Spatial and temporal changes in climate extremes over northwestern North America: the influence of internal climate variability and external forcing

Mahmoudi, Mohammad Hasan; Najafi, Mohammad Reza; Singh, Harsimrenjit; Schnorbus, M.

doi:10.1007/s10584-021-03037-9

Cited by 9 publications

(4 citation statements)

References 69 publications

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“…Yet, hydrologic variables are interdependent and do not typically share the same marginal distribution. Mahmoudi et al and Xu et al [26,27] evaluated the compound effects of storm surges and precipitation on a coastal city's flood risk. Both studies highlighted that the combined impacts of surges and precipitation far exceed their individual effects; this is often overlooked in current flood defense designs.…”

Section: Introductionmentioning

confidence: 99%

Compound Impact of Storm Surge and Flood Characteristics in Coastal Area Based on Copula

Zhu,

Zhang,

Zhu

2024

Water

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In low-lying coastal areas, the interplay of various factors including precipitation, river flow, and storm surge can lead to greater influence on floods when they occur simultaneously. The copula method was used in this study to investigate the bivariate flood risk of compounding storm surge and river discharge events in the Pearl River Delta (PRD). Our results indicate that while the correlation between storm surge and flood peak (S-Q) was weak, there was a strong dependence between the pairs of storm surge–flood volume (S-V) and storm surge–flood duration (S-D). For these three pairs, the Clayton copula was the optimal function for S-Q, while the Frank copula was the optimal function for S-V and S-D, respectively. When the flood volume exceeds 2.0 × 104 m3/s and the flood duration is more than 10 days, the bivariate hydrologic risk for S-V and S-D is observed to decrease rapidly. Furthermore, the failure probability (FP) would be underestimated when the combined impact of river flow and storm surge is ignored in coastal flood risk assessment. Such bivariate hydrologic risk analysis implies that when determining design values in coastal flood risk assessment, the combined impact of river flow and storm surge should be taken into account.

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Section: Introductionmentioning

confidence: 99%

Compound Impact of Storm Surge and Flood Characteristics in Coastal Area Based on Copula

Zhu,

Zhang,

Zhu

2024

Water

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“…The majority of populated areas in Canada are in tornado‐prone (Sills et al, 2012) and flood‐prone regions, specifically urban areas (Abebe et al, 2018; Mahmoudi et al, 2021). On 22 June 2007, Canada's most intense and the only F 5 category tornado hit Elie, Manitoba (Environment Canada, 2017).…”

Section: Introductionmentioning

confidence: 99%

Probabilistic assessment of concurrent tornado and storm‐related flash flood events

Ngui

Najafi

Souza

et al. 2023

Intl Journal of Climatology

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The concurrent occurrence of extreme events can significantly impact societies and infrastructure systems, especially when the instructions provided to the exposed communities demand conflicting responses. In this study, a probabilistic assessment of concurrent tornado and storm-related flash flood (TORFF) events is performed across southern Canada. We quantify the interdependencies between tornadoes and flash floods (extreme precipitation as proxy) using ground-based and reanalysis datasets. Windspeed values corresponding to tornado events, categorized based on the recorded Fujita rating, are derived through a resampling approach. The TORFF events are clustered and the corresponding bivariate probability distributions of the resampled windspeed and associated precipitation are characterized based on Copula framework. The individual and joint return periods of concurrent tornadoes and flash floods are then assessed under the AND (when both variables exceed predefined thresholds), OR (when either one of the two variables exceeds predefined thresholds), and conditional hazard scenarios across Canada. Results show positive strong dependencies between resampled windspeed and associated precipitation in Saskatchewan, and weaker dependencies followed by Alberta, Manitoba, Ontario, and Quebec. The Saskatchewan region shows the highest risk underestimation considering the independence scenario compared to the other regions. Higher precipitation is also expected during extreme windspeed, as observed in the conditional assessment of precipitation given windspeed. This study provides insights for more robust recurrence interval estimation for tornadoes and flash floods to aid in emergency planning of evacuation decision-making process.

