The Major Snow Avalanche Cycle of February 1986 in the Western United States

Snow avalanches are a significant hazard in mountainous environments around the world. This paper investigates the major February 1986 avalanche cycle that occurred in the western United States, and broadly analyzes the avalanche, snowpack, and weather conditions at twenty sites. These analyses suggest that the avalanche cycle resulted from the interaction of a relatively `normal' snowpack with an exceptional storm event, which was particularly noteworthy for the amount of precipitation it produced. Composited 500-hPa anomaly maps show the event resulted from an uncommonly persistent blocking pattern that resulted in a strong zonal flow and copious moisture being funneled over the western United States. Understanding severe and widespread avalanche cycles may improve our long-term forecasting of these events, and help mitigate theresulting avalanche activity.     

Occurrence of emergencies and disaster analysis according to precipitation amount

An analysis of the occurrences of events related to precipitation, considering extensive and intensive risk, i.e., emergencies and disasters, based on twenty-nine years of data for five cities of Ecuador provided relevant information about the behavior over time of floods, river overflows and landslides. The records of events were examined in the immediate and in the short term, which corresponded to 5 and 30 days, respectively, using the data mining methods k-means and association rules, to identify the patterns that govern their behaviors with respect to the observed amount of precipitation. The results show an increase in the frequency of similar events, with the occurrences being separated by shorter periods in recent decades. The behavior of emergencies and disasters indicates that emergencies are expected for periods of 5 days, with low quantities of precipitation and for periods of 30 days with normal quantities of precipitation. Disasters are expected, for both periods of 5 and 30 days, in the higher quantiles of precipitation. Interrelations between floods, river overflows and landslides were identified in all cities, with at least one relationship between two of the hazards for each city. An apparent flood–river overflow–landslide cycle could explain the mechanics of their occurrence. The information provided by the results indicates the vulnerability of the cities over time, their low capacity to support normal quantities of precipitation and their high exposure to hydro-meteorological hazards. The products obtained could be used together with precipitation prediction to anticipate possible effects and to formulate adequate risk management policies.     

Severe weather affecting European transport systems: the identification,classification and frequencies of events

Severe weather can have serious repercussions in the transport sector as a whole by increasing the number of accidents, injuries and other damage, as well as leading to highly increased travel times. This study, a component of the EU FP7 Project EWENT, delineates a Europe-wide climatology of adverse and extreme weather events that can be expected to affect the transport network. We first define and classify the relevant severe weather events by investigating the effects of hazardous conditions on different transportation modes and the infrastructure. Consideration is given to individual phenomena such as snowfall, heavy precipitation, heat waves, cold spells, wind gusts; a combined phenomenon, the blizzard, is also considered. The frequency of severe weather events, together with the changes in their spatial extension and intensity, is analyzed based on the E-OBS dataset (1971–2000) and the ERA-Interim reanalysis dataset (1989–2010). Northern Europe and the Alpine region are the areas most impacted by winter extremes, such as snowfall, cold spells and winter storms, the frequency of heavy snowfall. The frequency of hot days is highest in Southern Europe. Severe winds and blizzards are the most common over the Atlantic and along its shores. Although heavy rainfall may affect the whole continent on an annual basis, extreme precipitation events are relative sparse, affecting particularly the Alps and the Atlantic coastline. A European regionalization covering similar impacts on the transport network is performed.     

Freezing rain events: a major weather hazard in the conterminous US

Freezing rain (FZRA) is well documented as a major weather hazard, producing damage to structures, the environment, and humans, and delaying various operations such as transportation. Assessing the risk of freezing rain events requires information for various areas of the nation about the frequency, duration, and intensity of these events along with the associated weather conditions that affect the damage caused by freezing rain. This includes temperatures (dry and wet bulb), the amount of precipitation, and winds during freezing rain. The purpose of this work was to develop a national and regional climatology of freezing rain events in the US for the period of 1928–2001 to addresses these conditions.     

Characteristics of the top ten snowstorms at First-Order Stations in the U.S.

