By Dr. Robert Thorson

Hazard. Disaster. Catastrophe. Learning the difference between these three words can is as simple as counting 1, 2, 3, and can help you save money.

The American West is being broiled by triple-digit heat, day after day. Things are so parched that fires are burning from Arizona to the Dakotas and breaking records in Utah. Meanwhile, reservoir water levels are frighteningly low. This heat wave-tinderbox-drought is a ____?

Consider the New England shore during this hurricane season. Despite strife among employees at the U.S. National Hurricane Center, they’ve made their predictions and readied their emergency plans for this year. If and when a hurricane strikes, you should call it a _____?

New Orleans is still hurting badly, despite two years of valiant rebuilding after Hurricane Katrina. What happened there in August 2005 was a _____?

The answers to questions 1, 2, and 3 are hazard, disaster, and catastrophe, respectively.

A hazard is any danger, big or small, that might hurt something. According to Merriam-Webster’s Dictionary, the word is from Arabic, al-zahr, meaning the die or dice. Disasters and catastrophes are both actual events involving great, often sudden damage to the established order.

Disaster comes from the Latin dis + astro (star), meaning an unfavorable natural sign or a bad omen. Unlike the case of gambling, they are “fated” to happen when large groups of human beings gather in the presence of a hazard. The word catastrophe comes from the Greek, kata + strephein (to turn). Its chief connotation is an overthrow of the established order, as in the denouement of a classical tragedy, the cusp of a mathematical curve or a critical event between two periods of pre-history.

Consider the remote geologic past. The strain on tectonic plates, the pressure in a volcano or the heat of a tropical ocean are hazards manifesting as earthquakes, eruptions or drenching floods, causing major but localized death and destruction to a non-human population. Recovery follows. The system returns to normal. But under the right conditions — perhaps because the pulse of energy was extreme or because a gradually changing system had reached some tipping point — the system may not return to its previous condition, leading to catastrophe. The old order was overturned.

Across the country this autumn, geology professors (who take the long view) will be teaching their introductory students that earth history is mostly about periods of slow-steady change punctuated by catastrophic events — for example, the asteroid impact that divided the so-called Age of Reptiles from the Age of Mammals.

In a different lecture, those same professors will be describing the so-called disaster cycle, in which people inhabit places without recognizing hazards or denying their existence; the hazard manifests itself on a large population; residents are understandably anguished and astonished; blame and recrimination are misplaced; recovery leads to cultural amnesia; and disaster strikes again. This cycle occurs over … and over … and over … and over … because human beings are naturally optimistic. And like politicians everywhere, they focus on the near future, rather than the long haul.

Only the most rare natural disasters come out of nowhere. One example was the great earthquake of 1886 in Charlestown, S.C., which destroyed more than 2,000 buildings, bent miles of railroad track and killed more 60 people. In this case, the natural hazard, when combined with the human presence, created a disaster. But this disaster did not take the next step toward catastrophe.

But in the case of New Orleans, I do not believe that it will ever be business as usual. The fatal combination of a rising sea, sinking soils and two centuries of bad river and coastal management has tipped the city into catastrophe. The City of Jazz will survive, especially on what they consider high ground, thanks to the pluck and tenacity of its residents. But it will never be the same.

The most cost-effective way of dealing with natural catastrophes is to acknowledge that one has occurred, rather than label the situation as yet another disaster. The most cost-effective way of dealing with disasters is to adopt policies that encourage avoidance of known hazards — like wildfires — rather than fighting them, endlessly and expensively.