Formation Descriptions

A: Avalanche -- Boundary of avalanche danger area and flow direction.

AL: Active Landslide -- Boundary of a large scale slope failure involving surficial and bedrock material that has not yet stabilized. Maybe composed of poorly sorted thin to thick, fine to course colluvial and bedrock material on gentle to steep slope

BR: Bedrock -- All other areas of consolidated earth material usually considered to be sound and stable.

BR(US): Bedrock/Unstable Slope -- Bedrock areas that are potentially unstable if distributed; these are poorly consolidated geologic units

DF: Debris Fan -- Boundary of cone shaped stream deposited material. Area subject to recurring flooding and deposition.

EF: Earth Flow -- Boundary of an area of plastic flowage of a mass of earth material.

F: Fault or Fault Zone -- Surface trace of known (documented) plane of rock displacement. Potential for movement exists along these planes during seismic activity. Routt County is in Seismic Zone II.

IL: Inactive Landslide – A slope failure bedrock and/or surficial material consisting of one mass movement type that has reached equilibrium and is stabilized under present condition

LS: Landslide -- Boundary of a large scale slope failure involving surficial and/or bedrock material. Generally consists of one slope failure type, i.e., a rockslide or a landslide.

MF: Mud Flow -- Boundary of a flowing or solidified mass of predominately fine-grained earth material possessing a high degree of fluidity during movement.

NONE: No Hazards Mapped.

PUS: Potentially Unstable Slopes -- Boundary of slopes with geologic conditions present that may lead to unstability when disturbed. Slope failure may be either surficial or deeper seated.

RF: Rockfall -- Boundary of danger zone from falling or rolling rock; landfill and strip mine spoil.

RF/PUS: Rockfall/Potentially Unstable Slopes --

RF/US: Rockfall/Unstable Slopes --

S: Subsidence -- Areas of potential ground subsidence. Surface boundaries of underground mining operations; includes filled in gravel pits, landfill and strip mine spoil.

SD: Surficial Deposits -- Relatively thin, unconsolidated earth material overlying bedrock. These deposits are not a hazard in themselves, but certain types maybe unstable.

SFC: Slope Failure Complex -- Boundary of large areas of failure of surficial and/or bedrock deposits. May consist of different slope failure types, i.e., rockslides, landslides, debris slides, mudflows, and debris avalanches.

UNK: Unknown -- Undeterminable from source map or in unmapped area.

US: Unstable Slopes -- Boundary of slope areas where slow downward movement is in evidence in the form of slump, soil creep, minor earth flow or heavy erosion. More rapid movement possible. May be man induced or natural. Includes both surficial and deeper seated slope failure.

W: High Groundwater Table -- Areas of swamps, sloughs and very near surface groundwater.