Snowstorms can produce varying degrees of damage depending on the amount and intensity of the snowfall over a given amount of time. Concurrent weather conditions such as freezing rain and high winds often exacerbate the amount of damage received. In order to assess the frequency of potentially damaging conditions during climatologically significant snowstorms, the top ten snowstorms (TTS) at individual First-Order Stations in the eastern two-thirds of the conterminous U.S. were determined, and the hourly weather conditions during each event were analyzed. The results show that TTS have occurred as early as September and as late as June, with January being the peak month of occurrence. Hourly precipitation totals during TTS were 2.3 mm or less 88% of the time. Seven percent of TTS were classified as a blizzard with over half of the blizzards occurring in the West North Central region. The most common concurrent weather condition during a TTS was fog followed by blowing snow. Regionally, heavy snow events in the Northeast had relatively higher precipitation amounts, colder temperatures, higher winds, and more fog and blowing snow than any other region.     

The impact of extreme weather and climate change on inland waterway transport

Similarly to other modes of transport, inland waterway transport has to deal with weather events, affecting navigation conditions and the infrastructure on inland waterways. Most significant extreme weather events result from high precipitation, droughts and temperatures below zero degrees Celsius. Heavy rainfall, in particular in association with snow melt, may lead to floods resulting in suspension of navigation and causing damage to the inland waterway infrastructure as well as the property and health of human beings living in areas exposed to flooding. Long periods of drought may lead to reduced discharge and low water levels, limiting the cargo-carrying capacity of vessels and increasing the specific costs of transportation. Temperatures below zero degrees Celsius over a longer period may cause the appearance of ice on waterways, leading to suspension of navigation and possible damage to infrastructure, for example, buoys. Neither extreme weather events as well as climate change are new phenomena nor is their general occurrence expected to change suddenly. However, due to climate change, extreme weather events may change positively or adversely in severity and frequency of occurrence, depending on the respective weather event and the location of its occurrence. This paper gives an overview of the impact of extreme weather events on inland waterway transport in Europe, focussed on the Rhine–Main–Danube corridor, followed by a discussion on how climate change will change these events and their impacts.     

Characterization and assessment of the devastating natural hazards across the Canadian Prairie Provinces from 2009 to 2011

From 2009 to 2011, the Canadian Prairies were subjected to exceptionally variable precipitation regimes, ranging between record drought and unprecedented flooding. Adjacent regions concurrently experienced droughts and floods, and individual areas transitioned rapidly from pluvial to drought conditions and vice versa. Such events had major impacts; for example, damages from floods in the Assiniboine River Basin (ARB) have exceeded $1 billion, and forest fires ravaged the town of Slave Lake, Alberta. This study first characterizes, and then assesses, these devastating natural hazards in terms of their physical processes (across multiple spatial and temporal scales) related to both the spatially contrasting precipitation states and rapid temporal transitions between these states. Subtle differences in large-scale atmospheric flow had marked impacts on precipitation. Primary factors controlling the distribution and amount of precipitation included the location and persistence of key surface and upper-air features, as well as their interaction. Additionally, multiple events—rather than individual extremes—were responsible for the flooding over the Saskatchewan River Basin and the ARB. Very heavy rainfall events (≥25 mm d^?1) accounted for up to 55 % of warm season rain at some locations, and the frequency of heavy rainfall events was critical for determining whether a region experienced drought or pluvial conditions. This study has increased our knowledge of the characteristics, impacts and mechanisms of rapidly transitioning disparate precipitation states on the Canadian Prairies and will aid in better understanding both past and projected future hydro-climatic extremes in the region.     

江苏省洪涝灾情及风险的时空分析

采用灰色关联分析,计算全省各市2011—2017年洪涝灾情指数;运用熵权法估算洪涝风险指标权重,评估各市2005—2018年综合洪涝风险.主要结果表明:选取的灾情指标能有效地反映区域洪涝灾情,扬州是全省历史灾情较为严重的城市,全省大部分城市在2012年和2015年的灾情指数较高,2016年苏南和苏中的灾情较严重;各市在...     

