Extreme Weather

Weekend Tornadoes, Storm Damage, and Insurance Coverage

All good things must come to an end. After almost four months of relatively quiescent weather, the 2014 tornado season kicked off quickly and tragically over the weekend.

Vilonia, AR tornado damage (Danny Johnston/AP photo)

Vilonia, AR tornado damage (Danny Johnston/AP photo)

On Friday evening, the year’s first intense tornado (defined as an EF3 or stronger) touched down in Chowan County North Carolina, killing an 11-month old child who was trapped beneath the debris of his home. That storm brought to an end two record-breaking streaks of benign weather, marking both the latest calendar date for a year’s first EF3 tornado as well as the latest calendar date for a year’s first tornado death.

Only two days later, on Sunday, April 27th, an outbreak of severe storms spawned multiple tornadoes that killed 16 people in Oklahoma and Arkansas. The most substantial damage occurred in central Arkansas, where an 80-mile-long path of destruction swept through northern Little Rock, leaving damage reportedly indicative of an EF3 or stronger tornado. The same slow-moving severe weather system hammered Mississippi, Alabama, and Tennessee on Monday and is expected to continue bringing dangerous weather, including the possibility of strong tornadoes, to the southeastern US through at least Wednesday.

Storm Prediction Center convective outlook for 29 April 2014

Storm Prediction Center convective outlook for 29 April 2014

Although intense tornadoes are relatively rare, accounting for approximately 5% of all tornadoes nationally, they are responsible for a disproportionate 75% of all tornado fatalities (statistics for North Carolina). While each tornado fatality is tragic, tornado deaths have been generally declining in the US since the 1920’s, with an average of 80 people killed each year by tornado activity.

Tornado Fatalities 1875 - 2010 (credit NOAA)

Tornado Fatalities 1875 – 2010 (credit NOAA)

Although the majority of tornado damage and fatalities are attributable to rare intense tornadoes, even much more common weak tornadoes and severe straight-line winds can cause substantial damage to property, felling trees, removing shingles and siding from homes, and flinging debris into structures and vehicles. Most homeowners insurance covers storm damage, including damage caused by wind, hail, lightning, debris, and falling trees. One notable coverage exception found in almost all insurance policies, however, is storm-induced flooding, including street flooding, storm surge, and areal flooding due to rising rivers, streams, and creeks. For such coverage, a separate flood insurance policy is required.

In some cases, though, street flooding is caused not by an exceptional storm (i.e. an “act of God”) but rather by an insufficient storm water drainage system. In such instances, liability for damages may rest with the planning or maintenance authority responsible for the storm water system, rather than with the homeowner.

Storm water sewer overflow (photo bwsc.org)

Storm water sewer overflow (photo bwsc.org)

If a neighborhood or section of a neighborhood regularly floods, even during normal, everyday storms, the drainage system may be deficient. A forensic meteorological analysis (like this one from BSMS) of known storm events that led to street flooding, considered in the context of the local rainfall climatology, can reveal whether the drainage system was adequately designed and maintained to handle foreseeable events.

In addition to flood damage, homeowners insurance will not cover damage caused by a lack of proper maintenance. Occasionally, negligence may be suspected as a contributing factor to storm damage, leading to a denial of claim, even when it is not immediately clear whether damage would have still occurred with proper maintenance.

Storm damage

Storm damage

For instance, if a tree falls during a storm and is later found to be rotten, the insurer may deny the homeowner’s claim, insisting instead that negligence on the owner’s part (failing to remove a rotten tree) caused the tree to fall, rather than the storm. Such insurance disputes can lead to nasty legal battles. Investigation as to whether the homeowner knew or suspected that the tree was rotten (i.e. whether he or she was on notice), examination of other damage throughout the area (did healthy trees of a similar size fall nearby during the same storm?), as well as a forensic meteorological analysis (were wind speeds with the storm sufficient to fell a healthy tree of that size? did heavy rainfall and saturated soils reduce the root stability of the tree?) can greatly assist in determining the ultimate cause of the damage and thereby assist in settling such disputes.

