Glossary

100-year flood

A flood event that has a one percent chance of occurring in any given year.

1041 regulations

Regulations that allow Colorado local governments to retain control and develop permitting procedures and standards for development and/or projects with statewide impacts beyond their jurisdiction. 

500-year flood

A flood event that has a 0.2 percent chance of occurring in any given year.

Avalanche

A mass of snow, ice, and debris, flowing and sliding rapidly down a steep slope.

Avoidance

From a hazard mitigation perspective, planning and acting to eliminate exposure to hazard risk. 

Blizzard

A severe winter storm characterized by low temperatures, wind gusts of 35 mph or more, and falling and/or blowing snow that reduces visibility to ¼-mile or less for three or more hours.

Climate plan

A set of strategies intended to guide efforts for reducing greenhouse gas emissions.

Cluster subdivisions 

A close grouping of residential properties in a proposed subdivision where the rest of the land is designated for open space, recreation, or agriculture.

Community Rating System (CRS)

The National Flood Insurance Program’s voluntary incentive program that recognizes and encourages community floodplain management activities that exceed the minimum NFIP’s requirements.

Community wildfire protection plan

A plan developed in an area at-risk from wildland fire and involves interested parties, local government, local firefighting agencies, the state agency which oversees forest management, and federal land management agencies.

Comprehensive plan

A plan that expresses a community’s overarching vision, goals, objectives, policies, and strategies for future growth, development, and preservation of the community, protection of community assets, and provision of services. 

Conductive heat

Heat moving from one solid to another solid that has different temperature when touching each other. 

Conservation easements 

A restriction placed on a piece of property to protect its associated resources.

Convective heat

Heat transferred by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. 

COWRAP

Colorado Wildfire Risk Assessment Portal provides coarse-scale landscape level wildfire risk designation. Colorado State Forest Service’s (CSFS) uses COWRAP as the primary mechanism to deploy risk information and create awareness about wildfire issues across the state.

Debris flow

Mass of water and earth materials where more than half of the solids are larger than sand grains – rocks, stones, boulders – that flow down a stream, ravine, canyon, arroyo, or gulch. 

Density bonus

A zoning tool that permits developers to build at higher density than would normally be allowed in exchange for provision of a defined public benefit.

Deposition

The placing of the eroded material in a new location typically initiated by water or wind.

Development agreement

A contract between a local jurisdiction and a property owner that sets the standards and conditions that govern the development of the property.

Disaster Mitigation Act of 2000

Act that requires State, local, and tribal governments, as a condition of receipt of an increased Federal share for hazard mitigation measures, to develop and submit for approval a mitigation plan that outlines processes for identifying the natural hazards, risks, and vulnerabilities of the area under government jurisdiction. 

Drought

Shortage of water associated with a lack of precipitation.

Earthquake

Vibrations or shaking that is commonly created when large blocks of the earth’s crust move against one another, but can also be caused by volcanic or magmatic activity.

Ember transport

Small pieces of burning vegetation carried over a distance depending on weather conditions, topography, and species of vegetation.

Erosion 

Removal and simultaneous transportation of earth materials from one location to another by water, wind, waves, or moving ice. 

Expansive soils

Soils or soft bedrock that increase in volume as they get wet and shrink as they dry out. 

Extreme heat

Weather that is “substantially hotter and/or more humid than average for a location at that time of year.”

Fire Intensity Scale (FIS)

Used by Colorado Wildfire Risk Assessment Portal (COWRAP) to determine the potential fire intensity for a specified location. 

FIRMs

The Federal Emergency Management Agency’s (FEMA) Flood Insurance Rate Maps that identify special flood hazard areas.

Flash flood

Isolated, slow-moving thunderstorms with intense but isolated rainfall; the sudden failure or release by a dam, levee, retention basin or other stormwater control facility; or the obstruction of natural flows by ice jam or other blockages that cause backflow and overtopping.

Flood

An overflow of water that accumulates faster than surface absorbency allows or is greater than the normal carrying capacity of the stream channel. 

Floodplain

Lands adjacent to rivers, streams, lakes, and other water bodies that periodically flood and is a natural and inevitable occurrence that can be expected to take place based upon established recurrence intervals.

Future land use map

Illustrations of the desired development patterns and land uses for a community.

Geographic Information Systems (GIS)

A system designed to capture, store, manipulate, analyze, manage, and present all types of special or geographical data. 

Geologic hazards

An extreme natural event in the crust of the earth that pose a threat to life and property, e.g., earthquakes, volcanic eruptions, landslides, etc.

Greenhouse gas (GHG)

Gas(es) that contributes to the greenhouse effect by absorbing infrared radiation. 

Hazard Identification and Risk Assessment (HIRA)

A community’s written evaluation of its risk and vulnerability.

Hazardous material release

The spilling, disposal, or other form of discharge into the environment of any element or compound that, because of handling, storing, processing, or packaging, may have detrimental effects upon the public or environment.

Hazus

A nationally applicable standardized methodology that contains models for estimating potential physical, economic, and social losses from earthquakes, floods, and hurricanes.

