/5789/940
> >
> > We compiled a comprehensive database of large wildfires in western
> United
> > States forests since 1970 and compared it with hydroclimatic and
> > land-surface data. Here, we show that large wildfire activity increased
> > suddenly and markedly in the mid-1980s, with higher large-wildfire
> > frequency, longer wildfire durations, and longer wildfire seasons. The
> greatest
> > increases occurred in mid-elevation, Northern Rockies forests, where
> > land-use histories have relatively little effect on fire risks and are
> > strongly associated with increased spring and summer temperatures and an
> > earlier spring snowmelt.
> > ------
> >
> > Snow carries over a substantial portion of the winter precipitation that
> > falls in western mountains, releasing it more gradually in late spring
> and
> > early summer, providing an important contribution to spring and summer
> soil
> > moisture (*35*<
> http://www.sciencemag.org/cgi/content/full/313/5789/940#REF35>).
> > An earlier snowmelt can lead to an earlier, longer dry season, providing
> > greater opportunities for large fires due both to the longer period in
> which
> > ignitions could potentially occur and to the greater drying of soils and
> > vegetation. Consequently, it is not surprising that the incidence of
> > wildfires is strongly associated with snowmelt timing.
> >
> > Changes in spring and summer temperatures associated with an early
> spring
> > snowmelt come in the context of a marked trend over the period of
> analysis.
> > Regionally averaged spring and summer temperatures for 1987 to 2003 were
> > 0.87°C higher than those for 1970 to 1986. Spring and summer
> temperatures for
> > 1987 to 2003 were the warmest since the start of the record in 1895,
> with 6
> > years in the 90th percentile—the most for any 17-year period since the
> start
> > of the record in 1895 through 2003—whereas only 1 year in the preceding
> 17
> > years ranked in the 90th percentile. Likewise, 73% of early years since
> 1970
> > occurred in 1987 to 2003 (Fig.
> > 1<http://www.sciencemag.org/cgi/content/full/313/5789/940#FIG1>
> > ).
> >
> > --------
> >
> > If the average length and intensity of summer drought increases in the
> > Northern Rockies and mountains elsewhere in the western United States,
> an
> > increased frequency of large wildfires will lead to changes in forest
> > composition and reduced tree densities, thus affecting carbon pools.
> Current
> > estimates indicate that western U.S. forests are responsible for 20 to
> 40%
> > of total U.S. carbon sequestration
> > (*38*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF38>,
> > *39* <http://www.sciencemag.org/cgi/content/full/313/5789/940#REF39>).
> If
> > wildfire trends continue, at least initially, this biomass burning will
> > result in carbon release, suggesting that the forests of the western
> United
> > States may become a source of increased atmospheric carbon dioxide
> rather
> > than a sink, even under a relatively modest temperature-increase
> scenario (*
> > 38* <http://www.sciencemag.org/cgi/content/full/313/5789/940#REF38>,
> > *39*<http://www.sciencemag.org/cgi/content/full/313/5789/940#REF39>).
> > Moreover, a recent study has shown that warmer, longer growing seasons
> lead
> > to reduced CO2 uptake in high-elevation forests, particularly during
> > droughts (*40*<
> http://www.sciencemag.org/cgi/content/full/313/5789/940#REF40>).
> > Hence, the projected regional warming and consequent increase in
> wildfire
> > activity in the western United States is likely to magnify the threats
> to
> > human communities and ecosystems, and substantially increase the
> management
> > challenges in restoring forests and reducing greenhouse gas emissions.
> >
> > ------
> >
> > Vision2020 Post: Ted Moffett
> >
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.fsr.com/pipermail/vision2020/attachments/20071025/ad1c84cb/attachment-0001.html