Broad-scale climatic influences on rainfall thresholds for debris flows: Adapting thresholds for northern California to southern California

1997 ◽  
pp. 71-80 ◽  
Author(s):  
Raymond C. Wilson
Keyword(s):  
Debris Flows ◽  
Southern California ◽  
Northern California ◽  
Rainfall Thresholds ◽  
Broad Scale

scholarly journals California Floods Linked to Atmospheric Water Vapor “Rivers”

Eos ◽  
2017 ◽  
Author(s):  
Sarah Stanley
Keyword(s):  
Water Vapor ◽  
Debris Flows ◽  
Southern California ◽  
Flash Floods ◽  
Atmospheric Water Vapor ◽  
Northern California ◽  
Atmospheric Water ◽  
Heavy Rains

Narrow atmospheric streams of water vapor that deliver heavy rains are more commonly associated with floods and debris flows in northern California than with flash floods in southern California.

Uncertainty in debris flow rainfall thresholds

2021 ◽  
Author(s):  
Matteo Berti ◽  
Alessandro Simoni
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Measurement Errors ◽  
Critical Conditions ◽  
Model Parameters ◽  
Average Intensity ◽  
Rainfall Thresholds ◽  
Sources Of Uncertainty ◽  
Time Space ◽  
Physically Based

<p>Rainfall is the most significant factor for debris flows triggering. Water is needed to saturate the soil, initiate the sediment motion (regardless of the mobilization mechanism) and transform the solid debris into a fluid mass that can move rapidly downslope. This water is commonly provided by rainfall or rainfall and snowmelt. Consequently, most warning systems rely on the use of rainfall thresholds to predict debris flow occurrence. Debris flows thresholds are usually empirically-derived from the rainfall records that caused past debris flows in a certain area, using a combination of selected precipitation measurements (such as event rainfall P, duration D, or average intensity I) that describe critical rainfall conditions. Recent years have also seen a growing interest in the use of coupled hydrological and slope stability models to derive physically-based thresholds for shallow landslide initiation.</p><p>In both cases, rainfall thresholds are affected by significant uncertainty. Sources of uncertainty include: measurement errors; spatial variability of the rainfall field; incomplete or uncertain debris flow inventory; subjective definition of the “rainfall event”; use of subjective criteria to define the critical conditions; uncertainty in model parameters (for physically-based approaches). Rainfall measurement is widely recognized as a main source of uncertainty due to the extreme time-space variability that characterize intense rainfall events in mountain areas. However, significant errors can also arise by inaccurate information reported in landslide inventories on the timing of debris flows, or by the criterion used to define triggering intensities.</p><p>This study analyzes the common sources of uncertainty associated to rainfall thresholds for debris flow occurrence and discusses different methods to quantify them. First, we give an overview of the various approaches used in the literature to measure the uncertainty caused by random errors or procedural defects. These approaches are then applied to debris flows using real data collected in the Dolomites (Northen Alps, Itay), in order to estimate the variabilty of each single factor (precipitation, triggering timing, triggering intensity..). Individual uncertainties are then combined to obtain the overall uncertain of the rainfall threshold, which can be calculated using the classical method of “summation in quadrature” or a more effective approach based on Monte Carlo simulations. The uncertainty budget allows to identify the biggest contributors to the final variability and it is also useful to understand if this variability can be reduced to make our thresholds more precise.</p><p> </p>

scholarly journals Postcards from the future

2013 ◽  
Vol 3 (4) ◽  
pp. 12-26 ◽  
Author(s):  
Kristin Miller
Keyword(s):  
Los Angeles ◽  
Science Fiction ◽  
Southern California ◽  
Northern California ◽  
Bay Area ◽  
The Future ◽  
Science Fiction Films ◽  
Photo Essay ◽  
The Way

This article contemplates the way Northern and Southern California have been used in science fiction films since the 1970s. Continuing a trend the author traces to the 1940s novels Earth Abides and Ape and Essence, Northern California represents possible utopian futures while Southern California represents dystopia. The article includes a photo essay featuring science fiction film stills held up against their filming locations in Los Angeles and the Bay Area.

Objective definition of rainfall intensity–duration thresholds for the initiation of post-fire debris flows in southern California

Landslides ◽  
2012 ◽  
Vol 10 (5) ◽  
pp. 547-562 ◽  
Author(s):  
Dennis M. Staley ◽  
Jason W. Kean ◽  
Susan H. Cannon ◽  
Kevin M. Schmidt ◽  
Jayme L. Laber
Keyword(s):  
Debris Flows ◽  
Southern California ◽  
Rainfall Intensity ◽  
Fire Debris ◽  
Definition Of

Rainfall thresholds for the occurrence of debris flows in the Jiangjia Gully, Yunnan Province, China

2015 ◽  
Vol 195 ◽  
pp. 335-346 ◽  
Author(s):  
Jianqi Zhuang ◽  
Peng Cui ◽  
Gonghui Wang ◽  
Xiaoqing Chen ◽  
Javed Iqbal ◽  
...  
Keyword(s):  
Debris Flows ◽  
Yunnan Province ◽  
Rainfall Thresholds ◽  
Jiangjia Gully

Review of the bivalve genus Plicatula from Cretaceous and lower Cenozoic strata of California and Baja California