So, the bottom line is this: storm season is here, and after a late start, it appears to be making up for lost time (at least at the moment). Extreme weather, which includes severe local storms as well as tropical cyclones, droughts, heat waves, areal flooding, wildfires, and winter storms, causes tens to hundreds of billions of dollars in damage annually in the US.

Extreme Weather Damage Costs - Smith and Katz 2013

Severe local storms are, on average, responsible for more than 10% of all damages, with tropical cyclones and droughts/heat waves responsible for nearly 50% and 25%, respectively. While severe local storms are not responsible for the largest percentage of damage costs, they do represent the most common/frequent type of extreme weather experienced in the United States, and almost everyone, at some point, will experience storm damage. Make sure you understand your property insurance policy, including any exceptions, and take care of any nagging maintenance issues (like rotten trees or loose roof shingles) that could jeopardize a storm-related insurance claim.

In the event that you do find yourself in a weather-related insurance or legal dispute, whether as the insured or the insurer, the plaintiff or the defendant, do not hesitate to contact Blue Skies Meteorological Services. We will gladly provide a complimentary consultation to discuss how a forensic meteorological analysis could determine the role that the weather played in your case and how such an analysis could facilitate an advantageous resolution of the dispute.

Next time: Weather-impacted automobile accidents

Climate Change and Security

On February 16th of this year, Secretary of State John Kerry spoke in Jakarta, Indonesia, and issued a dire warning about the security risks posed by anthropogenic climate change (aka “global warming”). In his remarks, Sec. Kerry referred to climate change as a threat to national and international security on par with terrorism and weapons of mass destruction. For those remarks, he received swift and abundant political criticism.

Six weeks later, the IPCC released its updated report, “Climate Change 2014: Impacts, Adaptation, and Vulnerability,” which states, in no uncertain terms, that climate change is already occurring and that the world is not prepared to effectively deal with the impacts .


Despite the scientific consensus on the causes and the physical, economic, and societal consequences of climate change — further reinforced by the latest IPCC report — climate change remains a strongly politicized issue in the US, with large portions of the American public and their elected officials flat out denying that human activity is causing the Earth’s climate to shift in dangerous ways. The political response was not surprising.

What might be surprising to many people, however, is where the criticism over Mr. Kerry’s remarks and the latest IPCC report did not come from. It did not come from the US military – an organization intimately familiar with the sort of national and international security issues to which Sec. Kerry compared the threat from anthropogenic climate change (ACC). The reason for this lack of criticism is simple: John Kerry and the latest IPCC report did not say anything that the US military didn’t already know. For almost as long as politicians have been debating the reality of climate change, military leaders have been studying and preparing to deal with its consequences. The same is true for a growing but still grossly inadequate number of national and international business and industry leaders.


That is perhaps a bit surprising. The leaders in climate change adaptation and response are not the elected officials shouting so loudly in Washington DC, but rather the US military and a number of businesses that have been quietly but steadily making preparations for years. The fact that both of these communities – military and business – are traditionally considered quite conservative points to the fact that climate change is not fundamentally a political issue – it is not an argument about opinion, because decades of climate science have firmly established the basic facts. It is instead a practical issue, one that places in sharp relief the realization that, despite our tremendous technology, we human beings are still critically dependent on the weather and climate in which we live.

As far back as 2003 (and likely even earlier), the Department of Defense was considering the security implications of and adaptation strategies for anthropogenic climate change, including both abrupt and gradual change scenarios. The adaptation and mitigation strategies being considered and implemented include not only plans and contingencies for dealing with the political upheaval, famine, water shortages, mass refugee movements, and natural disasters that are expected to be induced by climate change but also plans for reducing the military’s non-renewable resource usage and greenhouse gas emissions.


While some uncertainty remains in the details of climate change impacts, the basic impacts like increases in extreme temperature and precipitation events, ecosystem shifts, disruptions to food production and water supply, and rising sea levels are well understood and known with high confidence. The uncertainty in the details can pose substantial challenges for effective adaptation planning, though. When you don’t know exactly how much, exactly when, and exactly where the impacts will be felt, estimation and bet-hedging are inevitable and necessary. Planning for the absolute worst is expensive and may not be necessary in the end, but simply hoping for the best could lead to a disaster of under-preparedness.

drought-07-Jay Janner

Of course, if we wait until all of the details become crystal clear and well constrained, it will be too late and far too expensive to effectively adapt. So smart players hedge their bets. They study their exposure and vulnerability to known and likely climate change impacts. They assess their risk. And they take action.

