Storm Damage Risk Research Articles

Conceptualization and First Realization Steps for a Multi-Camera System to Capture Tree Streamlining in Wind

Forests and trees provide a variety of essential ecosystem services. Maintaining them is becoming increasingly important, as global and regional climate change is already leading to major changes in the structure and composition of forests. To minimize the negative effects of storm damage risk, the tree and stand characteristics on which the storm damage risk depends must be known. Previous work in this field has consisted of tree-pulling tests and targets attached to selected branches. They fail, however, since the mass of such targets is very high compared to the mass of the branches, causing the targets to influence the tree’s response significantly, and because they cannot model dynamic wind loads. We, therefore, installed a multi-camera system consisting of nine cameras that are mounted on four masts surrounding a tree. With those cameras acquiring images at a rate of 10 Hz, we use photogrammetry and a semi-automatic feature-matching workflow to deduce a 3D model of the tree crown over time. Together with motion sensors mounted on the tree and tree-pulling tests, we intended to learn more about the wind-induced tree response of all dominant aerial tree parts, including the crown, under real wind conditions, as well as dampening processes in tree motion.

Under storm risk, economic productivity of Norway spruce (Picea abies (L.) H. Karst) in monoculture shows sharper decline than in mixture with European beech (Fagus sylvatica L.)

Key messageBy calibrating and validating a forest growth model for seven species in Germany and coupling it with a wind damage simulator, we specifically estimated the impact of wind damage on the net present value of Norway spruce and European beech in mixture and monoculture. Under risk, the net present value of spruce managements saw the sharpest declines, although the highest end net present value was still obtained through a heavily thinned spruce monoculture.ContextWind damage is one of the most important risks to Central European forests, and adaptation measures are essential.AimAdaptive management strategies should simultaneously account for forest production and wind risk. We simulated the effect of adaptive measures on wind-risk in German forests.MethodsA process-based forest growth model, “3-PG Mix”, was recalibrated and coupled with the storm damage risk model “Lothar”. We investigated the effect of thinning regimes on wind risk in monoculture and mixed species stands. The net present value of the simulated regimes was calculated and compared (risk vs. no risk).ResultsSpruce regimes achieved the highest net present values when risk was not considered. Considering risk in spruce and beech mixtures and monoculture, all regimes reached values below 3000 € ha−1 by year 120. The exception was a heavily thinned spruce monoculture at 4507 € ha−1, being the most profitable regime under risk.ConclusionWe conclude, on the basis of this modelling study, that heavy thinning reduced storm risk and maintained a higher net present value in spruce. Species mixture of beech and spruce saw net present values levels remain more constant under risk, while beech monoculture increased.

How Hurricane Katrina influenced the design of hurricane protection and risk reduction systems and national approaches to risk and resilience. Part 2: Designing the Hurricane and Storm Damage Risk Reduction System and resulting long-term engineering guidance and practice changes

Abstract Following Hurricane Katrina, the US Army Corps of Engineers, supported in part by the risk and reliability analysis conducted by the Interagency Performance Evaluation Task Force (IPET), made a major shift from ‘protection’ to ‘risk reduction’ as the principal goal in flood mitigation. The mitigation of the flood risk in Southeast Louisiana was embodied in the design and construction of the ‘Hurricane and Storm Damage Risk Reduction System’, the post-Katrina initiative for New Orleans flood mitigation. It also spawned a major overhaul of many of the Corps of Engineers’ technical guidance and engineering practice documents, incorporating risk as a key measure in the planning and design processes. The criteria applied for the design of the HSDRRS are discussed, with summaries of the associated major changes in Corps engineering guidance and practice relevant to flood mitigation.

Storm damage risk assessment for offshore cage culture

This study establishes a practical methodology for storm damage risk assessment and zoning for offshore cage culture by superimposing the vulnerability theory onto hydrodynamic modeling. The peak significant wave height is statistically correlated to the normalized fatigue load criteria at specified loading cycles to classify the destruction duration and damage state during storm events. The yield damage of the flotation pipe under cyclical wave oscillations was identified as the major failure mechanism of the sea cage. The structural failure risk would significantly decrease to 4.5-m waves, which is much lower than the manufacturing standard due to cumulative damage in a relatively short operation time. The wave-circulation model was applied to hindcast 112 high-impact typhoon scenarios in the study area for the return period analysis of the storm wave field. The damage risk distribution of the cage culture was mapped across the landscape to increase storm strength according to the vulnerability classification. The effectiveness of island shielding was explicitly revealed, and the leeward side was overall less risky as the return period increased, with the safe area shrinking inshore. For extreme conditions over a 100-year return period, the shield performance of leeward bays varied significantly due to the shoreline profile differences. Some existing cage deployment locations are at-risk relative to the structural resistance capability, whereas other unrecognized areas might be suitable for cage culture. These findings imply the necessity of storm risk assessment before proactive prevention measures and deployment zoning. The methodology may also be adapted to storm risk predictions for other facilities in the coastal ocean.

