Category Archives: Natural Catastrophe Risk

Disaster Risk Reduction: Avoiding the Inevitable

While natural hazards are inevitable, their impact on any given community is not. This is the thrust of the #NoNaturalDisasters campaign.

There’s a truth behind the hashtag. Modern societies are increasingly capable of determining their resilience to natural hazards. We nowadays know enough to prevent extreme weather events from escalating into full-blown disasters. In developed nations, sophisticated forecasting systems, social media networks and engineering capabilities can make any weather-related death seem like pure bad luck.

So, if it’s all down to chance, no particular group in society should be at higher risk. The truth, however, is rather different.

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Cricket Balls from the Sky: Twenty-Year Retrospective on the 1999 Sydney Hailstorm

Still ranked within the top three largest insured loss events in Australia’s history, it has now been twenty years since a hailstorm shattered roofs across the eastern suburbs of Sydney on April 14, 1999. And recent events continue to show the significant risk posed by severe hailstorms – on December 20, 2018, Sydney was hit by “…the worst hailstorm in twenty years” according to the Australia Bureau of Meteorology. On the anniversary of the 1999 storm, we look at both these events and discuss the return period of significant hail losses in Sydney.

For the 1999 event, the large hail associated with the storm damaged 24,000 homes and 70,000 automobiles along its path. There has been much written about the 1999 event, and in 2009 RMS published a detailed 10-year retrospective, but in short, this storm was unusual for several reasons:

  • April 14 was outside of the normal storm season which tends to focus around September through to March
  • The storm had hit late in the day, at 8 p.m. local time; most hit during the mid to late afternoon
  • The size of the hailstones was very large, described at the time as “… cricket-ball, melon, or grapefruit sized…” and up to 12 centimeters (4.7 inches) wide.

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The All-Peril Cat Five

Why the Saffir-Simpson Hurricane Intensity Scale had five levels we don’t know. The digits on a hand? Better than three, but lower resolution than the dozen rungs for wind speeds or earthquake intensity? Whatever the reason it seems to work.

In the late 1960s, Herbert Saffir, a Florida building engineer, was sent by the United Nations to study the hurricane vulnerability of low-cost housing in the Caribbean. He realized something was needed to rank hurricane destructiveness. Saffir had some “Richter envy” from observing the ease with which seismologists now communicated with the public. In 1971, he contacted Robert Simpson, head of the National Hurricane Center to help link damage levels with wind speeds.

Seeing the opportunity to communicate evacuation warnings, Simpson also added details around the height of advancing storm surges. Better information was clearly needed, after the loss of life in Hurricane Camille on the Mississippi coast in 1969.

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European Floods and the Relationship with the North Atlantic Oscillation

Stefano Zanardo, Principal Modeler, RMS

Ludovico Nicotina, Senior Director – Modeling, RMS

Arno Hilberts, Vice President, Model Development, RMS

Steve Jewson, Scientific Research Consultant, RMS

The North Atlantic Oscillation (NAO) describes the fluctuations in the difference of atmospheric pressure at sea level between two semi-permanent centers of low and high pressure in the North Atlantic: the Icelandic Low and the Azores High. Fluctuations between these centers control the strength and direction of westerly winds and location of storm tracks across the North Atlantic.

Why is this important? The NAO signal is Europe’s dominant mode of climate variability and correlates highly with European precipitation patterns. Typically, when the NAO is positive – characterized by a higher than average pressure difference between low and high latitudes of the Northern Hemisphere, Northern Europe experiences strong westerly winds. This causes stormier and wetter than usual conditions in Northern Europe, while Southern Europe is drier and colder than usual.

In contrast, when the NAO is negative, Southern Europe experiences westerly winds and the meteorological pattern is somewhat opposite, with Southern Europe being generally wetter than average. The NAO is significantly stronger in winter than in the other seasons, therefore, most studies on the NAO focus on winter months, when the influence of the NAO on surface temperature and precipitation is highest.

When climate patterns result in changing prevailing conditions, such as increased storm activity and rainfall, it is important to understand their effect in relation to the severity of flood events – responsible for significant property damage, business disruption and loss of life in Europe. And there is a need to understand its ongoing impact as the climate and the distribution of exposures change over time.

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Exceedance 2019: Expanding Your Horizons

Regular attendees to the annual RMS Exceedance conference will know how comprehensive our agenda is, in terms of the sheer breadth of topics and areas we cover. Our aim is to deliver a program designed to highlight the issues, opportunities, and the solutions available to tackle the challenges that the risk management industry faces.

Join us in Miami (May 13 – 16) for this year’s Exceedance, and in addition to our keynote presentations (and of course, social events, The Expert Bar, our thirtieth anniversary, and the EP), the mainstay of our conference focuses on sessions spanning across seven in-depth “track” themes.

