Less extreme and earlier outbursts of ice-dammed lakes since 1900.

Episodic failures of ice-dammed lakes have produced some of the largest floods in history, with disastrous consequences for communities in high mountains1-7. Yet, estimating changes in the activity of ice-dam failures through time remains controversial because of inconsistent regional flood databases. Here, by collating 1,569 ice-dam failures in six major mountain regions, we systematically assess trends in peak discharge, volume, annual timing and source elevation between 1900 and 2021. We show that extreme peak flows and volumes (10 per cent highest) have declined by about an order of magnitude over this period in five of the six regions, whereas median flood discharges have fallen less or have remained unchanged. Ice-dam floods worldwide today originate at higher elevations and happen about six weeks earlier in the year than in 1900. Individual ice-dammed lakes with repeated outbursts show similar negative trends in magnitude and earlier occurrence, although with only moderate correlation to glacier thinning8. We anticipate that ice dams will continue to fail in the near future, even as glaciers thin and recede. Yet widespread deglaciation, projected for nearly all regions by the end of the twenty-first century9, may bring most outburst activity to a halt.

Changing climate both increases and decreases European river floods.

Climate change has led to concerns about increasing river floods resulting from the greater water-holding capacity of a warmer atmosphere1. These concerns are reinforced by evidence of increasing economic losses associated with flooding in many parts of the world, including Europe2. Any changes in river floods would have lasting implications for the design of flood protection measures and flood risk zoning. However, existing studies have been unable to identify a consistent continental-scale climatic-change signal in flood discharge observations in Europe3, because of the limited spatial coverage and number of hydrometric stations. Here we demonstrate clear regional patterns of both increases and decreases in observed river flood discharges in the past five decades in Europe, which are manifestations of a changing climate. Our results-arising from the most complete database of European flooding so far-suggest that: increasing autumn and winter rainfall has resulted in increasing floods in northwestern Europe; decreasing precipitation and increasing evaporation have led to decreasing floods in medium and large catchments in southern Europe; and decreasing snow cover and snowmelt, resulting from warmer temperatures, have led to decreasing floods in eastern Europe. Regional flood discharge trends in Europe range from an increase of about 11 per cent per decade to a decrease of 23 per cent. Notwithstanding the spatial and temporal heterogeneity of the observational record, the flood changes identified here are broadly consistent with climate model projections for the next century4,5, suggesting that climate-driven changes are already happening and supporting calls for the consideration of climate change in flood risk management.

Historic Yangtze flooding of 2020 tied to extreme Indian Ocean conditions.

Heavy monsoon rainfall ravaged a large swath of East Asia in summer 2020. Severe flooding of the Yangtze River displaced millions of residents in the midst of a historic public health crisis. This extreme rainy season was not anticipated from El Niño conditions. Using observations and model experiments, we show that the record strong Indian Ocean Dipole event in 2019 is an important contributor to the extreme Yangtze flooding of 2020. This Indian Ocean mode and a weak El Niño in the Pacific excite downwelling oceanic Rossby waves that propagate slowly westward south of the equator. At a mooring in the Southwest Indian Ocean, the thermocline deepens by a record 70 m in late 2019. The deepened thermocline helps sustain the Indian Ocean warming through the 2020 summer. The Indian Ocean warming forces an anomalous anticyclone in the lower troposphere over the Indo-Northwest Pacific region and intensifies the upper-level westerly jet over East Asia, leading to heavy summer rainfall in the Yangtze Basin. These coupled ocean-atmosphere processes beyond the equatorial Pacific provide predictability. Indeed, dynamic models initialized with observed ocean state predicted the heavy summer rainfall in the Yangtze Basin as early as April 2020.

Fecal stanols show simultaneous flooding and seasonal precipitation change correlate with Cahokia's population decline.

A number of competing hypotheses, including hydroclimatic variations, environmental degradation and disturbance, and sociopolitical disintegration, have emerged to explain the dissolution of Cahokia, the largest prehistoric population center in the United States. Because it is likely that Cahokia's decline was precipitated by multiple factors, some environmental and some societal, a robust understanding of this phenomenon will require multiple lines of evidence along with a refined chronology. Here, we use fecal stanol data from Horseshoe Lake, Illinois, as a population proxy for Cahokia and the broader Horseshoe Lake watershed. We directly compare the fecal stanol data with oxygen stable-isotope and paleoenvironmental data from the same sediment cores to evaluate the role of flooding, drought, and environmental degradation in Cahokia's demographic decline and sociopolitical reorganization. We find that Mississippi River flooding and warm season droughts detrimental to agriculture occurred circa (ca.) 1150 CE and possibly generated significant stress for Cahokia's inhabitants. Our findings implicate climate change during the Medieval Climatic Anomaly to Little Ice Age transition as an important component of population and sociopolitical transformations at Cahokia, and demonstrate how climate transitions can simultaneously influence multiple environmental processes to produce significant challenges to society.

Public Health Emergency Response Lessons Learned by Rapid Deployment Force 3, 2006-2016.