Risk perceptions and economic incentives for mitigating windstorm damage to housing

ABSTRACT Mitigation measures such as window shutters can substantially reduce windstorm damage to housing. However, the cost-effectiveness of wind mitigation measures remains unclear when considering influencing factors such as financial protection via insurance, individual risk perceptions and planning time horizons. Economic incentives may also be provided to motivate homeowners to invest in mitigation. In this study, the installation of cyclone-rated window shutters as a mitigation measure for homeowners in Australia is used as a case study. A life-cycle cost analysis in conjunction with a rank-dependent expected utility model are employed to identify economic incentives that are financially attractive to homeowners with different perceived risks and planning time horizons. The effect of home insurance is also taken into account. The results suggest that, as expected, the economic incentives needed to promote window shutters among homeowners decrease with the perceived storm damage risk and planning time horizon. A rebate for shutter installation cost or a discounted insurance premium have been found to be feasible economic incentives considering a typical planning time horizon of ten years. Statistical surveys are needed in future work to calibrate the parameters within the rank-dependent utility model to better represent the risk perceptions of different groups of homeowners.

The Environmental Health Impact of Hurricane Katrina on New Orleans.

Hurricane Katrina caused unprecedented flood damage to New Orleans, Louisiana, and has been the costliest hurricane in US history. We analyzed the environmental and public health outcomes of Hurricane Katrina by using Internet searches to identify epidemiological, sociodemographic, and toxicological measurements provided by regulatory agencies.Atmospheric scientists have now warned that global warming will increase the proportion of stronger hurricanes (categories 4-5) by 25% to 30% compared with weaker hurricanes (categories 1-2).With the new $14.6 billion Hurricane Storm Damage Risk Reduction System providing a 100-year storm surge-defensive wall across the Southeast Louisiana coast, New Orleans will be ready for stronger storms in the future.

Storm protection services

Coastal Protection![Figure][1] Coastal mangrove forests near Krabi, Thailand PHOTO: CRYSTITE RF/ALAMY STOCK PHOTO The tropics are at increasing risk of storm damage as the climate warms—a major worry, as coasts also concentrate human populations. Many coastlines in the tropics are, or once were, bordered by mangrove woodland. Mangroves colonize and stabilize the intertidal zone, not only providing habitats for terrestrial and marine organisms but also buffering storm surges, winds, and saline intrusion. However, these forests are at risk owing to land reclamation for building, agriculture, and other economic activities. Hochard et al. calculated the global value of mangroves in protecting human activities against tropical cyclone damage. From 23 mangrove-fringed countries, they observed human activity by satellite mapping of nighttime light. Regions with narrow (6-meter) strips of mangrove suffer greater permanent economic loss over the next 6 years than do communities protected by 25 meters of mangroves or more, despite disaster-mitigation responses. This work underscores the importance of restoring natural infrastructure for the benefit of vulnerable communities, as well as biodiversity. Proc. Natl. Acad. Sci. U.S.A. 116 , 12232 (2019). [1]: pending:yes

Mapping the risk of winter storm damage using GIS-based fuzzy logic

Abiotic and biotic factors that cause damage to forest trees also threaten the sustainability of forest resources. Although winter storms can be one of the most damaging forces, very few studies have focused on winter storm damage in Turkey. To prevent or minimize storm damage, we must evaluate the factors that influence the degree of damage and develop storm risk maps for the forested areas. Here, a GIS-based mathematical model (fuzzy logic) was used to develop such a risk map by considering risk factors such as tree species, tree age, crown density, site quality, topographical features (elevation, slope, aspect), climatic variables (wind, precipitation), and soil depth. The Alabarda Forest Enterprise Chief within the borders of Tavsanli Forest Enterprise Directorate was selected as the study area due to high occurrence of storm damage in the region during winter 2015–2016. For model verification, the risk map of storm damage was compared to the actual areal distribution of storm damage reported by the Enterprise Directorate. The model based on fuzzy logic indicated that slightly more than half of the study area (52.49%) was under very low storm damage risk, 28.12% was under low risk and 19.19% was classified as high risk. A very small portion of the total study area was classified as very high risk. These results indicated a close relation with the storm damage map generated using Tavsanli FED records. The results revealed that the most effective risk predictors for overall storm damage risk were wind direction and speed, followed by slope and site quality factors.