Our tracks cover a broad range within its defined theme over two days, with educational sessions, panel discussions, case studies, and “how-to” and technical deep-dives. All the track descriptors are available on the Exceedance website. Attendees can immerse themselves in a single track or pick and mix across all seven to create their perfect agenda.

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The Age of Innocence

Professor Ilan Noy holds a unique ”Chair in the Economics of Disasters” at the Victoria University of Wellington, New Zealand. He has proposed in a couple of research papers that instead of counting disaster deaths and economic costs, we should report the “expected life-years” lost, not only for human casualties but also for the life-years of work that will be required to repair all the damage to buildings and infrastructure.

The idea is based on the World Health Organization’s Disability Adjusted Life Years (DALYs) lost through disease and injury (WHO 2013). The motivation is to escape from the distortion introduced by measuring the impact of global disasters in dollars, as loss from the richest countries will always dominate this metric. Noy’s proposal converts injuries into life-years lost, based on how long it takes for the injured to return to complete health, while also factoring the degree of permanent disability multiplied by its duration. This is topped up by a “welfare reduction weight” for all those exposed to a disaster. The final component of the index attempts to capture how many years of human endeavor is lost to recovering the buildings and assets destroyed in the disaster.

There is plenty to argue over in terms of how deaths, injury and damage should be combined. In particular, the assumption that additional work to rebuild a city, is the same as a shortened life, seems somewhat reductive.

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Cutting Out Wildfire Risk from the California Electricity Grid

On January 30, Judge William Alsup, district judge for the Northern District of California presided over a hearing to discuss the inclusion of wildfire prevention in a 2016 Probation Order mandated to Pacific Gas and Electric (PG&E) in the aftermath of the 2010 San Bruno gas explosion that left eight dead.

An order to add conditions to their existing probation, filed on January 9, aimed to “…protect the public from further wrongs by the offender, to deter similar wrongs by other utilities, and to promote the rehabilitation of the offender…” The order included the determination from CAL FIRE that PG&E caused 18 wildfires in 2017, with CAL FIRE continuing its investigations into the causes of the more recent Camp Fire last year.

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Meet the Trekkers

This year’s RMS Impact Trek, to help support the work of our longstanding partner, Build Change, heads off to the Philippines on March 17. A team of RMS employees and RMS clients will work together on a 10-day trek with Build Change to learn more about how to ensure communities benefit from safe housing, through the use of retrofitting and sound construction methods. The skills that both our employees and clients bring are very complementary to these tasks, and knowledge of risk modeling and analytics, and how to apply this knowledge to develop resilience is highly valued. For more insight, watch the video below from the 2018 Impact Trek in Nepal.

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International Women’s Day: A Call to Action

March 8 is International Women’s Day (IWD). It’s a day to celebrate the achievements of women and to highlight the ongoing struggle in achieving equal rights for women across the globe.

The theme of the United Nations’ observance of #IWD2019 is particularly resonant at RMS: “Think Equal, Build Smart, Innovate for Change.” Given the discriminatory impact from catastrophes, where the vulnerable in society suffer the most, this theme is especially relevant to our mission to increase resilience to disasters.

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Northern California: Fire and Water

From major wildfires just over four months ago, and now major flooding, Northern California seems to leap from one perilous state to another. This time, rainfall from a “potent atmospheric river”, as described by the National Weather Service, caused flooding to over 3,000 properties in Sonoma County. This atmospheric river – a flowing column of condensed water vapor pumped up from the Tropics which can be up to 375 miles (603 kilometers) wide – started delivering rain and snow into the region late on Sunday, February 24.

The small town of Guerneville (pop. ~4,500) fared worst, reporting nearly 21 inches (529 millimeters) of rainfall in just 72 hours by 5 p.m. local time on Wednesday, February 27. The source of the town’s flooding was the Russian River, which flows from Mendocino County through to Sonoma County, reaching a maximum level of 45.5 feet (13.9 meters) at Johnson’s Beach, near Guerneville. This exceeded the defined 40 feet (12.1 meters) threshold for a major flood at this point, with local media reports stating that this is the worst flooding since New Year’s Day in 1997, when the river rose to 45 feet (13.7 meters). The nearby Napa River also crested at 26 feet (7.92 meters), one foot above the flood stage.

The town of Guerneville, which was originally built on a meander in the river, on February 27 was declared by the Sonoma County Sheriff’s Office “… [as] officially an island …” as all roads in an out of the town were flooded. 4,000 residents in both Guerneville and Monte Rio (pop. ~1,200) were under evacuation orders until Friday, March 1.

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