Data Glossary
Defined Terms
- Agriculture Exposure Value
- Annualized Frequency
- Avalanche
- Building Exposure Value
- Census Blocks
- Census Tracts
- Coastal Flooding
- Cold Wave
- Community Resilience
- Consequence Types
- Drought
- Earthquake
- Expected Annual Loss
- Expected Annual Loss Rate
- Exposure
- Fishnet Grid
- Geographic Information Systems (GIS)
- Hail
- Heat Wave
- Historic Loss Ratio
- Hurricane
- Ice Storm
- Landslide
- Lightning
- Natural Hazard Risk
- Natural Hazards
- Population Exposure
- Raster
- Risk Value
- Riverine Flooding
- Social Vulnerability
- Strong Wind
- Tornado
- Tsunami
- Value of Statistical Life (VSL)
- Volcanic Activity
- Wildfire
- Winter Weather
Agriculture Exposure Value
Agriculture exposure value refers to the estimated dollar value of crops and livestock determined to be exposed to a hazard according to a hazard-specific methodology.
Related Terms
Expected Annual Loss, Exposure, Historic Loss Ratio, Natural Hazard Risk
Annualized Frequency
Annualized frequency is a natural hazard incidence factor for Expected Annual Loss, a risk component of the National Risk Index. It is the expected frequency or probability of a hazard occurrence per year.
Related Terms
Avalanche, Coastal Flooding, Cold Wave, Drought, Earthquake, Expected Annual Loss, Exposure, Hail, Heat Wave, Historic Loss Ratio, Hurricane, Ice Storm, Landslide, Lightning, Natural Hazard Risk, Natural Hazards, Riverine Flooding, Strong Wind, Tornado, Tsunami, Volcanic Activity, Wildfire, Winter Weather
Avalanche
An Avalanche is a mass of snow in swift motion traveling down a mountainside.
Related Terms
Building Exposure Value
Building exposure value refers to the dollar value of the buildings determined to be exposed to a hazard according to a hazard-specific methodology.
Related Terms
Expected Annual Loss, Exposure, Historic Loss Ratio, Natural Hazard Risk
Census Blocks
Census blocks are statistical areas bounded by visible features—such as streets, roads, streams, and railroad tracks—and nonvisible boundaries—such as selected property lines and city, township, school district, and county boundaries. Census blocks are the smallest geographic area for which the U.S. Census Bureau collects and tabulates decennial Census data.
Related Terms
Census Tracts
Census tracts are small, relatively permanent statistical subdivisions of a county or equivalent entity that is updated by local participants prior to each decennial Census as part of the U.S. Census Bureau’s Participant Statistical Areas Program. The primary purpose of Census tracts is to provide a stable set of geographic units for the presentation of statistical data.
Related Terms
Coastal Flooding
Coastal Flooding is when water inundates or covers normally dry coastal land as a result of high or rising tides or storm surges.
Related Terms
Hurricane, Landslide, Natural Hazards, Strong Wind, Tsunami, Winter Weather
Cold Wave
A Cold Wave is a rapid fall in temperature within 24 hours and extreme low temperatures for an extended period.
Related Terms
Community Resilience
Community Resilience is a consequence reduction risk component and community risk factor that represents the ability of a community to prepare for anticipated natural hazards, adapt to changing conditions, and withstand and recover rapidly from disruptions.
Related Terms
Expected Annual Loss, Natural Hazard Risk, Natural Hazards, Social Vulnerability
Consequence Types
Consequences of natural hazard occurrences are categorized into three different types: buildings, population, and agriculture.
Related Terms
Expected Annual Loss, Exposure, Historic Loss Ratio, Natural Hazard Risk
Drought
A Drought is a deficiency of precipitation over an extended period of time resulting in a water shortage.
Related Terms
Earthquake
An Earthquake is a shaking of the earth's surface by energy waves emitted by slowly moving tectonic plates overcoming friction with one another underneath the earth's surface.
Related Terms
Expected Annual Loss
Expected Annual Loss (EAL) is a natural hazards component of the National Risk Index that represents the average loss in dollars to buildings, population, and/or agriculture (consequence types) each year due to natural hazards.
