The ARkStorm (for Atmospheric River 1,000) is a hypothetical megastorm, whose proposal is based on repeated historical occurrences of atmospheric rivers and other major rain events first developed and published by the Multi-Hazards Demonstration Project (MHDP) of the United States Geological Survey (USGS) in 2010. [1] An updated model was published as ARkStorm 2.0 in 2022. [2]
The ARkStorm 1.0 scenario describes an extreme storm that devastates much of California, causing up to $725 billion in losses (mostly due to flooding and erosion), and affecting a quarter of California's homes. The scenario projects impacts of a storm that would be significantly less intense (25 days of rain) than the California storms that occurred between December 1861 and January 1862 (43 days). That event dumped nearly 10 feet (3.0 m) of rain in parts of California. [3] [4]
USGS sediment research in the San Francisco Bay Area, Santa Barbara Basin, Sacramento Valley, and the Klamath Mountain region found that "megastorms" have occurred in the years: 212, 440, 603, 1029, c. 1300, 1418, 1605, 1750, 1810, and, most recently, 1861–1862. Based on the intervals of these known occurrences, ranging from 51 to 426 years, for a historic recurrence of, on average, every 100–200 years. [3]
Geologic evidence indicates that several of the previous events were more intense than the one in 1861–1862, particularly those in 440, 1418, 1605, and 1750, each of which deposited a layer of silt in the Santa Barbara Basin more than one inch (2.5 cm) thick. The largest event was the one in 1605, which left a layer of silt two inches (5 cm) thick, indicating that this flood was at least 50% more powerful than any of the others recorded.
The conditions built into the scenario are "two super-strong atmospheric rivers, just four days apart, one in Northern California and one in Southern California, and one of them stalled for an extra day". [5]
The ARkStorm 1.0 scenario would have the following effects:
This update, [7] with parts of the research on impacts still ongoing,[ when? ] has examined how climate change is expected to increase the risk of severe flooding from a hypothetical ARkStorm, with runoff 200% to 400% above historical values for the Sierra Nevada in part due to a decrease in the portion of precipitation that falls as snow, as well as an increase in the amount of water that storms can carry. The likelihood of the event outlined in the ARkStorm scenario is now once every 25–50 years, with projected economic losses of over $1 trillion (or more than five times that of Hurricane Katrina). [8]
| Odds of Occurring | ||||||
|---|---|---|---|---|---|---|
| Scenario | Annual Risk | 1920 Risk | 2071–2080 Risk (worst case with RCP 8.5) | Days | Precipitation | Damage (if it happened today) |
| Great Flood of 1862 | 1.2–1.6% | 0.5–0.7% | 3.4%–4.8% | 43+ | 10 feet (3.0 metres) | |
| ARkStorm | 2–4% | 25+ | US$1 trillion+ (2010 estimate in 2022 dollars) | |||
Current flood maps in the U.S. rarely take recent projections from projects like ARkStorm into account, especially FEMA's maps, which many decision-makers have relied on. [9] Land owners, flood insurers, governments and media outlets often use maps like FEMA's that still fail to represent many significant risks due to: 1) using only historical data (instead of incorporating climate change models), 2) the omission of heavy rainfall events, and 3) lack of modeling of flooding in urban areas. More robust and up-to-date models, like the First Street Foundation's riskfactor.com, [10] should better represent true flood risk though it is unclear if that model, for example, incorporates any ARkStorm science.
Government agencies may decide how much risk to accept, and how much risk to mitigate. The Netherlands' approach to flood control, for example, plans for 1 in 10,000 year events in heavily-populated areas [11] and 1 in 4,000 year events in less well-populated areas.
A flood is an overflow of water that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding. Examples for human changes are land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees. Global environmental issues also influence causes of floods, namely climate change which causes an intensification of the water cycle and sea level rise. For example, climate change makes extreme weather events more frequent and stronger. This leads to more intense floods and increased flood risk.
