Risk Assessment

Tornado - a low but real risk in Oregon. Photography by Juergen Pohl.

Tornado – a low but real risk in Oregon. Photography by Juergen Pohl.

Hurricanes, tornadoes, droughts, floods, earthquakes – Mother Nature sometimes seems determined to get us. Throw in a dash of humans with explosions, crashes, and even chemical warfare, and it might feel a tad overwhelming. Hazards are lurking around every corner. But don’t crawl in a hole and never come out – at least not yet. First try some perspective and figure out what your risks really are! If you do emergency preparedness at any level (even just for your family or neighborhood), it helps to understand the process of analyzing hazards and risks.

You can pick your favorite acronym – Hazard Vulnerability Analysis (HVA), Hazard Identification and Risk Assessment (HIRA), or Homeland Security’s most recent guide – Threat and Hazard Identification and Risk Assessment (THIRA – it’s not even in the FEMA acronym book yet). Despite fancy names, they are all methods of risk assessment – a basically simple idea. You sort through a huge list of bad things and choose the ones with the greatest chance of harming “you”. “You” might be a family, a community, a hospital, a business, or governmental group – depending on the hat you wear during your risk assessment. The same concept works for everyone, although your final list will vary, depending on who and where “you” are.

Warning: disaster risk language gets confusing – like many other areas of official emergency preparedness! People use many of these words interchangeably in everyday speech, yet in “disaster talk”, they sometimes have specific meanings. There’s even an official Department of Homeland Security Risk Lexicon. To make matters worse, official definitions change with time, but changes may not fully filter down.  Bottom line – when nuances of meaning matter (like in written documents), you probably should define terms. But for practical purposes, it’s the ideas, not the actual words which count.

THIRAHazards and Threats

A hazard is anything that could harm humans or the environment, so start your risk assessment by making a hazard list. At this step, a bigger list is better. Consider dividing your hazards into natural causes (like earthquake faults and storms), accidental (like chemical spills or crashes), or intentional (like active shooters or terrorism). I find these categories help prompt my thought process. You even get combos like the Fukushima nuclear problems after the 2011 Japan earthquake – an accidental hazard as a result of a natural hazard.

This is a good example of “people on top” deciding we need a language change. In THIRA, they call accidental hazards “technological” and intentional hazards “human-caused”. This doesn’t make sense to me – last time I checked, humans still cause most accidents! Don’t you love semantics (and wonder at political motivations)? I will be good and try to use the newer terms here, even though I find the old ones more helpful!

A hazard is just something that might go wrong. It has to cause harm before you get an emergency or disaster (depending on how big and bad it is). Every disaster is caused by a hazard (even if the hazard wasn’t recognized in advance), but not every hazard causes a disaster. For example, at our recent Steam-Up event, we had hazards galore with antique steam engines, a blacksmith shop, a saw mill, cannons, and crowds of people. However, there were no disasters, and no major emergencies.

Antique Steam Tractor. Photography by Sheila Sund.

Antique Steam Tractor. Photography by Sheila Sund.

So what’s  the difference between a hazard and a threat? “Attention. The Homeland Security threat level currently is at orange.” Theoretically, the word “threat” means a hazard directed somewhere specific, like a hurricane threatening Miami.  It’s also used for the likelihood that a hazard will actually occur.  However, the use of “threat” to imply terrorism is so pervasive that many people think of it only in those terms. In the new THIRA guide, the words threats and hazards are always stated together (perhaps because of the confusion?) – thus the new “Threat and Hazard” title. To figure out what someone means by “threat”, you really have to look at context.

Probability

So now that you have your Big Book of Hazards, it’s time to narrow it down to the ones that might actually happen to “you”. Probability is used to guesstimate the chance that a hazard will cause a disaster in your area. Overall, I have two rules for hazard probability. 1) Refer to experts. Probability is complicated and the experts are the only ones who understand all the factors for their favorite hazard! 2) Distrust probability based primarily on human history!