Related Terms
Agriculture Exposure Value, Annualized Frequency, Avalanche, Building Exposure Value, Coastal Flooding, Cold Wave, Community Resilience, Drought, Earthquake, Exposure, Hail, Heat Wave, Historic Loss Ratio, Hurricane, Ice Storm, Landslide, Lightning, Natural Hazard Risk, Natural Hazards, Population Exposure, Riverine Flooding, Social Vulnerability, Strong Wind, Tornado, Tsunami, Value of Statistical Life (VSL), Volcanic Activity, Wildfire, Winter Weather
Expected Annual Loss Rate
Expected Annual Loss Rate is a measure of relative natural hazard intensities independent of the community's exposure value. They represent the average percentage losses to buildings, population, and/or agriculture (consequence types) each year due to natural hazards.
Exposure
Exposure is a natural hazard consequence factor for Expected Annual Loss, a risk component of the National Risk Index. It is the representative value of buildings, population, or agriculture potentially exposed to a natural hazard occurrence.
Related Terms
Agriculture Exposure Value, Annualized Frequency, Avalanche, Building Exposure Value, Coastal Flooding, Cold Wave, Drought, Earthquake, Expected Annual Loss, Hail, Heat Wave, Historic Loss Ratio, Hurricane, Ice Storm, Landslide, Lightning, Natural Hazard Risk, Natural Hazards, Population Exposure, Riverine Flooding, Strong Wind, Tornado, Tsunami, Value of Statistical Life (VSL), Volcanic Activity, Wildfire, Winter Weather
Fishnet Grid
A fishnet grid is a geographic information system (GIS) feature containing a net of rectangular cells that can be used for sampling locations or as aggregation areas.
Related Terms
Geographic Information Systems (GIS)
A geographic information system (GIS) is a database system with software that can analyze and display data in a visual environment using digitized maps and tables. Maps and data may be layered, displayed, edited, and analyzed in a wide variety of ways.
Related Terms
Hail
Hail is a form of precipitation that occurs during thunderstorms when raindrops, in extremely cold areas of the atmosphere, freeze into balls of ice before falling towards the earth's surface.
Related Terms
Heat Wave
A Heat Wave is a period of abnormally and uncomfortably hot and unusually humid weather typically lasting two or more days with temperatures outside the historical averages for a given area.
Related Terms
Historic Loss Ratio
Historic loss ratio (HLR) is a natural hazard consequence factor of the Expected Annual Loss component of the National Risk Index. It is a hazard- and county-specific estimate of the percentage of the exposed consequence type (building value, population, or agriculture value) expected to be lost due to a hazard occurrence.
Related Terms
Agriculture Exposure Value, Annualized Frequency, Avalanche, Building Exposure Value, Coastal Flooding, Cold Wave, Drought, Earthquake, Expected Annual Loss, Exposure, Hail, Heat Wave, Hurricane, Ice Storm, Landslide, Lightning, Natural Hazard Risk, Natural Hazards, Population Exposure, Riverine Flooding, Strong Wind, Tornado, Tsunami, Value of Statistical Life (VSL), Volcanic Activity, Wildfire, Winter Weather
Hurricane
A Hurricane is a tropical cyclone or localized, low-pressure weather system that has organized thunderstorms but no front (a boundary separating two air masses of different densities) and maximum sustained winds of at least 74 miles per hour (mph).
Related Terms
Coastal Flooding, Hail, Lightning, Natural Hazards, Riverine Flooding, Strong Wind, Tornado
Ice Storm
An Ice Storm is a freezing rain situation (rain that freezes on surface contact) with significant ice accumulations of 0.25 inches or greater.
Related Terms
Landslide
A Landslide is the movement of a mass of rock, debris, or earth down a slope.
Related Terms
Coastal Flooding, Earthquake, Hurricane, Natural Hazards, Riverine Flooding, Tsunami, Volcanic Activity, Winter Weather
Lightning
Lightning is a visible electrical discharge or spark of electricity in the atmosphere between clouds, the air, and/or the ground often produced by a thunderstorm.
Related Terms
Natural Hazard Risk
Natural hazard risk is the potential for negative impacts as a result of a natural hazard.