Quantifying weather conditions for rock fall hazard management

Relationships between weather conditions and rock fall occurrences have been acknowledged in the past, but seldom have such relationships been quantified and published. Rock falls are frequent hazards along transportation corridors through mountainous terrain, and predicting hazardous rock fall periods based on weather conditions can enhance mitigation approaches. We investigate the relationship between weather conditions and rock fall occurrences along a railway section through the Canadian Cordillera. Monthly weather-rock fall trends suggest that the seasonal variation in rock fall frequency is associated with cycles of freezing and thawing during the winter months. The intensity of precipitation and freeze–thaw cycles for different time-windows was then compared against recorded rock falls on a case-by-case approach. We found that periods when 90% of rock falls occurred could be predicted by the 3-day antecedent precipitation and freeze–thaw cycles. Some rock falls not predicted by this 3-day antecedent approach occurred during the first two weeks of spring thaw. These findings are used to propose a rock fall hazard chart, based on readily available weather data, to aid railway operators in their decision-making regarding safe operations.     

The spatial dynamics of atmospheric pollution in Latvia and the Baltic Republics,as measured in mosses,topsoil and precipitation

Atmospheric pollution in the Baltic countries of Estonia, Latvia, and Lithuania has been mapped using measurements of pollutant concentrations in mosses, topsoil and precipitation. Air masses from western Europe deposit industrial pollutants in the Baltic region and concentrations depend on meteorological conditions. Superimposed on this background is the pattern of deposits from local sources. Large areas receive neutral to basic precipitation due to cement industries and fly ash emissions from fossil fuel combustion. The burning of oil-shale in NE Estonia results in precipitation with pH values over 7.0, and high concentrations of V, Fe, and Cd. Heavy metal concentrations in the topsoil around large cities indicate ecologically unsound city planning and insufficient control of pollutants. The Chernobyl effect in the form of radioactive deposition depended on rainfall events during the accident.     

Ideological and volume politics behind cloud water resource governance – Weather modification in China

Weather modification operations are the intentional alteration of weather and cloud water conditions using technologies such as cloud seeding. Post-socialist authoritarian China is the world’s leading user of state power for rainfall enhancement through weather modification, with diverse purposes including agriculture production, water security, ecological preservation, and mega events. We argue that weather modification in China needs to be understood as a facet of ecological modernization, in which the authoritarian state believes that precipitation can be controlled through the use of advanced technologies, thus transforming clouds into a kind of cloud water resource. Two political dimensions are highlighted to understand precipitation control and utilization of cloud water: the first is a new ideological politics of the changing human-weather relationship from ‘adaptation to the weather’ to ‘taming the weather”; the second is volume politics that presents unique characteristics of airborne water as opposed to terrestrial and groundwater.     

Thunderstorm Hazard vulnerability for the Atlanta,Georgia metropolitan region

Most U.S. metropolitan regions have experienced urban “sprawl,” or the outward spreading of urban development from city centers. For cities lying in areas prone to severe weather, the sprawl phenomenon exposes greater numbers of developed areas and inhabitants to a variety of thunderstorm hazards. This study’s principal goal is to determine how urbanization growth patterns affect a region’s vulnerability to severe weather events. To assess how sprawl may impact vulnerability to tornadoes, hail, and convective wind events, an analysis examining potential loss may be utilized. This study employs two distinct approaches to examine how the Atlanta area’s rapid and extensive development during the latter half of the twentieth Century has affected its overall potential exposure to thunderstorm hazards. First, archived census data are used to estimate overall impacts from hypothetical significant tornado, nontornadic convective wind, and hail events occurring at different time periods throughout several locations in the Atlanta metropolitan region. Second, economic factors are integrated into the analysis, which assists in determining how these hypothetical severe event scenarios may have changed from a cost standpoint if they were to occur in 2006 as opposed to 1960.     

