Paul Lowenthal, a firefighter for the Santa Rosa Fire Department, was helping others evacuate the Tubbs Fire while his own home burned down. (Whitney Shefte,Alice Li/The Washington Post)

Gaye LeBaron is a columnist for the Press Democrat in Santa Rosa, Calif.

Sonoma County, Calif., is 1,550 square miles of valleys circled by coast range mountains. Two of its nine cities — the largest, Santa Rosa (population 175,000) and its neighbor to the southeast, Sonoma (population 10,600) — spent 10 days under siege from wildfires that have, at last count, destroyed 6,700 structures, most of them single-family homes.

Sonoma, once a Mexican pueblo and mission, is generally regarded as a cradle of California history.

Santa Rosa is the county seat, central to an agricultural region that has been known in the past three decades as “wine country.” It is a border town, an “edge” city, separating the densely populated San Francisco Bay Area from the rural northern counties.

Horacio Hernandez and Laura Gomez lost the two-bedroom home they rented in the Santa Rosa fire. They had no insurance and are now struggling to find a new place to live. (Whitney Shefte/The Washington Post)

It is an area with a population proud of its landscape. Citizens have allocated tax money for “forever wild” land for more than a decade. Many of the hilltops still smoldering around the towns are burning in state parkland, nature preserves and designated open spaces.

Nature had actually provided Santa Rosa with a warning that went unheeded. In 1964, a similar fire burned the same path from Calistoga in northern Napa County over the Mayacamas Mountains, along Mark West Creek, heading west and veering into a kind of wind tunnel that sped up the flames, propelling them all the way to town.

What makes this fire different is the scope of it and the fact that the ensuing half-century has placed so much development in its path.

In 1964, there were very few houses in the area that burned. As the city limits extended and the population increased by 135,000, the open land in that earlier fire corridor became a destination for developers.

Fountaingrove Ranch, directly north of the city, had been in its 100-year history a utopian community, with several hundred acres of vineyards producing prized wine. The last owner of the 2,000-acre ranch began selling off the acreage not long after the 1964 fire.

The first sale was welcomed by the town — it resulted in a campus-style complex built by computer pioneer Hewlett-Packard. The rest of the property changed hands frequently, each new owner with his own ideas — two hotels, a golf course and finally a tract of imposing two-story homes crowded on 60-by-100-foot lots. A sudden wave of regional prosperity occasioned by the arrival of a cluster of telecommunications companies brought a new, young moneyed class of homebuyers. Bigger homes were built on larger parcels in the open land to the north — land that had burned 40 years before.

While it is still closed to viewers, we know that almost all of this is gone now, leaving a core of older citizens, pioneers of the embryo environmental movement of the time, to think: “We told you it was a bad idea.”

And indeed they did. In the 1990s, when the last of Fountaingrove was being sold off, a persistent core of protesters turned up at contentious late-night hearings, arguing for preservation of the remaining ranch as parkland and against a parkway deemed necessary for easy access.

But in the eagerness to embrace this addition to the city’s economic life in the lean years of the 1990s, certain rules were overlooked, as city planners and engineers would later admit. One was a ridge-top ordinance that prohibited development on the hills surrounding the Santa Rosa Valley. It had been in place for several years but seems to have been forgotten.

We will certainly hear more about it now, and about climate change and history repeating itself, when the plans for rebuilding come before our civic leaders. The conversations have, in fact, already begun, even as the fires are still burning. Elsewhere in the country, we can expect similar conversations in Houston and in San Juan and in the next community to be visited by disaster in what has been a season of them.

The environmental movement in Sonoma County is an embryo no longer. Since the early ’90s, there has been an open-space district that funds protective land purchases. Citizens organizations such as the Land Trust, Landpaths, Conservation Action are all powerful in a county where housing was already expensive and in short supply. The political landscape has changed as much as the physical one.

We will need more wisdom going forward. Santa Rosa’s — and all of Sonoma County’s — future is at issue. The ill winds, blowing cinders in all directions and sending fireballs big enough to contain burning tree limbs across four lanes of freeway traffic, have blown us no good. But of one thing we can be certain: We have entered a before-and-after zone.

In future years we will view our history through a screen of the smoke and flames of October 2017. Things will happen “before the fire” and “after the fire” and those who are here today will understand.