Although it continues to be fire season in coastal Southern California, as demonstrated by the incineration of 49 homes in Malibu less than three weeks ago, the danger is dwindling throughout most of the rest of the state. Snow and rain have begun falling in the northern Sierra Nevada, and cold weather has driven humans — the primary source of wildfire ignition — to seek shelter at lower elevations.

Winter weather also will mostly bring an end to the wildfire danger in Alaska, the Rocky Mountain West, the South — pretty much everywhere except the dry Southwest, of which Southern California is geographically and climatically a part.

As fire seasons go, this was not a terrible one for California, although there were some notable exceptions: the Angora fire, which destroyed 254 homes and charred 3,100 acres of forest near Lake Tahoe; the Witch and Poomcha fires in San Diego County, which eventually merged and together destroyed 1,263 homes while charring 247,400 acres; the giant Zaca fire, which did not cause much structural damage but burned for nearly four months in the Los Padres National Forest.

But in the future, Californians are going to look back on this as having been a very good year, one in which the toll in lives altered and property damaged hardly merited mention.

There are several reasons for that. Climate change, combined with altered vegetation patterns, appears to be shifting coastal Southern California to a year-round fire season as the region grows hotter, drier and weedier. Similar changes are in store for the mountain foothills across much of the West.

But the most significant factor responsible for the scenario of future disaster is this: development in the fire zone.

In September, the Sierra Nevada Alliance released a report that attempted to quantify the risk. Using various population projections, land-use plans and assessments by public-safety agencies, the organization came up with this: By 2040, the population of the Sierra region will triple, and 94 percent of the land designated for rural residential development has been classified by the California Department of Forestry and Fire Protection as having a very high or extreme fire hazard.

This is not just a California problem, although California is the most populous state and the development pressures are greatest here. A technical report issued in August by the U.S. Forest Service's Pacific Northwest Research Station examined development projections for private lands bordering national forests and grasslands, and projected significantly increased housing density on 21.7 million acres by 2030.

These border lands — which the study defines as those within 10 miles of a national forest boundary — are among the most popular places to live because of the scenic and recreational amenities they offer. Nearly a quarter of the U.S. population lives in a county that contains national forest land.

But these border landscapes also tend to be flammable and fire-prone. And given how thinly stretched the nation's professional firefighting forces are already, there is simply no way they can defend another 20-million-plus acres of rural housing from the inevitable conflagrations, at least not without a staggering increase in personnel and resources.

Historical fire data offer additional reasons to worry.

Although there still are a few fires burning, mainly in the South, the 2007 fire season will end with about 8.9 million acres having been scorched nationwide by 83,208 wildland fires, according to the National Interagency Fire Center. That's down from last year, when 91,694 wildland fires burned 9.6 million acres. But the acreage figure for 2007 is the second-highest since 1960, and it exceeds the averages of the preceding five and 10 years by 25 percent and 29 percent, respectively.

Clearly, fire frequency and size are both increasing, a consequence of a variety of factors: a warming climate, past firefighting and logging practices, increased human incursion into the woods. Combine that trend with the population and rural development projections, and you have a prescription for holocaust.

The public purse is not bottomless, and it is not clear that even unlimited spending on personnel and equipment would be enough to save all the additional lives and homes that will soon be at risk. Absent the political will to impose tough restrictions on rural development — say, to ban it altogether in areas of high fire hazard — events such as this summer's inferno at Tahoe and last month's in Malibu will become even more routine than they already are.

— John Krist is a senior editor and Opinion columnist for The Star. To read previous columns, visit www.johnkrist.com. E-mail: jkrist@VenturaCountyStar.com.