Copula-based evaluations of drought variations in Guangdong, South China

Changing characteristics of hazardous weather-related events have been arousing considerable public interest in recent years. Guangdong is an economically developed province in China and is prone to natural hazards. Using monthly precipitation data covering a period of 1956?C2008 from 127 rain gauge stations, the probabilistic behaviors of SPI-based droughts were investigated with copulas functions. Results indicated a higher risk of droughts along the coastal regions and the western Guangdong, particularly the Pearl River Delta (PRD) region. Joint probabilities of droughts with higher intensity and longer duration were found to have relatively even geographical distribution across Guangdong. The northern parts of Guangdong are higher in altitude and have a lower risk of droughts. Identification of regions characterized by droughts of different severity and durations across Guangdong is important for scientific management of water resource and agricultural activities and also the development of social resilience under the influence of climate changes.     

Comprehensive evaluation of urban flood-bearing risks based on combined compound fuzzy matter-element and entropy weight model

The extreme precipitation events caused by climate change and the rapid development of urbanization have brought hidden flood risks to the cities. This paper comprehensively considered two major factors of vulnerability of urban flood-bearing and disaster prevention and mitigation (DPAM) capacity and built a comprehensive evaluation index system for urban flood-bearing risks. Secondly, a combined model consisted of composite fuzzy matter-element and entropy weight model was constructed to calculate the comprehensive risk indicator. Finally, the Zhengzhou City was taken as an example, the comprehensive indices of urban flood-bearing risk from 2006 to 2015 were evaluated. The results showed that the comprehensive risk of Zhengzhou City was generally on a slow upward trend, from II level (moderate-risk) in 2006 to III level (secondary high-risk) in 2015, which was mainly due to the mismatch between the rapid development of urbanization and the slow improvement of DPAM capabilities. This paper is expected to provide scientific reference and technical support for urban flood disaster prevention and sponge city construction.

     

Regional frequency analysis of daily rainfall extremes using L-moments approach

Daily extreme precipitation values are among environmental events with the most disastrous consequences for human society. Information on the magnitudes and frequencies of extreme precipitations is essential for sustainable water resources management, planning for weather-related emergencies, and design of hydraulic structures. In the present study, regional frequency analysis of maximum daily rainfalls was investigated for Golestan province located in the northeastern Iran. This study aimed to find appropriate regional frequency distributions for maximum daily rainfalls and predict the return values of extreme rainfall events (design rainfall depths) for the future. L-moment regionalization procedures coupled with an index rainfall method were applied to maximum rainfall records of 47 stations across the study area. Due to complex geographic and hydro-climatological characteristics of the region, an important research issue focused on breaking down the large area into homogeneous and coherent sub-regions. The study area was divided into five homogeneous regions, based on the cluster analysis of site characteristics and tests for the regional homogeneity. The goodness-of-fit results indicated that the best fitting distribution is different for individual homogeneous regions. The difference may be a result of the distinctive climatic and geographic conditions. The estimated regional quantiles and their accuracy measures produced by Monte Carlo simulations demonstrate that the estimation uncertainty as measured by the RMSE values and 90% error bounds is relatively low when return periods are less than 100 years. But, for higher return periods, rainfall estimates should be treated with caution. More station years, either from longer records or more stations in the regions, would be required for rainfall estimates above T=100 years. It was found from the analyses that, the index rainfall (at-site average maximum rainfall) can be estimated reasonably well as a function of mean annual precipitation in Golestan province. Index rainfalls combined with the regional growth curves, can be used to estimate design rainfalls at ungauged sites. Overall, it was found that cluster analysis together with the L-moments based regional frequency analysis technique could be applied successfully in deriving design rainfall estimates for northeastern Iran. The approach utilized in this study and the findings are of great scientific and practical merit, particularly for the purpose of planning for weather-related emergencies and design of hydraulic engineering structures.     

Climate change and increased risk for the insurance sector: a global perspective and an assessment for the Netherlands

Climate change is projected to increase the frequency and severity of extreme weather events. As a consequence, economic losses caused by natural catastrophes could increase significantly. This will have considerable consequences for the insurance sector. On the one hand, increased risk from weather extremes requires assessing expected changes in damage and including adequate climate change projections in risk management. On the other hand, climate change can also bring new business opportunities for insurers. This paper gives an overview of the consequences of climate change for the insurance sector and discusses several strategies to cope with and adapt to increased risks. The particular focus is on the Dutch insurance sector, as the Netherlands is extremely vulnerable to climate change, especially with regard to extreme precipitation and flooding. Current risk sharing arrangements for weather risks are examined while potential new business opportunities, adaptation strategies, and public–private partnerships are identified.     