Following Hurricane Katrina, the uniformed US Public Health Service created an updated system through which its officers participated in emergency responses. The Rapid Deployment Force (RDF) concept, begun in 2006, involved five teams of officers with diverse clinical and public health skill sets organized into an incident command system led by a team commander. Each team can deploy within 12 hours, according to a defined but flexible schedule. The core RDF mission is to set up and provide care for up to 250 patients, primarily persons with chronic diseases or disabilities, in a temporary federal medical station. Between 2006 and 2016, the RDF 3 team deployed multiple times in response to natural disasters and public health emergencies. Notable responses included Hurricane Sandy in 2012, the unaccompanied children mission in 2014, and the Louisiana floods in 2016. Lessons learned from the RDF 3 experience include the need for both clinical and public health capacity, the value of having special mental health resources, the benefits of collaboration with other federal medical responders, and recognition of the large burden of chronic disease management issues following natural disasters.

Leibniz's Observations on Hydrology: An Unpublished Letter on the Great Lombardy Flood of 1705.

Although the historical reputation of Gottfried Wilhelm Leibniz (1646-1716) largely rests on his philosophical and mathematical work, it is widely known that he made important contributions to many of the emerging but still inchoate branches of natural science of his day. Among the many scientific papers Leibniz published during his lifetime are ones on the nascent science we now know as hydrology. While Leibniz's other scientific work has become of increasing interest to scholars in recent years, his thinking about hydrology has been neglected, despite being relatively broad in extent, including as it does papers on the 'raising of vapours' and the formation of ice, as well as the separation of salt and fresh water. That list can now be extended still further following the discovery of a previously unpublished letter of Leibniz's on the causes of the devastating Lombardy flood of October and November 1705. This letter, which will be the focus of our paper, reveals the depth of Leibniz's understanding of key hydrological processes. In it, he considers various mechanisms for the flood, such as heavy rains on high ground, underwater earthquakes, and a mountain collapse. Over the course of the paper we examine each of these mechanisms in depth, and show that Leibniz was in the vanguard of hydrological thinking. We also show that the letter contains one of the first scholarly attempts to apply aspects of the still-forming notion of the hydrological cycle to account for a flood event.

Flooding and the framing of risk in British broadsheets, 1985-2010.

Our analysis of 2707 news stories explores the framing of flooding in Britain over the past quarter century and the displacement of a once dominant understanding of flooding as an agricultural problem of land drainage by the contemporary concern for its urban impacts, particularly to homes and property. We document dramatic changes in the volume and variety of reporting about flooding since 2000 as the risks of flooding have become more salient, the informal 'Gentlemen's Agreement' between government and private insurers has broken down, and flood management subjected to greater public scrutiny. While the historic reliance on private insurance remains largely unchallenged, we show that other aspects of flood hazard management are now topics of active political debate to which the looming threat of climate change adds both urgency and exculpatory excuses for poor performance. We conclude by reflecting on the significance of the case for grand theories of neoliberalisation and governmentality.

Long-term effects of flooding on mortality in England and Wales, 1994-2005: controlled interrupted time-series analysis.

BACKGROUND: Limited evidence suggests that being flooded may increase mortality and morbidity among affected householders not just at the time of the flood but for months afterwards. The objective of this study is to explore the methods for quantifying such long-term health effects of flooding by analysis of routine mortality registrations in England and Wales. METHODS: Mortality data, geo-referenced by postcode of residence, were linked to a national database of flood events for 1994 to 2005. The ratio of mortality in the post-flood year to that in the pre-flood year within flooded postcodes was compared with that in non-flooded boundary areas (within 5 km of a flood). Further analyses compared the observed number of flood-area deaths in the year after flooding with the number expected from analysis of mortality trends stratified by region, age-group, sex, deprivation group and urban-rural status. RESULTS: Among the 319 recorded floods, there were 771 deaths in the year before flooding and 693 deaths in the year after (post-/pre-flood ratio of 0.90, 95% CI 0.82, 1.00). This ratio did not vary substantially by age, sex, population density or deprivation. A similar post-flood 'deficit' of deaths was suggested by the analyses based on observed/expected deaths. CONCLUSIONS: The observed post-flood 'deficit' of deaths is counter-intuitive and difficult to interpret because of the possible influence of population displacement caused by flooding. The bias that might arise from such displacement remains unquantified but has important implications for future studies that use place of residence as a marker of exposure.

Nutrient and sediment concentrations and corresponding loads during the historic June 2008 flooding in eastern Iowa.

A combination of above-normal precipitation during the winter and spring of 2007-2008 and extensive rainfall during June 2008 led to severe flooding in many parts of the midwestern United States. This resulted in transport of substantial amounts of nutrients and sediment from Iowa basins into the Mississippi River. Water samples were collected from 31 sites on six large Iowa tributaries to the Mississippi River to characterize water quality and to quantify nutrient and sediment loads during this extreme discharge event. Each sample was analyzed for total nitrogen, dissolved nitrate plus nitrite nitrogen, dissolved ammonia as nitrogen, total phosphorus, orthophosphate, and suspended sediment. Concentrations measured near peak flow in June 2008 were compared with the corresponding mean concentrations from June 1979 to 2007 using a paired t test. While there was no consistent pattern in concentrations between historical samples and those from the 2008 flood, increased flow during the flood resulted in near-peak June 2008 flood daily loads that were statistically greater (p < 0.05) than the median June 1979 to 2007 daily loads for all constituents. Estimates of loads for the 16-d period during the flood were calculated for four major tributaries and totaled 4.95 x 10(7) kg of nitrogen (N) and 2.9 x 10(6) kg of phosphorus (P) leaving Iowa, which accounted for about 22 and 46% of the total average annual nutrient yield, respectively. This study demonstrates the importance of large flood events to the total annual nutrient load in both small streams and large rivers.