A natural disaster is the very harmful impact on a society or community after a natural hazard event. Some examples of natural hazard events include avalanches, droughts, earthquakes, floods, heat waves, landslides, tropical cyclones, volcanic activity and wildfires. Additional natural hazards include blizzards, dust storms, firestorms, hails, ice storms, sinkholes, thunderstorms, tornadoes and tsunamis. A natural disaster can cause loss of life or damage property. It typically causes economic damage. How bad the damage is depends on how well people are prepared for disasters and how strong the buildings, roads, and other structures are. Scholars have been saying that the term natural disaster is unsuitable and should be abandoned. Instead, the simpler term disaster could be used. At the same time the type of hazard would be specified. A disaster happens when a natural or human-made hazard impacts a vulnerable community. It results from the combination of the hazard and the exposure of a vulnerable society.
Extreme weather includes unexpected, unusual, severe, or unseasonal weather; weather at the extremes of the historical distribution—the range that has been seen in the past. Extreme events are based on a location's recorded weather history. They are defined as lying in the most unusual ten percent. The main types of extreme weather include heat waves, cold waves and heavy precipitation or storm events, such as tropical cyclones. The effects of extreme weather events are economic costs, loss of human lives, droughts, floods, landslides. Severe weather is a particular type of extreme weather which poses risks to life and property.
The Federal Emergency Management Agency (FEMA) is an agency of the United States Department of Homeland Security (DHS), initially created under President Jimmy Carter by Presidential Reorganization Plan No. 3 of 1978 and implemented by two Executive Orders on April 1, 1979. The agency's primary purpose is to coordinate the response to a disaster that has occurred in the United States and that overwhelms the resources of local and state authorities. The governor of the state in which the disaster occurs must declare a state of emergency and formally request from the President that FEMA and the federal government respond to the disaster. The only exception to the state's gubernatorial declaration requirement occurs when an emergency or disaster takes place on federal property or to a federal asset—for example, the 1995 bombing of the Alfred P. Murrah Federal Building in Oklahoma City, Oklahoma, or the Space Shuttle Columbia in the 2003 return-flight disaster.
Pineapple Express is a specific recurring atmospheric river both in the waters immediately northeast of the Hawaiian Islands and extending northeast to any location along the Pacific coast of North America. It is a non-technical term and a meteorological phenomenon. It is characterized by a strong and persistent large-scale flow of warm moist air, and the associated heavy precipitation. A Pineapple Express is an example of an atmospheric river, which is a more general term for such relatively narrow corridors of enhanced water vapor transport at mid-latitudes around the world.
The National Flood Insurance Program (NFIP) is a program created by the Congress of the United States in 1968 through the National Flood Insurance Act of 1968. The NFIP has two purposes: to share the risk of flood losses through flood insurance and to reduce flood damages by restricting floodplain development. The program enables property owners in participating communities to purchase insurance protection, administered by the government, against losses from flooding, and requires flood insurance for all loans or lines of credit that are secured by existing buildings, manufactured homes, or buildings under construction, that are located in the Special Flood Hazard Area in a community that participates in the NFIP. U.S. Congress limits the availability of National Flood Insurance to communities that adopt adequate land use and control measures with effective enforcement provisions to reduce flood damages by restricting development in areas exposed to flooding.
Hurricane preparedness in New Orleans has been an issue since the city's early settlement because of its location.
Typhoon Vera, also known as the Isewan Typhoon, was an exceptionally intense tropical cyclone that struck Japan in September 1959, becoming the strongest and deadliest typhoon on record to make landfall on the country, as well as the only one to do so as a Category 5 equivalent storm. The storm's intensity resulted in catastrophic damage of unparalleled severity and extent, and was a major setback to the Japanese economy, which was still recovering from World War II. In the aftermath of Vera, Japan's disaster management and relief systems were significantly reformed, and the typhoon's effects would set a benchmark for future storms striking the country.
