Correction: An earlier version of this piece misstated that the simulation Pam tested the vulnerability of New Orleans to a major earthquake. It actually tested the city’s vulnerability to a major hurricane.

This semester, as fires raged just south of where I teach in Chico, Calif., I taught a course on the history of catastrophes. The catastrophic fires that have devastated California communities have become part of that history, and as such, there are valuable lessons we can apply to the fires. As students in the class learned, disasters follow certain patterns: denial, panic, scapegoating, grieving. Social solidarity often increases momentarily, only to later decline sharply.

Knowing these patterns can help us understand, and to a certain extent predict, the way a catastrophe will unfold. That knowledge can help us better respond to the long-term effects of catastrophes like the California fires, especially as public attention fades and solidarity declines.

First, there is denial. Perhaps the most famous example of catastrophe denial was immortalized by Thomas Mann in his novella “Death in Venice.” Mann describes an actual incident in 1911 when Italian officials, worried about the tourist trade and concerned about the prestige of the fragile Italian state, denied that a cholera epidemic was taking place in Venice.

Likewise, many in Northern California denied that the wildfires would affect them. The City Council in Paradise, where devastating fires occurred in 2008, voted in 2014 to narrow the main access road to increase foot traffic downtown, a choice that made escape from the Camp Fire difficult. Local authorities chose not to make use of the federal government’s Wireless Emergency Alert system, and their own system failed to reach much of the city before it was too late for many elderly citizens.

Panic is the next common stage in a catastrophe: wealthy Europeans fleeing the cities during the Black Death in the 14th century, Irish emigrants boarding unsafe ships for Liverpool and eventually North America during the potato famine, Tutsi refugees streaming out of Rwanda in 1994. The scenes were similar in Sacramento this year: long lines of vehicles, packed with belongings, disgorging refugees. But this option was not available to those without cars or those who could not afford the prices that motels were charging. In all these cases, it was the comparatively well-off who could afford to evacuate; the indigent and immobile were left to face the worst consequences.

Then there is scapegoating, potentially the most divisive reaction in a catastrophe. At the time of the Black Death, the Brotherhood of the Flagellants massacred Jewish communities in Germany and elsewhere, blaming them for the plague. As a result, a great many Jewish survivors migrated to Eastern Europe. English elites tended to blame the alleged moral turpitude of the poor for the outbreak of cholera in London in the 1850s. They reasoned that the death of so many poor and working-class people in the Soho district was due in part to their fragile constitutions, weakened by alcoholism, idleness and general lack of proper bourgeois values.

In the case of the Camp Fire, rumors circulated that a homeless person had started the fire by accident, thus tapping into an emotional local debate on how to deal with the homeless population. Then Pacific Gas & Electric was accused of negligence regarding its power lines, and law firms are lining up clients to sue the company. Unwilling to mention climate change as the likely culprit for the recent megafires in California, President Trump, during his brief visit, chose to place the blame on insufficient sweeping of our forests.

The fourth stage is solidarity. Ethnic and class differences momentarily evaporate as “disaster communities” emerge spontaneously, working alongside government and private disaster agencies to offer what relief they can. Rebecca Solnit in “A Paradise Built in Hell” argues that in the wake of Hurricane Katrina, grass-roots organizations such as Common Ground and various church groups provided relief more immediately than did official agencies, often mired in red tape. The very day the fire broke out, people in Chico and the surrounding communities began collecting and distributing supplies, organizing shelters, volunteering countless hours, offering evacuees refuge in their homes and donating money. My university responded nimbly, raising close to $400,000 of emergency funds for affected students in less than two weeks.

But the tsunami in the Indian Ocean demonstrates how a momentary wave of altruism was replaced by a bitter struggle over the “golden wave” of financial aid, resurrecting and exacerbating social divisions. During the potato famine, poor-relief officials had to make life-or-death decisions about who was admitted to a workhouse, decisions that were often swayed by issues of social class.

In California, there are already reports of unscrupulous real estate speculation, law firms fishing for clients and price gouging. The serious homeless problem is likely to be aggravated as the more affluent evacuees find housing, leaving a residual impoverished population either continuing to reside in the tent city evacuation centers or moving into the streets if they cannot leave the state.

We also need to better understand how societies learn from catastrophes. In the wake of the great influenza pandemic of 1918-1919, which may have killed as much as 5 percent of the world’s population, the American medical establishment awoke from its complacency, concentrated on the problem of viral epidemics, established the National Institutes of Health and increased the rigor of medical school education.

But lessons from previous disasters are not always effectively learned. Less than a year before Katrina struck New Orleans, an elaborate simulation code-named Pam had shown how vulnerable the city was to a major hurricane, but its lessons were ignored until it was too late. No effort was made, for example, to shore up the levees, which ultimately failed and left the city vulnerable to devastating floods.

Should Paradise be rebuilt, what lessons will be learned from this disaster? Will zoning laws require home construction in insulated concrete forms, which are much more resistant to fire than wood? Will Pacific Gas & Electric be persuaded to bury power lines? Will an early warning system be established? Or will the need for cheap housing and the fetishization of the free market lead to the same old pattern?

One factor that will shape the long-term response to the Camp Fire is how California chooses to remember this disaster. Societies grieve catastrophes in different ways, all of which lead to different outcomes. Some countries memorialize a catastrophe as the foundation of a national identity: the potato famine for Ireland, the Gallipoli campaign for Australia, the Holocaust for Israel. On the other hand, I am not aware of any memorials to the victims of the influenza pandemic, which killed many more people than did World War I. Yet many of those people could have been saved, at least in Europe and North America, if proper quarantine methods had been implemented. So, in a way, they are as much the casualties of government decisions as the dead of the war.

The number of certified deaths in the Camp Fire — of people who endured the horrible death of being burned alive — stands at 85 but may climb higher. If the town is rebuilt, will these people be commemorated or forgotten?

Much of what we study in my class is remote in time — the Black Death, the Irish potato famine. But the 2004 tsunami, Hurricane Katrina and now the California fires remind us that catastrophes are not a thing of the past, nor are they experiences limited to developing nations. Catastrophes are a constant, but by understanding them, those of us in California and beyond can be better prepared for the long process of recovery that lies ahead.