Impacts on forest management and forest state in southern Sweden 10 years after the storm Gudrun

Abstract About 70 million m3 was damaged by the storm Gudrun that hit southern Sweden in January 2005, i.e. almost as much as the normal annual cut for the whole country. To establish any differences in forest state and forest management before and after the storm, measures such as growing stock, annual growth, age-class distribution, choice of species in regeneration and cleaning and thinning activities were studied for the area affected and the area unaffected by the storm. For all analyses, sample plots from the Swedish National Forest Inventory were used. Results based on mean values for the periods 2000–2004/2006–2010/2012–2016 showed that the total growing stock for the damaged area decreased significantly by ~30 million m3 directly after the storm but has now recovered to the same level as before the storm. Therefore, it seems clear that forest owners and forest managers made rational choices when aiming to restore the forest area. As expected , the annually cleaned area and the area in immediate need of cleaning increased significantly in the Gudrun area after the storm. No other significant changes in behaviour to reduce future storm damage risk could be detected.

Pumping Up Flood Defenses

Completed in April 2018, the $731-million Permanent Canal Closures and Pumps project represents the final component of the overall Hurricane and Storm Damage Risk Reduction System that serves the g...

Recent emergence of CAT5 tropical cyclones in the South Indian Ocean

The IBTrACS global best track data set endorsed by the World Meteorological Organization provides a valuable global record of tropical cyclone genesis, track and intensity, and spans 1842 to the present. The record is significantly more robust from the late 1970s onwards, as it is supported by satellite imagery. These records indicate that the first tropical cyclone in the South Indian Ocean to intensify to CAT5 status did so in 1994. This date is significantly later than the first CAT5 storms recorded in the IBTrACS database for the Atlantic Ocean (1924) and the North Pacific (1951) recorded from ship records, and half a decade later than those of the North Indian Ocean (1989) and South Pacific (1988), captured from satellite imagery. Following this late emergence, in the period 1990–2000, eight CAT5 tropical cyclones were recorded for the South Indian Ocean. A further four have been recorded for the period 2010–2015. This recent emergence of tropical cyclones attaining category five intensity in the South Indian Ocean is of significance for the forecasting of tropical cyclone landfall and the anticipation of storm damage for the developing economies that characterise the region. Although an increase in tropical cyclone intensity is frequently projected under global climate change scenarios, the dynamics for the South Indian Ocean have remained poorly understood. Notable are early results indicating an increased frequency and poleward migration of these CAT5 storms, concurrent with a poleward migration in the position of the 26.5 °C, 28 °C and 29 °C sea surface temperature isotherms in the South Indian Ocean.Significance:
 
 Category 5 tropical cyclones, the strongest category of storms, have only recently emerged in the South Indian Ocean. Since 1989, their frequency of occurrence has increased. This increase poses a heightened risk of storm damage for the South Indian Ocean Island States and the countries of the southern African subcontinent as a result of the strong winds, heavy rainfall and storm surges associated with these storms, and the large radial extent at category 5 strength.

Impacts of climate change, weather extremes and alternative strategies in managed forests

ABSTRACTThe growth rate of most tree species in boreal forests will increase with changing climate. This increase is counterbalanced by an increased risk of damage due to extreme weather events. It is believed that the risk of storm damage will increase over time, especially if forests continue to be managed as they are today. In this study, a new landscape-level hybrid forest growth model 3PG-Heureka was developed and simulations were performed to predict the damage caused by storm events in Kronoberg county, over a period of 91 years (2010–2100) with different alternative management regimes under various climatic scenarios (historic, RCP4.5 and RCP8.5). The results indicate that damage caused by storm events could drastically reduce the annual volume increment and annual net revenue obtained from forest landscapes if current forest management regimes are used. These problems can be reduced by adopting alternative management strategies involving avoiding thinning, shorter rotation periods and planting alternative tree species. Alternative management strategies could potentially improve annual volume increments and net revenue obtained while reducing storm-felling. Planting Scots pine instead of Norway spruce across the landscape to minimize storm damage is predicted to be less effective than reducing rotation periods.

