scholarly journals Atmospheric rivers drive flood damages in the western United States

2019 ◽  
Vol 5 (12) ◽  
pp. eaax4631 ◽  
Author(s):  
Thomas W. Corringham ◽  
F. Martin Ralph ◽  
Alexander Gershunov ◽  
Daniel R. Cayan ◽  
Cary A. Talbot
Keyword(s):  
United States ◽  
Fold Increase ◽  
The United States ◽  
Flood Damage ◽  
Western United States ◽  
Flood Insurance ◽  
The West ◽  
Atmospheric Rivers ◽  
Insurance Program ◽  
Flood Damages

Atmospheric rivers (ARs) are extratropical storms that produce extreme precipitation on the west coasts of the world’s major landmasses. In the United States, ARs cause significant flooding, yet their economic impacts have not been quantified. Here, using 40 years of data from the National Flood Insurance Program, we show that ARs are the primary drivers of flood damages in the western United States. Using a recently developed AR scale, which varies from category 1 to 5, we find that flood damages increase exponentially with AR intensity and duration: Each increase in category corresponds to a roughly 10-fold increase in damages. Category 4 and 5 ARs cause median damages in the tens and hundreds of millions of dollars, respectively. Rising population, increased development, and climate change are expected to worsen the risk of AR-driven flood damage in future decades.

scholarly journals A Climatology of 500-hPa Closed Lows in the Northeastern Pacific Ocean, 1948–2011

2014 ◽  
Vol 53 (6) ◽  
pp. 1578-1592 ◽  
Author(s):  
Nina S. Oakley ◽  
Kelly T. Redmond
Keyword(s):  
United States ◽  
Pacific Ocean ◽  
Interannual Variability ◽  
West Coast ◽  
The United States ◽  
Western United States ◽  
The West ◽  
Reanalysis Dataset ◽  
The Pacific ◽  
Northeastern Pacific

AbstractThe northeastern Pacific Ocean is a preferential location for the formation of closed low pressure systems. These slow-moving, quasi-barotropic systems influence vertical stability and sustain a moist environment, giving them the potential to produce or affect sustained precipitation episodes along the west coast of the United States. They can remain motionless or change direction and speed more than once and thus often pose difficult forecast challenges. This study creates an objective climatological description of 500-hPa closed lows to assess their impacts on precipitation in the western United States and to explore interannual variability and preferred tracks. Geopotential height at 500 hPa from the NCEP–NCAR global reanalysis dataset was used at 6-h and 2.5° × 2.5° resolution for the period 1948–2011. Closed lows displayed seasonality and preferential durations. Time series for seasonal and annual event counts were found to exhibit strong interannual variability. Composites of the tracks of landfalling closed lows revealed preferential tracks as the features move inland over the western United States. Correlations of seasonal event totals for closed lows with ENSO indices, the Pacific decadal oscillation (PDO), and the Pacific–North American (PNA) pattern suggested an above-average number of events during the warm phase of ENSO and positive PDO and PNA phases. Precipitation at 30 U.S. Cooperative Observer stations was attributed to closed-low events, suggesting 20%–60% of annual precipitation along the West Coast may be associated with closed lows.

A comparison of earthquake damage areas as a function of magnitude across the United States

1993 ◽  
Vol 83 (4) ◽  
pp. 1064-1080 ◽  
Author(s):  
G. A. Bollinger ◽  
M. C. Chapman ◽  
M. S. Sibol
Keyword(s):  
United States ◽  
North America ◽  
Ground Motion ◽  
Epicentral Distance ◽  
The United States ◽  
Western United States ◽  
Eastern North America ◽  
Similar Response ◽  
Eastern United States ◽  
The West

Abstract This study investigates the relationship between earthquake magnitude and the size of damage areas in the eastern and western United States. To quantify damage area as a function of moment magnitude (M), 149 MMI VI and VII areas for 109 earthquakes (88 in the western United States, 21 in the eastern United States and Canada) were measured. Regression of isoseismal areas versus M indicated that areas in the East were larger than those in the West, at both intensity levels, by an average 5 × in the M 4.5 to 7.5 range. In terms of radii for circles of equivalent area, these results indicate that damaging ground motion from shocks of the same magnitude extend 2 × the epicentral distance in eastern North America compared to the West. To determine source and site parameters consistent with the above results, response spectral levels for eastern North America were stochastically simulated and compared with response spectral ordinates derived from recorded strong ground motion data in the western United States. Stress-drop values of 200 bars, combined with a surficial 2-km-thick low velocity “sedimentary” layer over rock basement, produced results that are compatible with the intensity observations, i.e., similar response spectral levels in the east at approximately twice their epicentral distance in the western U.S. distance. These results suggest that ground motion modeling in eastern North America may need to incorporate source and site parameters different from those presently in general use. The results are also of importance to eastern U.S. hazard assessments as they require allowance for the larger damage areas in preparedness and mitigation programs.