Heat index

Measures the “apparent temperature” when considering both air temperature and humidity and is used by organizations like the National Weather Service to identify extreme heat days. 

Heavy snow

Snowfall accumulating to four inches or more in depth in 12 hours or less, or snowfall accumulating to six inches or more in depth in 24 hours or less.

High winds

Wind events with sustained wind speeds of 40 mph or greater and lasting for one hour or longer, or winds of 58 mph or greater for any duration.

Homogeneous forest

Forests of the same composition including trees of the same age, size, species etc.

Hydrophobic

Unable to absorb water.

Ice storm

Occasions when damaging accumulations of ice are expected during freezing rain situations.

Land acquisition 

Procurement of property.

Landslide

Downward and outward movement of slopes composed of natural rock, soils, artificial fills, or combinations thereof. 

Local Hazard Mitigation Plan

Consolidation of hazard-related information prepared by a community, including an assessment of potential hazards and risk, identification of vulnerable populations, and development of mitigation strategies. Local Hazard Mitigation Plans must be approved by state and federal officials and are effective for five years. 

Low-impact development

Stormwater management practice with the basic principle of managing rainfall at the source using uniformly distributed decentralized micro-scale controls.

Manufactured housing

A type of prefabricated housing that have similar zoning requirements and rights as stick-built housing.

Mitigation

Sustained action to reduce or eliminate long-term risk to life and property from hazards.

Modified Mercalli scale

A measure of an earthquake’s intensity.

Moratorium

A temporary prohibition of an activity. 

Mud flow

A mass of water and fine-grained earth materials that flow down a stream, ravine, canyon, arroyo, or gulch.

Overlay zoning 

A regulatory tool that creates a special zoning district placed over an existing base zone, thereby having special provisions in additional to existing provisions.

Parks and open space plan

A citywide and/or regional plan for parks, recreation, trails, and open space.

Response and recovery planning

A plan that prepares a city, region, or state to respond to a local hazard with recovery measures in place.

Richter scale

A measure of an earthquake’s magnitude.

Risk assessment

Identification of the potential impacts of hazards on a community’s physical, social, economic, and environmental assets and description of mitigation measures to reduce future risk. 

Riverine erosion

Long-term process whereby riverbanks and riverbeds are worn away.

Rockfall

Newly detached mass of rock falling from a cliff or down a very steep slope. 

Safe room

A room or space that is specially anchored and armored to provide near absolute protection during a tornado or wind storm.

Severe thunderstorm

A storm that produces a tornado, winds of at least 58 mph (50 knots), and/or hail at least one inch in diameter.

Special Flood Hazard Areas

Areas where the National Flood Insurance Program’s floodplain management regulations must be enforced and areas where the mandatory purchase of flood insurance applies. 

Sleet or freezing rain

Pellets of ice composed of frozen or mostly frozen raindrops or refrozen partially melted snowflakes.

State Hazard Mitigation Officer 

Individual responsible for developing and maintaining the state’s disaster-specific hazard mitigation plans.

Stormwater management BMPs

Stormwater management Best Management Practices are implemented at the local level to control the quantity and quality of runoff from land development and is most effective by managing site-specific techniques close to the source.

Stream buffers and setbacks

A vegetated area near a stream which helps shade and partially protect a stream from the impact of adjacent land uses with a key role in increasing water quality.

Subarea plan

Area-specific plans that supplement a jurisdiction-wide comprehensive plan. 

Subdivision

The division of land into pieces that are sold or otherwise developed, usually via a plat.

Subsidence

The gradual caving in or sinking of an area of land.

Thunderstorm

The presence of lightning and its resulting thunder usually accompanied by strong winds, heavy rain, and hail, or sometimes no precipitation at all.  

Tornado

A localized, violently destructive windstorm occurring over land. 

Transfer of development rights

Program that allows landowners to sell development rights from their land to a developer or other interested party who can then use these rights to increase the density of development at another designated location.

Use-specific standards

Requirements that are applied to individual use types regardless of the zoning district in which they are located.

Wildfire

Unplanned, unwanted wildland fire, including unauthorized human-caused fires, escaped wildland fire use events, escaped prescribed fire projects, and all other wildland fires where the objective is to put the fire out.

Wildland fire

Wildland fire occurs when vegetation, or “fuel,” such as grass, leaf litter, trees, or shrubs, is exposed to an ignition source and the conditions for combustion are met, resulting in fire growth and spread through adjacent vegetation.

Wildland-urban interface (WUI)

A fire burning situation that has transitioned from natural areas on vegetation to a combination of vegetation and the built environment.

Wind erosion

Wind is responsible for land removal, movement, and deposition and most commonly occurs from exposed areas such as fields, tailings, and desert areas. 

WUI Code

Codes that are specifically designed to mitigate the risks from wildfire to life and property. WUI codes provide a set of wildfire mitigation development standards, including structure density and location, building materials and construction, vegetation management, emergency vehicle access, water supply, and fire protection.