1997 ◽  
Vol 71 (2) ◽  
pp. 287-298 ◽  
Author(s):  
Richard L. Squires ◽  
Louella R. Saul
Keyword(s):  
New Species ◽  
Los Angeles ◽  
Lower Cretaceous ◽  
Southern California ◽  
Upper Cretaceous ◽  
Baja California ◽  
Middle Eocene ◽  
Baja California Sur ◽  
Northern California ◽  
Three New Species

The Cretaceous and early Cenozoic species of the shallow-marine, warm-water bivalve Plicatula from California (United States) and Baja California (Mexico) are reviewed, and three new species are named. All of these species are representatives of Plicatula and not of the closely related taxon Harpax, which is associated with high-latitude and cool-water regions. The earliestknown Cretaceous species of Plicatula from the study area is P. variata Gabb, 1864, from Lower Cretaceous (Hauterivian Stage) strata in northern California, and our studies show it to be conspecific with Plicatula onoensis Anderson, 1958.Plicatula allisoni new species is from Lower Cretaceous (Albian Stage) strata in Baja California, Mexico. Plicatula modjeskaensis new species is from Upper Cretaceous (Turonian Stage) strata in the Santa Ana Mountains, southern California. A possible new species from the same strata is also mentioned. A poorly preserved specimen of Plicatula? sp. is known from Upper Cretaceous (upper Campanian to lower Maastrichtian) strata in northern California.The only Paleocene species of Plicatula from the study area is P. ostreiformis Stanton, 1896, from lower Paleocene strata of Lake County, northern California, and our studies show it to be conspecific with Ostrea buwaldana Dickerson, 1914. The only previously described Eocene species of Plicatula from the study area is P. juncalensis Squires, 1987, from lower middle Eocene (“Capay Stage”) strata of Los Angeles County, southern California. Plicatula surensis new species is from middle lower Eocene (“Capay Stage”) strata in Baja California Sur, Mexico. In addition, there is a Plicatula? sp. from Eocene strata of Baja California Sur, Mexico.Although Plicatula is of uncommon occurrence north of Baja California, its thermophilic trait makes it useful in recognizing periods of warm climate.

Catastrophic disturbances in headwater streams: the long-term ecological effects of debris flows and debris floods in the Klamath Mountains, northern California

2010 ◽  
Vol 67 (10) ◽  
pp. 1596-1610 ◽  
Author(s):  
Matthew R. Cover ◽  
Juan A. de la Fuente ◽  
Vincent H. Resh
Keyword(s):  
Debris Flow ◽  
Debris Flows ◽  
Headwater Streams ◽  
Ecological Effects ◽  
Ecosystem Structure ◽  
Northern California ◽  
Klamath Mountains ◽  
Mountainous Landscapes ◽  
Debris Floods

Debris flows and debris floods are catastrophic disturbances in steep, mountainous landscapes throughout the world, but little is known about the long-term ecological effects of these events on headwater streams. In 10 basins (10–20 km2) in the Klamath Mountains, northern California, USA, we used a space-for-time substitution to infer the long-term (10–100 years) effects of debris flows on stream ecosystem structure. Debris flows mobilized sediment and wood and removed riparian vegetation from large portions of channel networks. Stream temperatures were significantly warmer in streams that had recent debris flows (<10 years ago). Large wood, benthic organic matter, and detritivorous stoneflies were all very sparse in recent debris flow streams, suggesting that allochthonous energy pathways took decades to recover. Rainbow trout ( Oncorhynchus mykiss ) were abundant in recent debris flow streams, but populations of other vertebrates such as coastal giant salamander ( Dicamptodon tenebrosus ) and coastal tailed frog ( Ascaphus truei ) were virtually absent. Increased frequencies of catastrophic debris flows associated with forest management practices can have significant negative impacts on aquatic biodiversity in forested, mountainous landscapes.

Northeast Pacific Cretaceous record ofPyropsis(Neogastropoda: Pyropsidae) and paleobiogeography of the genus

2011 ◽  
Vol 85 (6) ◽  
pp. 1199-1215 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
Southern California ◽  
Upper Cretaceous ◽  
New World ◽  
Vancouver Island ◽  
Northern California ◽  
Shallow Marine ◽  
Northeast Pacific ◽  
Siliciclastic Rocks ◽  
First Time ◽  
Warm Temperate

The neogastropod genusPyropsisConrad, 1860 (family Pyropsidae Stephenson, 1941) is recognized for the first time from Upper Cretaceous shallow-marine siliciclastic rocks in the region extending from Vancouver Island, British Columbia southward to southern California. Four new species were detected:Pyropsis aldersoni(earliest Coniacian, southern California),Pyropsis californica(early Coniacian, northern California),Pyropsis louellae(late Coniacian or early Santonian, northern California), andPyropsis grahami(late early Campanian, Vancouver Island).A critical review of the global reports ofPyropsis, a genus that has been commonly confused with other genera (especiallyTudiclaRöding, 1798), establishes thatPyropsishad an amphitropical distribution and lived in warm-temperate waters adjacent to a broad tropical realm. It is rare to uncommon wherever found, and its geologic range is middle Cenomanian to an age near the Cretaceous/Paleogene boundary (probably earliest Paleocene). It was moderately widespread before the Maastrichtian but was predominantly restricted to the New World during the Maastrichtian.

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