scholarly journals Addressing Affordability in the National Flood Insurance Program

2014 ◽  
Vol 01 (01) ◽  
pp. 1450001 ◽  
Author(s):  
Carolyn Kousky ◽  
Howard Kunreuther
Keyword(s):  
United States ◽  
The United States ◽  
Hurricane Sandy ◽  
Flood Insurance ◽  
National Flood Insurance Program ◽  
Voucher Program ◽  
Insurance Program ◽  
Loan Program ◽  
Flood Prone Areas

There is often tension between setting insurance premiums that reflect risk and dealing with equity/affordability issues. The National Flood Insurance Program in the United States recently moved toward elimination of certain premium discounts, but this raised issues with respect to the affordability of coverage for homeowners in flood-prone areas. Ultimately, Congress reversed course and reinstated discounted rates for certain classes of policyholders. We examine the tension between risk-based rates and affordability through a case study of Ocean County, New Jersey, an area heavily damaged by Hurricane Sandy. We argue that the NFIP must address affordability, but that this should not be done through discounted premiums. Instead, we propose a means-tested voucher program coupled with a loan program for investments in hazard mitigation.

scholarly journals Improved Prediction of Atmospheric Rivers That Drive Flood Damages in the Western United States

2021 ◽  
Author(s):  
Cary A. Talbot ◽  
Tom Corringham ◽  
F. Martin Ralph ◽  
Alexander Gershunov ◽  
Daniel R. Cayan
Keyword(s):  
United States ◽  
Western United States ◽  
Atmospheric Rivers ◽  
Flood Damages

scholarly journals HURRICANE TIDE FREQUENCIES ON THE ATLANTIC COAST

1976 ◽  
Vol 1 (15) ◽  
pp. 51 ◽  
Author(s):  
Francis P. Ho
Keyword(s):  
United States ◽  
Gulf Of Mexico ◽  
New England ◽  
Atlantic Coast ◽  
The United States ◽  
Flood Insurance ◽  
Storm Tide ◽  
Insurance Program ◽  
Evacuation Plans ◽  
Warning Services

Hurricane surge Is a serious and not uncommon event along the Gulf of Mexico and Atlantic coasts of the United States. The most disastrous display of hurricane forces in recent decades was by Camille, which struck the Mississippi coast in 1969. The storm tide reached 24.6 ft MSL„ Reported storm tides on the Atlantic coast have reached elevations of 15 to 20 ft in Florida, Georgia, the Carolinas and New England. One of the latest coordinated efforts to alleviate losses from hurricanes — supplementing warning services, community preparedness, and evacuation plans— is the Flood Insurance Program.

scholarly journals Recent Changes in United States Extreme 3-Day Precipitation Using the R-CAT Scale

2020 ◽  
Vol 21 (6) ◽  
pp. 1207-1221 ◽  
Author(s):  
Maryam A. Lamjiri ◽  
F. Martin Ralph ◽  
Michael D. Dettinger
Keyword(s):  
United States ◽  
East Coast ◽  
The United States ◽  
Western United States ◽  
Eastern United States ◽  
Atmospheric Rivers ◽  
The Past ◽  
Extreme Precipitation Events ◽  
Precipitation Total ◽  
Precipitation Events

AbstractExtraordinary precipitation events have impacted the United States recently, including Hurricanes Harvey (2017) and Florence (2018), with 3-day precipitation totals larger than any others reported in the United States during the past 70 years. The rainfall category (R-CAT) scaling method is used here to document extreme precipitation events and test for trends nationally. The R-CAT scale uses thresholds of 3-day precipitation total in 100-mm increments (starting with 200 mm) that do not vary temporally or geographically, allowing for simple, intuitive comparisons of extremes over space and time. The paper that introduced the scale only required levels 1–4 to represent historical extremes, finding that R-CATs 3–4 strike the conterminous United States about as frequently as EF 4–5 tornadoes or category 3–5 hurricanes. Remarkably, Florence and Harvey require extending the scale to R-CAT 7 and 9, respectively. Trend analyses of annual maximum 3-day totals (1950–2019) here identify significant increases in the eastern United States, along with declines in Northern California and Oregon. Consistent with these results, R-CAT storms have been more frequent in the eastern, and less frequent in western, United States during the past decade compared to 1950–2008. Tropical storms dominate R-CAT events along the southeastern coast and East Coast with surprising contributions from atmospheric rivers, while atmospheric rivers completely dominate along the West Coast.

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