WeatherZine WeatherZine Number 9, April 1998
"What's happening on the Societal Aspects of Weather WWW Site."


EditorialEl Niño and Armageddon

Community NewsA National Flood Loss Model

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El Niño and Armageddon

According to recent news reports, the documented damages to society related to the recent El Niño winter have been no worse than the previous two winters (non-El Niño). What are we to make of this?

A few weeks ago the U.S. Federal Emergency Management Agency (FEMA) released information showing that from November 1, 1997 to March 31, 1998 the agency had committed about $290 million in response to presidentially declared disasters. This amount is about the same as FEMA committed in each of the two previous winters. This statistic seems to have surprised FEMA, with one agency spokesperson commenting that "everybody was screaming that El Niño was going to be Armageddon, but our data reveals that's not what it's turned out to be."

Keeping Mark Twain's cautionary advice on statistics in mind, here are three suggestions about how you might interpret the FEMA data:

  1. El Niño impacts in the United States overall do not mean Armageddon

    What El Niño means is that different parts of the country are more or less likely to suffer particular weather events than in La Niña or neutral years. In fact, simply because hurricane damages are much larger during La Niña events, it is probably the case that the nation as a whole experiences LESS overall impacts in El Niño years than in many La Niña years. But for those places with strongly correlated weather impacts during El Niño events (like California), El Niño events might seem like Armageddon. In aggregate, however, El Niño is better thought of as a shift in the sort of weather impacts that we see, rather than as an overall increase for everyone.

  2. Predictions of El Niño-related impacts can reduce disaster costs

    The very fact that El Niño shifts the sort of impacts that the nation sees from non-El Niño years should provide usable information for those who are potentially affected. The summer and fall of 1997 saw a number of policy responses to scientific and media pronouncements that the Pacific Ocean was warming at an unprecedented rate. For instance, FEMA organized an El Niño summit in California to focus attention on the possibility of strong coastal storms. The state of Florida also organized an El Niño summit to focus attention on the possibility of extreme weather associated with thunderstorms. In both instances, the advance preparation proved prescient, as both states experienced extreme weather. These examples (and there are many others) provide a better picture of what El Niño information means to the nation than is provided by looking at aggregate impacts.

  3. Disaster costs alone do not provide a measure of the value of advance preparation

    One might be tempted to conclude that advance preparation efforts had little value because the past winter's disaster losses (according to FEMA) were similar to the previous two winters. This would be a mistake. Because weather impacts are highly random and FEMA's tabulation represents only a subset of documented impacts, one cannot compare different years and expect to see indication of the value of preparation. Consider that some in the insurance industry have speculated that better preparation for Hurricane Andrew might have saved $5 billion. But Andrew would have still been the costliest storm ever (in inflation-adjusted dollars only). Assessing the value of preparation, including advance warnings and forecasts, requires careful attention to the details of specific cases. This demands a considerable investment of time and attention. But if advance preparation is ever going to become a larger element of the nation's response to extreme weather, then we must know its costs and benefits.

The FEMA announcement suggests that perhaps the scientific community was at once too successful and not successful enough in publicizing last year's coming El Niño. They were too successful to the extent that people came to associate El Niño with Armageddon, and not successful enough to the extent that the public failed to appreciate the subtleties of extreme weather related to El Niño. These are important lessons to learn as the nation develops skill in interannual forecasting.

— Roger A. Pielke, Jr.

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Community News

A National Flood Loss Model

In the past, escalating flood damages have become a significant concern of citizens, floodplain managers, and policy makers. In particular, practitioners and policy makers are seeking out new ways to reduce flood damages and make wise use of the nation's floodplains. Reducing disaster payments and payouts from the National Flood Insurance fund are also key objectives. To meet these goals, it was realized that tools for estimation flood losses are needed to be put into the hands of the practitioners who most directly impact the decision making process in local communities concerning land use policies, code enforcement, emergency preparedness, and other flood control strategies.

The HAZUS (Hazards US) Model utilizes GIS technologies with hazard identification, and loss estimation tools. The first HAZUS model addressed earthquake loss estimation and has become an essential element in FEMA's Project Impact. FEMA is now beginning to expand the HAZUS model to perform similar loss evaluations for other hazards, including flood, hurricane, tornado, coastal storm surge, and severe winter storms and thunderstorms. The current modeling effort will expand HAZUS to allow practitioners to plan for, and evaluate the potential effects of mitigation planning activities on flooding and flood loss.

NIBS and FEMA have initiated the development of a flood module for HAZUS (the "flood model"). The purpose of the flood model is to provide a nationally applicable standardized methodology for estimating potential flood losses on a regional basis. The model will be used to estimate potential flood effects and to assist in developing mitigation planning strategies. It will also enable those involved in emergency response and recovery to be better prepared for future flood events.

For more info see the FEMA and NIBS websites.

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New Additions to the WWW Site

Emergency Management

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Extreme Temperatures

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Tropical Cyclone

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El Niño

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Insurance Industry

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Economic & Casualty Data

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Last issue we failed to acknowledge UCAR's role in the development of an AMS Congressional Fellows program. The news item has been corrected.

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