The Role of Highly-Resolved Gust Speed in Simulations of Storm Damage in Forests at the Landscape Scale: A Case Study from Southwest Germany

Routinely collected booking records of salvaged timber from the period 1979–2008 were used to empirically model the (1) storm damage probability; (2) proportions of storm-damaged timber and (3) endemic storm damage risk in the forest area of the German federal state of Baden-Wuerttemberg by applying random forests. Results from cross-validated predictor importance evaluation demonstrate that the relative impact of modeled gust speed fields on the predictive accuracy of the random forests models was greatest compared to the impact of forest and soil features. Forest areas prone to storm damage occurring within a period of five years were mainly located in mountainous upland regions where maximum gust speed exceeds 31 m/s in a five-year return period and conifers dominate the tree species composition. While mean storm damage probability continuously increased with increasing statistical gust speed proportions of storm-damaged timber peaked at a statistical maximum gust speed value of 29 m/s occurring in a five-year return period. Combining the statistical gust speed field with daily gust speed fields of two exceptional winter storms improved model accuracy and considerably increased the explained variance. Endemic storm damage risk was calculated from endemic storm damage probability and proportions of endemically storm-damaged timber. In combination with knowledge of local experts the storm damage risk modeled in a 50 m × 50 m resolution raster dataset can easily be used to identify areas prone to storm damage and to adapt silvicultural management regimes to make forests more windfirm.

Guidance for Developing Coastal Vulnerability Metrics

ABSTRACT Wamsley, T.V.; Collier, Z.A.; Brodie, K.; Dunkin, L.M.; Raff, D., and Rosati, J.D., 2015. Guidance for developing coastal vulnerability metrics. Appropriate coastal zone management and storm-damage risk reduction requires the assessment of vulnerability in natural and human environments. Confusion arises, however, as vulnerability is conceptualized in many different ways and is closely related to other concepts such as risk and resilience. This paper defines nomenclature, presents a conceptual definition of vulnerability, and lays out a proposed conceptual approach for identifying and defining meaningful metrics to ensure a complete assessment of coastal vulnerability. While the focus of this paper is developing metrics for assessing vulnerability to coastal storms, the approach is valid for a wide range of systems and hazards at multiple scales and can explicitly consider the impacts of climate change. The approach is demonstrated through application to a simply coupled human-environment system ...

Peanut Cultivar Response to Tomato Spotted Wilt over Five Planting Dates

ABSTRACT Tomato spotted wilt virus (TSWV) is vectored by thrips and causes an economically damaging peanut disease in the southeastern U.S. Peanut planting was traditionally initiated when soil temperatures became favorable in April. Planting in the latter two thirds of May is recommended to avoid thrips feeding and reduce tomato spotted wilt (TSW) incidence. This regime concentrates work load for growers and buying points, increases risk of tropical storm damage during harvest, and may contribute to reduced crop maturity. Improved TSW tolerance in cultivars may allow growers to plant earlier spreading risk and work load. Cultivars Georgia Green, Georgia-03L, AT 3085RO, and Flavor Runner 458 were compared with the advanced breeding line EXP 271516 based on peanut foliar condition, pod yield, and grade in 2008 and 2009 in Dawson, Georgia and Headland, Alabama. Peanuts were planted at five planting dates starting in late April through early June each year. Disease incidence was variable according to year, location, and planting date. Planting dates in April and early May resulted in higher TSW incidence. Foliar TSW ratings for the susceptible cultivar Flavor Runner 458 ranged between 48–96% at harvest. Georgia Green had 10–65% TSW incidence while maintaining yields between 3,315–5,440 kg/ha. Other cultivars had better TSW tolerance resulting in higher yield under more intense TSW pressure. Planting in the middle of May or later resulted in the highest yields. Cultivars with improved tolerance to TSW maintained yield above 4,490 kg/ha in early plantings. These results indicate the least risky management is possible by planting the most TSW tolerant genotypes during the current recommended planting dates.