People like to focus on history – how often something happened before. It creates a comforting yet often completely false security (“it never happened here before, so it never will”).  Historical records might help some predictions, such as general locations for high frequency natural hazards (the Midwest for tornadoes or California for earthquakes). However, for low-frequency natural hazards (like most earthquakes and volcanoes), recorded human history in America is a few hundred years – a tiny blip on Mother Nature’s scale. Even if something hasn’t happened in the last 200 years, it might still be likely in the next 200 years, or 10 years …or tomorrow. Geologic history and science, not human history, determine probability for most natural hazards.

Timeline - Cascadia Earthquakes

History is even unreliable for technological and human-caused hazards, because changes in human behavior will change hazard probability. Improved safety standards have drastically lowered the likelihood of technological hazards like building fires and plane crashes. On the other hand, political situations might increase human-caused hazards literally overnight. Human behavior sometimes even effects the chance of natural hazards. Media speculates daily about climate change effects on storms, floods, and drought. Pandemic risk dropped last century with improved human knowledge of disease, treatment, and hygiene. These days, global travel and drug resistant organisms may be taking pandemic probability back in the opposite direction.

Even probability math is complicated. 100 year floods don’t happen every 100 years – instead their probability is 1% every year. They might even happen two years in a row, instead of 100 years apart. Bottom line – to find probabilities for your hazard list, you need outside help. If it is a topic you like, consult expert sources (the preferred method for disaster geeks like me).

For most people, there’s a short cut. Simply find your city or county hazard vulnerability analysis – some are on-line, and most should be available for the asking. Local government does the research and identifies probabilities for all local hazards – you can just borrow from them. If the chance of a hazard is low or non-existent in your area, just cross it off your list. It’s not worth worrying about.

Vulnerability

By now, your list should only have hazards that are probable for your area. Next, think about how the hazards could affect you. Vulnerability considers how well or how poorly protected you are against a specific hazard. It also helps you guess how long it might take to recover from a disaster. Vulnerability helps prioritize your hazard list.

There are many vulnerability factors, with location being the most obvious. If floods are high probability in your area, but you live on a hill, your vulnerability is obviously less. But don’t get tricked into thinking location is everything. You won’t be flooded on a hill. But what if water, power, and medical care come from a town in the flood plain below? It sounds like you are still partially vulnerable to flood!

Broken bridge. Photo by NH53.

Broken bridge. Photo by NH53.

Just like probability, humans can change vulnerability for better or worse. Retrofitting a bridge or a building = less vulnerability to earthquakes and flood. Building codes that allow increased seaside construction = increased vulnerability to storms and tsunamis. The good news is that any emergency preparedness decreases vulnerability, whether by families, neighborhoods, businesses, or community. Hazards with high vulnerability should obviously be higher on your list!

Impact

Finally there is impact – the greatest factor in my mind. How bad can a hazard get – not just for you, but for your entire community? After all, we depend on each other. I’m a worst case scenario kind of gal. High impact disasters move high up on my list, even if they are not the most probable. By planning for the worst, I figure anything else will seem easy in comparison.

Vulnerability is definitely part of impact – the more vulnerable you are, the greater the impact. However, impact also reflects the potential severity of the disaster. When our Cascadia earthquake hits, the impact in the Pacific Northwest will be immense, no matter where your house is or how much mitigation we’ve done! Similarly, if you are in the direct path of a F5 tornado, you are going down – i.e. high impact!

There are many things to consider in estimating impact. Geographical size is key – how large an area will the hazard affect? Will it affect a single building (fires), a few blocks (chemical spills), a city (floods), the entire state (Cascadia), or the nation (pandemic)? Size not only influences the number of people and buildings affected, but also the availability of outside resources, and even the possibility of evacuation. Look at potential impact on infrastructure – power, water, communications, and transportation. Will you lose electricity? Are generators and fuel available? Will water systems shut down or suffer contamination? Do other water sources exist (more likely in the Pacific Northwest than in New Mexico)? Will phones and internet function? Don’t forget transportation. When roads and bridges are out, emergency personnel can’t reach fires or injured, and outside assistance may have difficulty reaching you. You could also get stuck far from home. We have lots of rivers in Oregon – if bridges go down, it may take days to find a way across! Predicted recovery time also influences impact. Power outage for three days might be handled by generators and stored fuel, but after that, fuel distribution could become a logistical nightmare.

