Washout (erosion)

washoutwashoutswashed out
A severe washout can become a landslide, or cause a dam break in an earthen dam. Like other forms of erosion, most washouts can be prevented by vegetation whose roots hold the soil and/or slow the flow of surface and underground water. Deforestation increases the risk of washouts. Retaining walls and culverts may be used to try to prevent washouts, although particularly severe washouts may even destroy these if they are not large or strong enough. In road and rail transport, a washout is the result of a natural disaster where the roadbed is eroded away by flowing water, usually as the result of a flood.

List of floods

List of notable floods19752013 flood
*The 2009 Fiji floods are responsible for at least 16 deaths in the islands * On early April 2014, the Cyclone Ita caused disastrous flooding across the Solomon Islands, killing at least 21 people. * In November 2007, Cyclone Guba, a slow moving storm caused deadly flooding in Papua New Guinea. * The 2017 Peru flood was a natural disaster in Peru in which more than 100 000 homes were demolished, over 100 bridges washed out, and multiple roadways rendered inoperable. Over 70 people have lost their lives as a result of the flooding. * The 1959 flood in Uruguay was provoked by an overflow in the Río Negro.


earthquakesseismic activityseismic
Large waves produced by an earthquake or a submarine landslide can overrun nearby coastal areas in a matter of minutes. Tsunamis can also travel thousands of kilometers across open ocean and wreak destruction on far shores hours after the earthquake that generated them. Ordinarily, subduction earthquakes under magnitude 7.5 do not cause tsunamis, although some instances of this have been recorded. Most destructive tsunamis are caused by earthquakes of magnitude 7.5 or more. Floods may be secondary effects of earthquakes, if dams are damaged. Earthquakes may cause landslips to dam rivers, which collapse and cause floods.

List of mass evacuations

largest evacuations
October 2007 – California wildfires forced more than 900,000 people in Southern California to evacuate, making it the largest evacuation in California's history and the largest evacuation for fire in United States history. May 2008 – 2008 Sichuan earthquake: Approximately 200,000 people are evacuated in Beichuan County, China because of flooding fears after a landslide created dam became unstable. August 2008 – At least 1.9 million people were evacuated from coastal Louisiana, including New Orleans, for Hurricane Gustav. In western Cuba, at least 300,000 people were evacuated.

United States

Victory in the Mexican–American War resulted in the 1848 Mexican Cession of California and much of the present-day American Southwest. The California Gold Rush of 1848–49 spurred migration to the Pacific coast, which led to the California Genocide and the creation of additional western states. After the American Civil War, new transcontinental railways made relocation easier for settlers, expanded internal trade and increased conflicts with Native Americans. For half a century, the rapidly declining buffalo struck an existential blow to many Plains Indians' culture.


tsunamistidal waveseaquake
Another landslide-tsunami event occurred in 1963 when a massive landslide from Monte Toc entered the Vajont Dam in Italy. The resulting wave surged over the 262 m (860 ft) high dam by 250 metres (820 ft) and destroyed several towns. Around 2,000 people died. Scientists named these waves megatsunamis. Some geologists claim that large landslides from volcanic islands, e.g. Cumbre Vieja on La Palma in the Canary Islands, may be able to generate megatsunamis that can cross oceans, but this is disputed by many others. In general, landslides generate displacements mainly in the shallower parts of the coastline, and there is conjecture about the nature of large landslides that enter the water.


volcanicvolcanoesvolcanic igneous activity
They are named Decade Volcanoes because the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction (the 1990s). The 16 current Decade Volcanoes are |} The Deep Earth Carbon Degassing Project, an initiative of the Deep Carbon Observatory, monitors nine volcanoes, two of which are Decade volcanoes. The focus of the Deep Earth Carbon Degassing Project is to use Multi-Component Gas Analyzer System instruments to measure CO 2 /SO 2 ratios in real-time and in high-resolution to allow detection of the pre-eruptive degassing of rising magmas, improving prediction of volcanic activity.


thunderstormssevere thunderstormelectrical storm
Flash flooding is the process where a landscape, most notably an urban environment, is subjected to rapid floods. These rapid floods occur more quickly and are more localized than seasonal river flooding or areal flooding and are frequently (though not always) associated with intense rainfall. Flash flooding can frequently occur in slow-moving thunderstorms and is usually caused by the heavy liquid precipitation that accompanies it. Flash floods are most common in densely populated urban environments, where few plants and bodies of water are present to absorb and contain the extra water.


earthfilldamsconcrete-face rock-fill dam
Natural disasters such as earthquakes and landslides frequently create landslide dams in mountainous regions with unstable local geology. Historical examples include the Usoi Dam in Tajikistan, which blocks the Murghab River to create Sarez Lake. At 560 m high, it is the tallest dam in the world, including both natural and man-made dams. A more recent example would be the creation of Attabad Lake by a landslide on Pakistan's Hunza River. Natural dams often pose significant hazards to human settlements and infrastructure.