Forest management facing climate change - an ecosystem model analysis of adaptation strategies

To adapt to climate change, forest managers request information on management options for obtaining environmental, societal and economic goals. In this study, we assess the potential of adaptive forest management to influence the productivity and storm sensitivity of nemoral and boreal forest. The forest growth across Sweden over the 21st century was simulated by the ecosystem model LPJ-GUESS, comparing four management options: 1) default forest management, 2) shorter rotation period 3) increased fraction of broadleaved trees and 4) continuous cover forestry. The simulations indicated that a management strategy implemented by a majority of forest owners can have a large-scale effect on the standing volume and risk taking. The modelled risk of storm damage, expressed as the combined effect of tree properties, ground frost and wind load, was higher in the southern than in the northern part of the country due to latitudinal variations in all three components. We conclude that whereas the probability of a significant volume loss increase with the age of a forest, the calculated economic loss can be as high in young and mid-age forest stands. To reduce the risk of storm damage and fulfil a variety of management goals, a portfolio of adaptation strategies is needed. It should include active measures such as tree-species mixtures to spread the risks and shorter rotation periods of highly exposed stands, as well as reactive measures such as salvage and sanitary cutting to reduce the risk of subsequent spruce bark beetle outbreaks.

Hurricane Katrina and the Inner Harbor Navigation Canal Lake Borgne Surge Barrier

Louisiana’s Inner Harbor Navigation Canal (IHNC) Lake Borgne Surge Barrier is the central feature of the world’s largest Hurricane and Storm Damage Risk Reduction System (HSDRSS), As well as the la...

Storm damage of Douglas-fir unexpectedly high compared to Norway spruce

Since storm damage has a large impact on forest management in Central Europe, we investigated the main storm risk factors for two important conifer species, Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco) and Norway spruce (Picea abies [L.] Karst.). We compared general storm damage levels of Douglas-fir and Norway spruce, the latter being known to have high storm risk among European tree species. Generalized linear mixed models and boosted regression trees were applied to recorded storm damage of individual trees from long-term experimental plots in southwest Germany. This included two major winter storm events in 1990 and 1999. Over 40 candidate predictors were tested for their explanatory power for storm damage and summarized into predictor categories for further interpretation. The two most important categories associated with storm damage were timber removals and topographic or site information, explaining between 18 and 54 % of storm damage risk, respectively. Remarkably, general damage levels were not different between Douglas-fir and Norway spruce. Under current forest management approaches, Douglas-fir may be considered a species with high storm risk in Central Europe, comparable to that of Norway spruce.

European extra-tropical storm damage risk from a multi-model ensemble of dynamically-downscaled global climate models

Abstract. Uncertainty in the return levels of insured loss from European wind storms was quantified using storms derived from twenty-two 25 km regional climate model runs driven by either the ERA40 reanalyses or one of four coupled atmosphere-ocean global climate models. Storms were identified using a model-dependent storm severity index based on daily maximum 10 m wind speed. The wind speed from each model was calibrated to a set of 7 km historical storm wind fields using the 70 storms with the highest severity index in the period 1961–2000, employing a two stage calibration methodology. First, the 25 km daily maximum wind speed was downscaled to the 7 km historical model grid using the 7 km surface roughness length and orography, also adopting an empirical gust parameterisation. Secondly, downscaled wind gusts were statistically scaled to the historical storms to match the geographically-dependent cumulative distribution function of wind gust speed. The calibrated wind fields were run through an operational catastrophe reinsurance risk model to determine the return level of loss to a European population density-derived property portfolio. The risk model produced a 50-yr return level of loss of between 0.025% and 0.056% of the total insured value of the portfolio.

Storm Damage Risk Reduction

The United States and other countries spend millions of dollars annually on storm damage repairs. Most of this work is to repair existing roads and transportation facilities. Large amounts of repair work have been done on the low-volume road network of the U.S. Department of Agriculture Forest Service over the past three decades, particularly in the Pacific Northwest. Agencies cannot afford to build roads to be 100% storm resistant, or stormproof, but they can be made more storm resistant. Measures can be taken to reduce the risk of storm damage from any given event. The objectives of this paper are to identify the assessment process and discuss treatments that can be used to reduce road damage and environmental impacts. Storm damage risk reduction first involves an assessment of any given road, the natural setting, the value of the road, traffic use, and design standards. Because resources are always limited, roads in areas of high risk, in steep terrain, or in areas subject to flooding, and the most important roads, from both the infrastructure and environmental standpoints, should be prioritized for preventative work. Storm damage risk reduction measures include many maintenance, drainage improvement, and structural tasks. Roadway surface drainage structures such as ditches, cross drains, and rolling dips need to be clean, properly armored, and properly spaced to prevent the concentration of water. Drainage-crossing structures such as bridges, fords, and culverts need to have adequate capacity or at least be clear of debris, well armored, scour resistant, and functioning properly. Trash racks can be added. Marginally stable road cuts and fills can be modified and reinforced with vegetation or soil bioengineering treatments. Staying current with road maintenance is critical for proper road function during storms.