29 November 2017

Carbon Canyon, Wind and Wildfire Risk

In the wake of October's devastating wild fires in northern California, the Los Angeles Times from last Friday the 24th had this lead headline on its front page: "Fire policies sidestep key factor: wind."

Bettina Boxall's article goes on to discuss a realization made by University of Washington atmospheric scientist Cliff Mass's realization after studying a pair of high-resolution weather models on 8 October when the conflagration broke out: "Oh my God, look at he winds?  What if people were paying attention to this? What could they have done?"

Boxall continued:
As California puts more people and houses on one of the planet's most flammable landscapoes and the grim list of deadly wildfires grows longer, some experts say it's time to take stronger steps.  Among them: Ban development in wind corridors where wild lands repeatedly burn . . .
As Alexandra Syphard, a research scientist with Conservation Biology Institute notes:
In Southern California, every single year the conditions are there for a severe wildfire.  You have Santa Ana wind conditions every year.  You have summer drought every year, high temperatures.
Alex Hall, an atmospheric sciences profesor at UCLA, added:
There are certain corridors where the winds tend to travel.  We also have the ability to predict event by event where the winds are going to be the strongest. 
But with wind mapping and forecasting not shown in the wildfire policies of the State of California, the problem becomes, as Syphard expressed it:
I often hear people say that if we construct our buildings correctly and put enough defensible space around it, then we don't need to worry about where you put the houses.  But they don't necessarily fireproof your house.  You can see that by some of the houses that burned in recent years.
Despite the passage of law five years ago that requires local jurisdictions to include wildfire risk when updating general plans and approving housing projects, Boxall wrote, "there appears little inclination to place especially fire-prone areas off limits to development."

What then followed is a quote from Mitch Glaser, assistant administrator for the regional planning office in Los Angeles County: "we have to consider property rights."  He went to say that, while changes in the layout and size of housing projects are made, no denial of an application was made because of the risk of fire.

Boxall continued: "The building continues even in areas where it is virtually guaranteed that a wind-whipped fire will roar through sooner or later."  She also noted that in France there are new regulations that ban development in hazardous fire zones in the southern part of the country.  A natural resources advisor with the University of California cooperative extension system told Boxall, "it's not terribly popular.  But they do have the ability to make that happen."

This takes the matter then to local jurisdictions and land-use planning.  Richard Halsey, director of the California Chaparral Institute, commented:
Local municipalities are so concerned about their tax base and private property rights and making money that they're not addressing the real risks.
He recommends barring development in high-risk locations or, if it is done, then requiring residents to sign waivers that they forego fire protection, though he followed by stating "I don't know if politically that's ever going to happen."

The article also addressed above-ground power lines and the addition of weather observation stations on poles or requiring that lines be routed underground (which is a significant expense and, in some cases, difficult with terrain).  Shutting off power for public safety reasons was also discussed.

Notably, what San Diego Gas and Electric has found in its monitoring of wind in a county that has been heavily affected by wildfires in recent years is that "it turns out the county's strongest winds don't blow through passes or canyons, as previous thought . . . [and there is] remarkable variability in wind strength across relatively short distances."

In 2014, a new program with that utility, the U.S. Forest Service and UCLA was launched and the Santa Ana Wildfire Threat Index is intended to rank threats based on weather and moisture in vegetation.  At the end of October, "one of the strongest Santa Ana events in years hit Southern California" and the ranking was high, just below the worse of extreme.

For Carbon Canyon, this article has great relevance.  While District 12 of CalTrans on the Orange County side of the canyon put up signs several years ago noting an extreme fire hazard, this designation was not made for the San Bernardino County side by District 8.  A wildfire, however, won't heed the sign difference and stop burning at the county line.

Moreover, while San Diego's experience is that the strongest winds may not be in canyons and passes, that in no way suggest that these areas don't funnel high winds and pose great risks.  They certainly do, as most recently was demonstrated in another pair of destructive Santa Ana Canyon fires in September and October and as the history of wildfires has shown in Carbon Canyon (1929, 1958, 1978, 1990 and 2008 being just the worst of many such conflagrations.)

A United States Geological Survey video "Living with Wildfire," which was the subject of a post here a few years ago, warns of high winds at upper elevations as well as gullies and other natural features serving as funnels for winds up from canyons to those plateaus and ridges on adjacent hills.

Private property rights, property tax revenues and other factors will continue to influence decision-making at the local level, but these will be dwarfed by the financial and human cost of catastrophic wildfires, the intensity and frequency of which are growing.

Our local officials in city and county government and in fire-fighting will continue to face these issues and articles like this as well as the USGS video, in addition to mounting studies of wildfire conditions and causes, will, hopefully, bring more needed attention to a growing problem.

After all, most of the remaining undeveloped land in our region are in our canyons and hills—precisely those areas most in danger of extreme wildfire risk.  The Hillcrest project of 76 units is slowly progressing on the north side of Carbon Canyon just east of Sleepy Hollow and the subdivision is surrounded by wildfire-prone areas with many homes at the ridge top and plateaus where winds are strong, carrying embers well over the defensible spaces put into the project.

Across Carbon Canyon Road, directly south of Hillcrest, the proposed Hidden Oaks, of over 100 units, will soon be heard by the city's planning commission and council.  Again, the project is sited on hillsides, plateaus and ridges with steep topography to Soquel Canyon on the south and Chino Hills State Park (98% of which burned in 2008) beyond that.  Many home sites are, once more, in higher elevation with strong winds.

It is likely that city staff will cite private property rights, future revenue, and improvements in planning for fire as reasons for approving the project, even as our knowledge of the issues with the risk of wildfire grows.  Unfortunately, prospective buyers will not be made aware of that risk and will be lulled into a sense of false security when they move into these new subdivisions.


Richard Halsey said...

Thanks for posting this analysis of the article. You did an excellent job.

Another option that should always be mentioned when trying to reduce the risk of home ignition is the installation of external sprinklers. Wetting structures and the immediate, surrounding space makes it nearly impossible for a home to ignite during a fast moving chaparral fire.

P.S. A minor typo you might want to fix: "I don't know if politically that's every going to happen."

"every" should be "ever."

prs said...

Thanks, Richard, for the comment--interesting about the external sprinklers aspect. Also, I changed the typo--thanks for the catch!