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“…Communities and infrastructure systems in Canada's coastal areas, across the Atlantic, Pacific, and the Great Lakes, are at risk of flooding caused by extreme precipitation, river overflows, storm surges, and tides (Bush & Lemmen, 2019; Mahmoudi et al., 2021). Some examples include Hurricane Juan which hit eastern Canada and Nova Scotia resulting in an economic loss of $200 million in September 2003, Hurricane Dorian in eastern Canada (September 2019) with $78.9 million in damage, and Hurricane Teddy affecting Nova Scotia in September 2020.…”

Section: Introductionmentioning

confidence: 99%

Multivariate Analysis of Compound Flood Hazard Across Canada's Atlantic, Pacific and Great Lakes Coastal Areas

Pirani

Najafi

2022

Earth's Future

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Flooding, as the most common natural hazard in the world (Kundzewicz et al., 2014), has affected more than two billion people and caused approximately USD 656 billion of damage between 1998 and 2017 (AghaKouchak et al., 2020;Wallemacq, 2018). From 1980 to 2019, flood events have accounted for 41% of all the 17,300 weather-related events, 28% of 890,000 lives lost, 27% of USD 4,000 billion economic losses, and 10% of USD 1,300 billion insured losses worldwide (Golnaraghi et al., 2020). The frequency of flood events has been increasing from 1960 to 2013, globally (Tanoue et al., 2016). Similarly, the magnitude of flooding shows increases in some regions around the world (Do et al., 2020). Around 0.8-1.1 million people experience flooding and its devastating socioeconomic consequences each year (Muis et al., 2016), especially the coastal communities. The population of the low-lying coastal areas was approximately 625 million in 2000, which is anticipated to reach 949 million by the 2030s and 1.4 billion by 2060s (Neumann et al., 2015), indicating larger exposure to different Abstract Compound flooding, caused by the simultaneous or successive occurrence of two or more flood mechanisms, is mainly associated with extreme precipitation, river overflows, and storm tides across coastal areas. The interdependencies between these components can increase the risks of flood impacts, threatening coastal communities and infrastructure systems. This study quantifies the corresponding multivariate hazard over Canada's coastal areas by characterizing the dependencies between multiple drivers of flooding based on the C-vine copula statistical approach. The joint return periods of compound flooding considering the AND, OR, and Kendall scenarios are estimated and the corresponding failure probabilities are assessed. Further, the compound hazard ratio (CHR) index is applied to quantify possible under-or overestimations of the flood hazards when individual drivers are assessed independently. Analyses are performed at 41 locations across the Atlantic, Pacific, and the Great Lakes coasts, and the uncertainties are quantified based on the Bayes theorem.Results show that at approximately 50% of locations (mostly at the Great Lakes), the flood hazard associated with the AND scenario increases considerably when the dependencies are characterized compared to the (unrealistic) independence scenario, indicating the potential for compound flooding in these regions. Besides, at more than half of the studied locations, the CHR index exceeds one highlighting the interrelationships between drivers of flooding. The results of this study provide a deeper understanding of the flood mechanisms and their interdependencies across Canada's coasts, which support the development of resilient structures and improved coastal flood management. Plain Language SummaryApproximately half of the global population lives within 200 km of coastlines. The communities and infrastructure systems in the coastal environments are at risk of flooding caused by one or multipl...

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Spatial and temporal changes in climate extremes over northwestern North America: the influence of internal climate variability and external forcing

Cited by 9 publications

References 69 publications

Compound Impact of Storm Surge and Flood Characteristics in Coastal Area Based on Copula

Compound Impact of Storm Surge and Flood Characteristics in Coastal Area Based on Copula

Probabilistic assessment of concurrent tornado and storm‐related flash flood events

Multivariate Analysis of Compound Flood Hazard Across Canada's Atlantic, Pacific and Great Lakes Coastal Areas

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