Haiti Earthquake - High Impact, High Vulnerability. Photo by United Nations Development Programme.

Haiti Earthquake – High Impact, High Vulnerability. Photo by United Nations Development Programme.

The potential impacts of a hazard also depend on who “you” represent. For family risk assessment, I worry about impact on basic needs like shelter, food, and water, as well as communications and ability to reunite. Business risk assessment looks at risks to employee and customer safety during a disaster, but also considers whether the business can still function after the disaster.

I’m assisting with a six county hazard vulnerability analysis for our healthcare preparedness region. Our discussions look at healthcare impacts of potential hazards, including inpatient and outpatient medical surge, patient transportation, medications, and supplies. Power, communications, and water outages obviously play a huge role, but our focus is how they affect healthcare operations.

Putting It All Together

Using the steps above, you start with a list of all potential “hazards and threats” for your area. Ideally, break your hazards into three groups – natural, technological, and human-caused. Then cull your list based on probability. Do research, or refer to local hazard assessments, and cross off hazards with a low probability of affecting “you”.

Now comes the hard part. Try to arrange your hazards in priority order, based on some combination of probability, vulnerability and potential impact.  “Easy” hazards are high probability, high vulnerability, and high impact – obviously these go on the top of your list (the Cascadia earthquake heads most western Oregon lists). Similarly, low probability, low vulnerability, and low impact hazards go to the bottom (for example, heat waves aren’t a big problem for Oregon – at least not yet). The difficult question is what to do with middle level hazards. How do you balance different levels of probability, impact, and vulnerability to prioritize these hazards?

Driving through flood waters (do not attempt this at home!). Photo by DVIDSHUB.

Driving through flood waters (do not attempt this at home!). Photo by DVIDSHUB.

It again helps to remind yourself about which hat you wear. Vulnerabilities and impact specific to your role often make certain hazards stand out from the crowd. Our healthcare region chose pandemic as our second highest hazard, although it doesn’t even appear on some county emergency plans. From a healthcare perspective, it obviously has high potential impact on patient care, despite fairly low impact on factors like infrastructure and property. Pandemic seems reasonably likely, and we are definitely not well prepared (high vulnerability)!

When I wear my family hat, floods are low on my list. I live in the hills, use well water, and rarely work, travel, or shop in flood zones. However, wearing a county emergency hat, I would move floods near the top. Marion County has large flood zones, with the potential to displace many households, and interrupt power, water, and transportation throughout the county.

Hazard Vulnerability Models

There are a multitude of hazard vulnerability analysis tools on-line, often directed to groups like healthcare or business. Many assign scores to each hazard, often through complicated formulas where you rate probability, vulnerability, and impact, then multiply by different weight factors. After reading numerous HVAs, I’m not convinced the models result in better lists than an educated discussion of the factors outlined above. Even though numerical scores sound impressive, remember they are still subjective (because your ratings were subjective). However, if the concept of a model sounds appealing to you, you’ll have no difficulty finding one, although I have no idea how to determine the best one. None of them rise to the top in my mind.  In any case, check your final hazard list against your gut feeling. If the two don’t correlate, you might want to do some more research.

Ultimately, there are no right or wrong answers for the priority order of your hazards. Like many things in emergency planning, the greatest benefit comes from the process of analyzing your hazards, not the final product or list.

Why Bother with Hazard Vulnerability Analysis?

Raising the dike - North Dakota floods. Photo: Michael Rieger/FEMA.

Raising the dike – North Dakota floods. Photo: Michael Rieger/FEMA.

So you have a list. Now what? At least you have a focus for your worries, and maybe you found a few things to forget about. You can put your fears in perspective, and not crawl in a hole. You might even sleep better at night. But the real reason for a prioritized hazard list isn’t improving insomnia! Your hazard vulnerability assessment should direct emergency preparedness efforts – what you spend your time and money on. In fact, many grants require both a HVA and a reason why the award would addresses the top hazards. Alas – another blog topic for another day!

Stay safe,

Sheila Sund, M.D.