Related Terms
Agriculture Exposure Value, Annualized Frequency, Avalanche, Building Exposure Value, Coastal Flooding, Cold Wave, Community Resilience, Drought, Earthquake, Expected Annual Loss, Exposure, Hail, Heat Wave, Historic Loss Ratio, Hurricane, Ice Storm, Landslide, Lightning, Natural Hazards, Population Exposure, Riverine Flooding, Social Vulnerability, Strong Wind, Tornado, Tsunami, Value of Statistical Life (VSL), Volcanic Activity, Wildfire, Winter Weather
Natural Hazards
Natural hazards are environmental phenomena that impact societies and the human environment.
Related Terms
Annualized Frequency, Avalanche, Coastal Flooding, Cold Wave, Community Resilience, Drought, Earthquake, Expected Annual Loss, Exposure, Hail, Heat Wave, Historic Loss Ratio, Hurricane, Ice Storm, Landslide, Lightning, Natural Hazard Risk, Natural Hazards, Riverine Flooding, Social Vulnerability, Strong Wind, Tornado, Tsunami, Value of Statistical Life (VSL), Volcanic Activity, Wildfire, Winter Weather
Population Exposure
Population exposure refers to the estimated number of people determined to be exposed to a hazard according to a hazard-specific methodology.
Raster
A raster consists of a matrix of cells (or pixels) organized into rows and columns (or a grid) where each cell contains a value representing information. The cell values represent the phenomenon portrayed by the raster dataset, such as category or magnitude.
Related Terms
Risk Value
Risk value represents the average loss in dollars to buildings, population, and/or agriculture (consequence types) each year to a community due to natural hazards adjusted based on the community's Social Vulnerability and Community Resilience.
Related Terms
Community Resilience, Expected Annual Loss, Social Vulnerability
Riverine Flooding
Riverine Flooding is when streams and rivers exceed the capacity of their natural or constructed channels to accommodate water flow and water overflows the banks, spilling out into adjacent low-lying, dry land.
Related Terms
Coastal Flooding, Hurricane, Landslide, Natural Hazards, Tsunami, Winter Weather
Social Vulnerability
Social vulnerability is a consequence enhancing risk component and community risk factor that represents the susceptibility of social groups to the adverse impacts of natural hazards, including disproportionate death, injury, loss, or disruption of livelihood.
Related Terms
Community Resilience, Expected Annual Loss, Natural Hazard Risk, Natural Hazards
Strong Wind
Strong Wind consists of damaging winds, often originating from thunderstorms, that are classified as exceeding 58 miles per hour (mph).
Related Terms
Coastal Flooding, Hurricane, Natural Hazards, Tornado, Winter Weather
Tornado
A Tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground and is visible only if it forms a condensation funnel made up of water droplets, dust and debris.
Related Terms
Tsunami
A Tsunami is a wave, or series of waves, generated by an Earthquake, Landslide, volcanic eruption, or even a large meteor hitting the ocean and causing a rise or mounding of water at the ocean surface. A Tsunami can travel across open ocean at about 500 miles per hour (mph), and slow down to about 30 mph as it approaches land, causing it to grow significantly in height.
Related Terms
Coastal Flooding, Earthquake, Landslide, Natural Hazards, Population Exposure, Riverine Flooding, Volcanic Activity
Value of Statistical Life (VSL)
Monetary value of preventing one statistical death. Within the National Risk Index, a VSL of $11.6M per fatality or 10 injuries is used to monetize population losses so that a total expected annual loss value can be computed that considers losses to buildings, population, and agriculture.
Related Terms
Expected Annual Loss, Exposure, Historic Loss Ratio, Natural Hazard Risk, Population Exposure
Volcanic Activity
Volcanic Activity occurs via vents that act as a conduit between the Earth’s surface and inner layers, and erupt gas, molten rock and volcanic ash when gas pressure and buoyancy drive molten rock upward and through zones of weakness in the Earth’s crust.
Related Terms
Wildfire
A Wildfire is an unplanned fire burning in natural or wildland areas such as forests, shrub lands, grasslands, or prairies.
Related Terms
Drought, Heat Wave, Lightning, Natural Hazards, Volcanic Activity
Winter Weather
Winter Weather consists of winter storm events in which the main types of precipitation are snow, sleet or freezing rain.
Related Terms
Avalanche, Coastal Flooding, Cold Wave, Ice Storm, Natural Hazards, Riverine Flooding, Strong Wind