Thursday, November 15

Argument: Loss of forest windbreaks major cause of huge N. California wildfires

Paradise is situated in a wind tunnel that didn't exist when the town was built in the 1870s. It was this wind tunnel that within moments whipped a small brush fire into a fast-moving inferno, which all but destroyed Paradise within a few hours on November 8, 2018. Since then, discussions about the leading reasons for the "Camp" fire disaster have not gone near addressing what I'd argue is the key reason.

An established, well-acknowledged fact is that northern California has over decades lost much of its forest.(1) What is not acknowledged in discussions about California's wildfires is that forests act as a powerful windbreak -- even though this is also established fact.(2) So, no connection has been made between the loss of windbreak due to loss of forest and the high-velocity winds that fueled the Camp fire.     

Yet it was the forest windbreaks that had kept fierce winds, which routinely arise from the Great Basin, at a more docile pace in the region. Then destruction of the north's forests reached a tipping point, perhaps as late as the turn of this century, and so they can no longer adequately protect the region from the Diablo winds, as they're called in the state's north (Santa Ana in the south). 

These winds are not really seasonable, or they're no longer seasonable, because they are blowing for 10 months out of the year to a greater or lessor degree:

So with greatly reduced windbreaks, northern California's climate would have to turn tropical to offset the nearly year-round drying effect of the Diablo winds! I think this shows the flaw in explanations that California's heavy rainfall earlier in the year, followed by six months without rain, created huge amounts of bone-dry tinder that fueled the Camp fire. With the Diablo winds blowing, I'd think it would take only a couple weeks, if that, after the rains ended to turn damp vegetation into tinder.

Californians don't have to wait for scientific studies to confirm my argument. They can just ask themselves whether people would build a town in a wind tunnel situated in Forest Fire Alley. 

Paradise was established on a ridge in the Sierra Nevada foothills in the 1870s along a railway that served mining and sawmills. The region was so heavily forested that the town seal shows a big tree and the city flag features a dense treeline. Forest fires, usually due to dry lighting strikes, were common. But there is no way they traveled at 70 mph, as winds were clocked shortly before the Camp fire broke out. If that had been the case Paradise could easily have burned down several times over since it was established.

If you entertain my argument for the sake of discussion, what about solutions? I doubt the massive forests could be restored in our lifetimes. So what Californians would be left with is a search for offsets; that's first a job for mathematicians, engineers and researchers working on wind-related problems, and plant specialists.  

The idea is to learn what kind of fast-growing vegetation can produce enough drag friction to slow winds that are often near Category 1 hurricane force. Then identify where the vegetation should be planted for best effect against the winds. Then plant the vegetation in whatever amount and configuration the specialists advise. As to getting the water for the plantings -- I see no offsets that do not involve financial pain for Californians.   

As to building completely artificial windbreaks in large enough number to slow the winds without making the region unlivable, that's also a question for specialists.

But you can't start working on offsets until you narrow the field. Californians seem to be more focused on climate as a monolithic, global phenomenon than on microclimates. Yet California has several widely varying microclimates. Until the voters there think first in terms of microclimates -- their own -- I don't see how they can move off the dime of their present assessments of the state's wildfire disasters, which have not led to viable offsets.

A big question for me is whether the loss and attendant increase in the velocity of Diablo winds are altering the microclimate in the state's north -- changing it from very moist to drier. I believe there's a case to be made for this although we must wait on more data, which might mean waiting for more years to pass. 

Another question is whether massive loss of forest in the north is affecting climates in the more southern areas of the state and even in other U.S. states. I know that some research has already been done on the latter aspect. See California Tree Loss Could Have Implications for Forests Nationwide, which includes this sobering claim:
"Forest loss [on the West Coast] is disrupting or changing the flow patterns in the atmosphere that is leading to a slightly different summertime climate in the eastern part of the country." 
In summary, I'd say to focus more on the Diablo/Santa Ana winds when devising responses to California's wind-driven wildfires. Don't accept the winds' high velocity as an unavoidable permanent fixture of California life that has always been the case. Common sense alone tells this has not always been the case, at least not in the state's north.

1) Pot Growers Destroying National Forests (2011, Live Science)

26 Million Trees Died in California Forests in Just One Year (2016, TakePart)

2) "The severe drag-friction over forests absorbs energy and slows down winds."
-- Douglas Sheil, "Forests Versus Hurricanes"

"Windbreaks are barriers used to reduce and redirect wind. They usually consist of trees and shrubs but also may be perennial or annual crops and grasses, fences, or other materials. The reduction in wind speed behind a windbreak modifies the environmental conditions or microclimate in this sheltered zone."
-- University of Nebraska, Lincoln Extension, "How Windbreaks Work"

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