Disaster risk reduction aims to make disasters less likely to happen. The approach, also called DRR or disaster risk management, also aims to make disasters less damaging when they do occur. DRR aims to make communities stronger and better prepared to handle disasters. In technical terms, it aims to make them more resilient or less vulnerable. When DRR is successful, it makes communities less the vulnerable because it mitigates the effects of disasters. This means DRR can make risky events fewer and less severe. Climate change can increase climate hazards. So development efforts often consider DRR and climate change adaptation together.
Climate change in California has resulted in higher than average temperatures, leading to increased occurrences of droughts and wildfires. Over the next few decades in California, climate change is likely to further reduce water availability, increase wildfire risk, decrease agricultural productivity, and threaten coastal ecosystems. The state will also be impacted economically due to the rising cost of providing water to its residents along with revenue and job loss in the agricultural sector. Economic impacts also include inflation from rising insurance premiums, energy costs and food prices. California has taken a number of steps to mitigate impacts of climate change in the state.
The Great Flood of 1862 was the largest flood in the recorded history of California, Oregon, and Nevada, inundating the western United States and portions of British Columbia and Mexico. It was preceded by weeks of continuous rains and snows that began in Oregon in November 1861 and continued into January 1862. This was followed by a record amount of rain from January 9–12, and contributed to a flood that extended from the Columbia River southward in western Oregon, and through California to San Diego, as well as extending as far inland as the Washington Territory, the Utah Territory, and the western New Mexico Territory.
An atmospheric river (AR) is a narrow corridor or filament of concentrated moisture in the atmosphere. Other names for this phenomenon are tropical plume, tropical connection, moisture plume, water vapor surge, and cloud band.
The California flood of 1605 was a massive flood that submerged large portions of present-day California. The megaflood was a result of sustained major rain storms across the region, enhanced by an unusually powerful atmospheric river. The flooding affected the indigenous peoples of California, in pre-industrial advancement populations.
Megastorm may refer to:
Flooding in 2017 affected parts of California in the first half of the year. Northern California saw its wettest winter in almost a century, breaking the record set in 1982–83. The same storm systems also flooded parts of western Nevada and southern Oregon. The damage was estimated at $1.55 billion ($1,926,663,046 today), including damage to California roads and highways estimated at more than $1.05 billion.
Hurricane Harvey was a devastating tropical cyclone that made landfall on Texas and Louisiana in August 2017, causing catastrophic flooding and more than 100 deaths. It is tied with 2005's Hurricane Katrina as the costliest tropical cyclone on record, inflicting $125 billion in damage, primarily from catastrophic rainfall-triggered flooding in the Houston metropolitan area and Southeast Texas; this made the storm the costliest natural disaster recorded in Texas at the time. It was the first major hurricane to make landfall in the United States since Wilma in 2005, ending a record 12-year span in which no hurricanes made landfall at the intensity of a major hurricane throughout the country. In a four-day period, many areas received more than 40 inches (1,000 mm) of rain as the system slowly meandered over eastern Texas and adjacent waters, causing unprecedented flooding. With peak accumulations of 60.58 in (1,539 mm), in Nederland, Texas, Harvey was the wettest tropical cyclone on record in the United States. The resulting floods inundated hundreds of thousands of homes, which displaced more than 30,000 people and prompted more than 17,000 rescues.
The effects of climate change on extreme weather events is requiring the insurance industry in the United States to recalculate risk assessments for various types of insurance. From 1980 to 2005, private and federal government insurers in the United States paid $320 billion in constant 2005 dollars in claims due to weather-related losses while the total amount paid in claims annually generally increased, and 88% of all property insurance losses in the United States from 1980 to 2005 were weather-related. Annual insured natural catastrophe losses in the United States grew 10-fold in inflation-adjusted terms from $49 billion in total from 1959 to 1988 to $98 billion in total from 1989 to 1998, while the ratio of premium revenue to natural catastrophe losses fell six-fold from 1971 to 1999 and natural catastrophe losses were the primary factor in 10% of the approximately 700 U.S. insurance company insolvencies from 1969 to 1999 and possibly a contributing factor in 53%.
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