Global storm activity of 2010

2009–10 North American winter stormsGlobal storm activity of early 2010Global storm activity of mid-2010
On January 22, the sixth storm caused heavy rainfall in parts of Los Angeles, leading to additional flooding. 500 people were evacuated from a small village in La Paz County, Arizona due to a flash flood. Freshly fallen snow blanketed the north side of the San Gabriel Mountains on the morning of January 23, 2010, northwest of Wrightwood, California, after the sixth storm had left. Snow was also reported in many parts of California. During that week, the storms dropped 8 in to 10 in of rain in Los Angeles. In California, the storms dropped a maximum total of 20 in of rain in the higher elevations of the Sierra Nevada, while a maximum total of 90 in of snow was recorded at Mammoth Lakes.

List of natural disasters in the United States

natural disaster in U.S.natural disastersnatural disasters in the history of the United States
This list of United States natural disasters is a list of notable natural disasters which occurred in the United States from 1816 to 2017. In May 2018, an exhaustive overview of recurrent natural disasters in the United States since 1900, based largely on government data, including data from NASA, FEMA and others, was reported in The New York Times. Due to inflation, the monetary damage estimates are not comparable. Unless otherwise noted, the year given is the year in which the currency's valuation was calculated. * List of disasters in the United States by death toll. List of wildfires in the United States.

Hurricane Liza

Liza1976's LizaHurricane Liza (1976)
In all, Liza brought a total of $100 million in damage in Baja California Sur, which receives catastrophic flooding from hurricanes every 50 years or so. The hurricane was considered the worst natural disaster in the history of the peninsula, which at the time held 130,000 occupants. Furthermore, Liza was at that time considered the worst hurricane to affect the entire country in the 20th century. Hurricane Liza caused extensive damage and loss of life in the Mexican state of Baja California Sur.


riverineriparianleft bank
Flooding is a natural part of a river's cycle. The majority of the erosion of river channels and the erosion and deposition on the associated floodplains occur during the flood stage. In many developed areas, human activity has changed the form of river channels, altering magnitudes and frequencies of flooding. Some examples of this are the building of levees, the straightening of channels, and the draining of natural wetlands. In many cases human activities in rivers and floodplains have dramatically increased the risk of flooding. Straightening rivers allows water to flow more rapidly downstream, increasing the risk of flooding places further downstream.

Tropical cyclone

hurricanetropical stormhurricanes
Storm/Flood and Hurricane/Typhoon Response–NIOSH of the CDC. U.S. Billion-dollar Weather and Climate Events.


wreckagerock debriscoarse
In geology, debris usually applies to the remains of geological activity including landslides, volcanic explosions, avalanches, mudflows or Glacial lake outburst floods (Jökulhlaups) and moraine, lahars, and lava eruptions. Geological debris sometimes moves in a stream called a debris flow. When it accumulates at the base of hillsides, it can be called "talus" or "scree". In mining, debris called attle usually consists of rock fragments which contain little or no ore.

Mediterranean climate

warm-summer Mediterranean climateMediterraneanCsb
Aquatic communities in Mediterranean climate regions are adapted to a yearly cycle in which abiotic (environmental) controls of stream populations and community structure dominate during floods, biotic components (e.g. competition and predation) controls become increasingly important as the discharge declines, and environmental controls regain dominance as environmental conditions become very harsh (i.e. hot and dry); as a result, these communities are well suited to recover from droughts, floods, and fires. Aquatic organisms in these regions show distinct long-term patterns in structure and function, and are also highly sensitive to the effects of climate change.