Envisioning disaster in the 1910 Paris flood.

This article uncovers the visual narratives embedded within the photography of the 1910 Paris flood. Images offered Parisians multiple ways to understand and construe the significance of the flood and provided interpretive frameworks to decide the meaning of this event. Investigating three interlocking narratives of ruin, beauty, and fraternité, the article shows how photographs of Paris under water allowed residents to make sense of the destruction but also to imagine the city's reconstruction. The article concludes with a discussion of the role of visual culture in recovering from urban disasters.

Fiji's worst natural disaster: the 1931 hurricane and flood.

At least 225 people in the Fiji Islands died as a result of the 1931 hurricane and flood, representing the largest loss of life from a natural disaster in Fiji's recent history. This paper explores the causes of disaster and the potential for recurrence. The disaster occurred because a rare event surprised hundreds of people-especially recently settled Indian farmers-occupying highly exposed floodplains in north-west Viti Levu island. The likelihood of a flood disaster of such proportions occurring today has been diminished by changed settlement patterns and building materials; however, a trend towards re-occupancy of floodplains, sometimes in fragile dwellings, is exposing new generations to flood risks. The contribution of this paper to the global hazards literature is set out in three sections: the ethnicity, gender and age of flood fatalities; the naturalness of disasters; and the merit of choice and constraint as explanations for patterns of vulnerability.

On the extraordinary winter flood episode over the North Atlantic Basin in 1936.

In this study, we analyze the linkage between atmosphere and ocean modes and winter flood variability over the 20th century based on long-term flow-discharge series, historical archives, and tree-ring records of past floods in the North Atlantic Basin (NAB). The most extreme winter floods occurred in 1936 and had strong impacts on either side of the Atlantic. We hypothesize that the joint effects of sea surface temperatures (SSTs) over the Atlantic and Pacific Oceans and the Arctic Oscillation (AO), which is closely related to the North Atlantic Oscillation, play a significant role when describing flood variability in North America and Europe since 1900. Statistical modeling supports the assumption that the response of flood anomalies over the NAB to AO phases is subsidiary of SST phases. Besides, we shed light on the extraordinarily winter flood of 1936 that was characterized by very high SSTs over both the Atlantic and Pacific (>98th percentile) and very low, negative values of AO (<1st percentile). This outstanding winter flood episode was most likely characterized by stratospheric polar vortex anomalies, which can usually be linked to an increased probability of storms in western and southwestern Europe and increased snowfall events in eastern North America. By assessing the flood anomalies over the NAB as a coupled AO and SST function, one could further the understanding of such large-scale events and presumably improve anticipation of future extreme flood occurrences.

Nursing in the Midwestern Flood.

: Editor's note: From its first issue in 1900 through to the present day, AJN has unparalleled archives detailing nurses' work and lives over more than a century. These articles not only chronicle nursing's growth as a profession within the context of the events of the day, but they also reveal prevailing societal attitudes about women, health care, and human rights. Today's nursing school curricula rarely include nursing's history, but it's a history worth knowing. To this end, From the AJN Archives highlights articles selected to fit today's topics and times.This month's article appeared in the September 1943 issue, and reported on the spring flooding that had ravaged several midwestern states. Rebecca M. Pond of the Red Cross noted that during the floods, nurses worked in "hutments and barracks in [the] Army airport, unused factory buildings, college buildings, town and rural school houses, Boy Scout camps, abandoned CCC [Civilian Conservation Corps] camps, and an annex to a state hospital." The nursing care provided sounds like nursing in today's disaster shelters: providing health assessments, immunizations, and emergency care; maintaining isolation precautions where needed; monitoring prenatal women, infants, young children, and the elderly or ill; and supervising housekeeping and sanitation services.In recent years, the United States has experienced particularly severe flooding and other disasters precipitated by climate change. In this month's issue, Cara Cook and colleagues explore the many ways in which today's nurses can help to prevent (and not only ameliorate) the effects of a changing climate.

How long do floods throughout the millennium remain in the collective memory?

Is there some kind of historical memory and folk wisdom that ensures that a community remembers about very extreme phenomena, such as catastrophic floods, and learns to establish new settlements in safer locations? We tested a unique set of empirical data on 1293 settlements founded in the course of nine centuries, during which time seven extreme floods occurred. For a period of one generation after each flood, new settlements appeared in safer places. However, respect for floods waned in the second generation and new settlements were established closer to the river. We conclude that flood memory depends on living witnesses, and fades away already within two generations. Historical memory is not sufficient to protect human settlements from the consequences of rare catastrophic floods.