Some local and regional businesses may be understandably wary of spending money to prepare for something that “isn’t absolutely certain,” but keep in mind that we prepare for things that aren’t absolutely certain all the time.

Along the coast, we buy and keep plywood in our garages and stocks of canned food in our pantries for hurricane season, even though most of us won’t see more than a bit of tropical rain in any given season (and will end up eating lots of canned food to clear shelf space come October and November). In the Midwest, we build basements and safe-rooms to shelter us from tornadoes, even though most of us will never be hit by a twister. We buy insurance, and commodities futures, and keep money in the bank “just in case”.

We do this not because we’re certain that we’ll win the bet, but because it would be so much worse to lose the bet without hedging, without preparing. We seek security and resilience by acknowledging and adapting to risk.


So when the Department of Defense, Coca Cola, Levi Straus, Swiss Re, and other major players start creating and enacting climate change adaptation and mitigation plans, it’s time for the rest of us to take notice.

Climate change is real, it’s already happening, and it’s almost certainly going to get worse. How much worse is the trillion-dollar question and is largely within our control, should we choose to exercise it. We (as a species, as a collection of nations and communities) can choose how we adapt to the warming that’s already built into our climate system due to the past 150 years of industrial emissions, and we can choose how and by how much we reduce our greenhouse gas emissions to mitigate future climatic changes.

Despite the political overtones that stubbornly persist in the US, climate change is not a fundamentally political issue, and we treat it as such only at our peril. It is a practical, economic, and human issue for which pro-active planning, adaptation, and mitigation are the only reasonable responses. Ignoring climate change or denying it only amplifies the challenges that we face.

The first step toward building climate change resiliency is understanding the risks. Blue Skies Meteorological Services can help businesses identify their exposure and vulnerability to climate change impacts so that risks can be effectively targeted and reduced while resiliency is simultaneously built into operations.

El Niño On Its Way for End of 2014?

After several relatively quiet years in the equatorial Pacific Ocean, El Niño may be on its way back.

A new research study published in the Proceedings of the National Academy of Sciences (PNAS, February 2014) utilized a novel, long-range statistical approach to El Niño forecasting and found a 75% likelihood that El Niño conditions will begin to present by the end of 2014.

El Niño is the warm phase of a larger ocean-atmosphere cycle called the El Niño Southern Oscillation (ENSO). During an El Niño event, the waters of the eastern equatorial Pacific off the coast of Central and South America become anomalously warm. During the opposite phase of the cycle, La Niña, those same waters become anomalously cold (see figure at right, credit: NASA).


This fluctuation in water temperature may seem like a relatively localized phenomenon, but because the ocean and atmosphere are coupled (interconnected) and circulate the entire globe, an increase in water temperatures off the coast of Peru is not only devastating to the local fishing industry, but is also the most important driver of natural interannual climate variability across the entire planet.

Globally, El Niño conditions result in a major shift in atmospheric circulations and, consequently, weather patterns (see figure below right, credit: NOAA), as well as an increase in globally averaged temperatures.

In the northern hemisphere, El Niño conditions typically result in

  • Stronger, more frequent storms affecting the southern US, especially during winter, due to a more vigorous and more southerly subtropical jet stream
  • Warmer than normal temperatures throughout the northern US, southern and western Canada, and Alaska
  • Drier upper Midwest in the US

ENSO conditions in N America

Conventional El Niño forecasting techniques rely on dynamical and statistical climate models that analyze observations of sea surface temperatures (SSTs) and wind patterns. Although this forecast method can be quite accurate when making predictions a few months out, its skill is rather limited at longer-range forecasting. Accurate long-range forecasting is critical, however, to preparing for and mitigating the economic effects of El Niño events. For example, in the agricultural sector, farmers need to be able to plan which crops to plant based on expected weather conditions (e.g. hotter than normal, wetter than normal, drier than normal, etc) to reduce the likelihood of crop failure.