Excessive rain during short periods of time can cause flash floods. Cultural attitudes towards rain differ across the world. In temperate climates, people tend to be more stressed when the weather is unstable or cloudy, with its impact greater on men than women. Rain can also bring joy, as some consider it to be soothing or enjoy the aesthetic appeal of it. In dry places, such as India, or during periods of drought, rain lifts people's moods. In Botswana, the Setswana word for rain, pula, is used as the name of the national currency, in recognition of the economic importance of rain in its country, since it has a desert climate.

Types of volcanic eruptions

volcanic eruptioneruptionvolcanic eruptions
The nature of glaciovolcanism dictates that it occurs at areas of high latitude and high altitude. It has been suggested that subglacial volcanoes that are not actively erupting often dump heat into the ice covering them, producing meltwater. This meltwater mix means that subglacial eruptions often generate dangerous jökulhlaups (floods) and lahars. The study of glaciovolcanism is still a relatively new field. Early accounts described the unusual flat-topped steep-sided volcanoes (called tuyas) in Iceland that were suggested to have formed from eruptions below ice.

Landslide dam

debris dambarrier lakelandslide lake
The water impounded by a landslide dam may create a dam reservoir (lake) that may last from short times to several thousand years. Because of their rather loose nature and absence of controlled spillway, landslide dams frequently fail catastrophically and lead to downstream flooding, often with high casualties. A common failure scenario is overflowing with subsequent dam breach and erosion by the overflow stream. Landslide dams are responsible for two types of flooding: backflooding (upstream flooding) upon creation and downstream flooding upon failure.


Short radio episode California Glaciers from The Mountains of California by John Muir, 1894. California Legacy Project. Dyanamics of Glaciers. GletscherVergleiche.ch – Before/After Images by Simon Oberli.

Natural hazard

natural hazardsnaturalhazard
is an online tool that provides an overview of the hazards from eight natural hazards (river floods, earthquakes, water scarcity, cyclones, coastal floods, tsunamis, volcanoes and landslides) developed by the Global Facility for Disaster Reduction and Recovery in partnership with other institutions.

Thomas Fire

Thomas wildfireThomasThomas Fire (2017)
The area, along with most of Southern California, experienced the driest March-through-December period on record. While November is the typical beginning of the rainy season in California, the first measurable rain for the area fell on January 8, 2018, more than a month into the fire. With the natural vegetation burnt, flash floods and mudflows damaged homes in Montecito when the rains arrived. Evacuations were ordered or anticipated for neighborhoods that sit below areas recently burned by the Thomas Fire and other wildfires. By January 10, at least 21 people had been killed by the sudden flooding and debris flows that followed the heavy rains, which also destroyed over 100 homes.


Drainage basin management covers water storage, in the form of reservoirs, and floods protection. Water quality includes the chemistry of water in rivers and lakes, both of pollutants and natural solutes. Calculation of rainfall. Calculating surface runoff and precipitation. Determining the water balance of a region. Determining the agricultural water balance. Designing riparian restoration projects. Mitigating and predicting flood, landslide and drought risk. Real-time flood forecasting and flood warning. Designing irrigation schemes and managing agricultural productivity. Part of the hazard module in catastrophe modeling. Providing drinking water.

Coastal flooding

coastal floodCoastal Flood Warningcyclone-generated wave washover
Breaching is where the barrier is broken down or destroyed by waves allowing the seawater to extend inland and flood the areas. 1) wind setup. 2) barometric setup. 3) wave setup. Management strategies for dealing with the forced abandonment of coastal settlements. Quantifying the effectiveness of natural buffering systems, such as mangroves, against coastal flooding. Better engineering design and practices or alternative mitigation strategies to engineering. 2004 Indian Ocean earthquake and tsunami. Canterbury Bight. Coastal flood advisory, watch, warning (U.S.). Coastal management. Flash flood. Flood barrier. Hurricane Katrina. Intergovernmental Panel on Climate Change.


lacustrinefreshwater lakenatural freshwater lake
These are typically classifiable as either playas or playa lakes because they are periodically flooded by either rain or flood events and then dry up during drier intervals, leaving accumulations of brines and evaporitic minerals. A salt pan (saltpan) is either an undrained small shallow natural depression in which water accumulates and evaporates leaving a salt deposit or the shallow lake of brackish water occupying a salt pan. This term is also used for a large pan for recovering salt by evaporation. A saline pan is a name for an ephemeral saline lake which precipitates a bottom crust that is subsequently modified during subaerial exposure.