Stumbling upon history: collective memory and the urban landscape

Notable historical events are most commonly commemorated by state-sanctioned monumental structures designed as collective memorials. In contrast, this essay attends to Gunter Demnig’s Stumbling Stones, a countermemorial to the Holocaust, set in the vernacular landscape of cities throughout Europe. As participants in a trip sponsored by the German government, bringing American Jews to the capital city of Berlin, we reflect upon our experiences as we question the narrative differences between monumental memorials and countermemorials. This ethnographic study moves the reader through the crowded boulevards of Germany’s capital city, past historical sites and into museums where we share space and commune with the voices of the past that have come to define individual and collective memory in Berlin.     

吉林省重大暴雨过程灾害损失风险预评估

利用吉林省50县市1951-2013年逐日降水资料、暴雨灾情损失数据,1：5万DEM数据、水系、TM遥感卫星影像资料以及GDP、人口等数据,探讨了吉林省重大暴雨过程灾害损失风险的主要影响因素,确立了各因素的权重系数,构建了吉林省重大暴雨过程灾害损失风险评估模型.利用过程预报降雨量对2013年8月14-17日的重大暴雨过程灾害损失风险进行了预评估.结果表明：重大暴雨过程灾害损失综合风险的高值区分布在四平、辽源大部以及长春、吉林、通化城区附近,风险偏高区位于中南部,西部地区和东北部地区为中低风险区.灾害损失风险评估模型预评估效果良好,可在实际的暴雨过程灾害损失风险预评估业务中使用,由于通过该模型的评估结果可迅速圈定各级洪涝风险区,对提高重大暴雨过程应对能力、减少灾害损失以及防灾减灾意义重大.     

Firm finances, weather derivatives and geography

This paper considers some intellectual, practical and political dimensions of collaboration between human and physical geographers exploring how firms are using relatively new financial products - weather derivatives - to displace any costs of weather-related uncertainty and risk. The paper defines weather derivatives and indicates how they differ from weather insurance products before considering the geo-political, cultural and economic context for their creation. The paper concludes by reflecting on the challenges of research collaboration across the human-physical geography divide and suggests that while such initiatives may be undermined by a range of institutional and intellectual factors, conversations between physical and human geographers remain and are likely to become increasingly pertinent. The creation of a market in weather derivatives raises a host of urgent political and regulatory questions and the confluence of natural and social knowledges, co-existing within and through the geography academy, provides a constructive and creative basis from which to engage with this new market and wider discourses of uneven economic development and climate change.     

Corporate knowledge transfer via interlocking directorates: a network analysis approach

This paper explores spatial changes to knowledge transfer by Canadian and American corporate networks from 1976 to 1996. Results support facets of a World Cities approach for Canada. Toronto lies at the top of the hierarchy, while Montreal, Calgary, and Vancouver fall into a third tier of specialized regional cities. The American knowledge network also possesses facets of the world cities approach. The world city, New York, lies at the top of the hierarchy. Further down, Chicago is a specialized national city, while a number of regional centers have emerged to play a larger role over the twenty-year study period. A third tier of cities has emerged to play the critical role of specialized regional cities. This geographical phenomenon can be explained in terms of industry, headquarters locations, and network maturity. Finance, insurance and real estate, as well as “other manufacturing” are three sectors of the economy that are prominent in the network. In Canada, these sectors have increasingly centralized in Toronto while decentralizing in the United States. Similarly, the headquarters location of American firms is decentralizing from New York and Chicago, while Canadian headquarters continue to be centralized in Toronto. Finally, results indicate that the potential for knowledge transfer depends upon maturity of the system under investigation. The mature US network with a large pool of qualified business individuals is better suited for knowledge transfer at the regional level. The Canadian network is less developed and not appropriate for regional systems of knowledge transfer. The result is a Canadian corporate knowledge threshold that encompasses the entire country while a number of much smaller corporate knowledge thresholds appear across the United States.