The study published by Ludescher, et al. this month claims to have developed a forecasting technique that can accurately predict ENSO fluctuations up to a year in advance by relying solely on statistical correlations between air temperatures across the Pacific region and upcoming changes to equatorial Pacific SSTs (i.e. upcoming El Niño or La Niña events). Although the study’s authors tout its long-range predictive ability, it cannot currently predict the magnitude (severity) of those upcoming events.

The study’s authors say that their technique accurately predicted the absence of El Niño during 2012 and 2013, but because the forecasting methodology is so new, it has yet to be tested in a prediction of non-neutral ENSO conditions. Many atmospheric scientists not involved with the study remain skeptical of the skill of the new technique for that reason as well as for the fact that the study does not propose an explanation as to why the statistical correlation should work. In other words, the study does not advance scientists’ understanding of the physical mechanisms that drive the ENSO cycle.

If the new statistical forecasting technique proves successful, though, it may alleviate a problem that has been plaguing conventional ENSO forecasters for the last couple of years and that may now be negatively affecting the skill of seasonal climate (e.g. ENSO) forecasts.

The National Oceanic and Atmospheric Administration (NOAA) maintains a network of moored buoys in the tropical Pacific Ocean to monitor real-time ocean temperatures for input into the climate models used to forecast El Niño and La Niña. Since budget cuts in 2012 forced NOAA to reduce its maintenance schedule of the buoys, however, over half of them have failed. With less detail about ocean temperatures in this critical location being provided by the thinning buoy network, forecast models may suffer a loss of accuracy.

Only time will tell. The dynamical and statistical climate models used to provide conventional ENSO forecasts are also beginning to predict an increased likelihood of El Niño conditions beginning in late 2014. It’s still too early for significant confidence, but those readers who are involved in weather-sensitive industries should monitor the situation closely and consider planning early for possible El Niño conditions beginning in late fall 2014.

Weather, Climate, and Atlanta Gridlock

We at Blue Skies Meteorological Services were fortunate to escape (by a margin of about 50 miles) the late-January winter storm that crippled much of the southeastern US last week. That storm, which brought one to three inches of snow to areas that rarely receive even a trace of frozen precipitation, clearly demonstrated the danger and damage that can occur when weather does not agree with climate norms.

A common, if somewhat over-simplified, explanation of the difference between weather and climate is:
Climate is what you expect;
Weather is what you get.

The day-long traffic gridlock in Atlanta, GA, on Jan 28th epitomizes the hazards of getting climatologically unexpected weather (and of failing to incorporate updated forecast information into emergency management decisions, but that’s outside the scope of this article). The magnitude of the weather event itself is relatively unimportant (as several colleagues from the Upper Midwest have noted, “Two inches of snow is just a normal Monday commute back home”). What matters in terms of societal impacts is the deviation of the event from normal, expected values. And the reason for this is simple – we prepare for what we expect.

As a student at Purdue University, receiving a couple inches of snow was an almost weekly winter occurrence. Snow in northern Indiana is a climate norm, so everyone is generally well prepared for it. Life proceeds without interruption thanks to stockpiles of salt/sand, fleets of snowplows, and battalions of snow plow drivers.

It’s a different story in the South, though, where 50 degrees is deemed parka weather, and where ice is typically found in tidy cubes in your sweet tea, not in impenetrable sheets coating your car windshield.  Frozen precip is an anomaly, and as such, residents and municipalities don’t maintain the infrastructure nor have the experience to deal with it as “business as usual”.

However, what is lacking in infrastructure can be addressed through effective planning. By understanding the range of extreme weather events and their climatological recurrence intervals, businesses and municipalities can develop and implement emergency plans that mitigate the damage and disruption that inevitably accompanies extreme weather events.

Two inches of snowfall will always be a big deal in Atlanta (and normal January weather in the Midwest), just like temperatures above 100 degrees will always be a big deal in Maine (and a standard late July afternoon in Oklahoma). When planning for and understanding the impacts of extreme weather in any location, we must remember that it’s not the absolute magnitude of the event that matters – it’s the deviation from the norm. It’s the difference between what you expect and what you actually get.

Note: Blue Skies Meteorological Services provides climate analyses, including of extreme weather recurrence intervals, in support of business and municipal emergency planning and hazard mitigation.