King County GIS Center
King Street Center
201 S. Jackson St.
Suite 706
Seattle, WA 98104

+ 47.59909 N
- 122.33136 W

+ 47°  35' 56.72"
- 122° 19' 52.90"


Landslide Hazards along River Corridors - Rock fall potential

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image


Subject category: enviro
Title: Landslide Hazards along River Corridors - Rock fall potential
Feature Count: 150
Feature Type: Polygon
Abstract: Rock fall is a type of landslide that occurs in bedrock where single or multiple rocks are dislodged and fall from steep cliff faces. In a typical alpine setting, cliffs are located on the upper slopes of a mountain with a talus below, extending to the base of the mountain. The talus is composed of rocks that have fallen from the cliff face and accumulate below the cliff. The talus marks the limit of most rock fall from the cliff, but a few boulders that fall from the cliff travel beyond the toe of the talus. It is these outliers that can pose a hazard to adjacent development (see figure "b" below). Rock fall can be triggered by earthquakes, freeze-thaw cycles, or severe weather. Tumbling boulders falling from a cliff face are fast moving and can level virtually anything in their path.
Purpose: Suitable for general reference and analyses. Identifies only rock fall potential along the river corridor within the study limits in King County.
Status: Complete
Updated: None planned
Time period of content: (single date,as YYYYMMDD):: 20151230
Time period of content: (date range, as YYYYMMDD):: -
Spatial reference: WA State Plane North
FGDC Documentation: Classic or FAQ
Open Data Availability: Yes
Place Keywords: Pacific NW, King County, WA, Washington state,
Theme Keywords: enviro, Pacific NW, King County WA, Washington state, landslide, slide, mass movement, landslide hazard mapping, debris slides, shallow landslides, shallow landsliding, debris sliding,
Lineage: Not available
Supplemental Information: The CONEFALL software program was used to implements this approach in a GIS environment to map areas where rock fall could propagate downslope from a source. As a starting point for the CONEFALL program, cliff-faces were identified to delineate the line representing the base-of-cliff/top-of-talus. Within the study limits, these lines were mapped based on professional judgement using a variety of tools in a GIS environment including vertical orthophotography, oblique photography, and slope mapping. Slopes inclined at more than 200 percent were especially identified.


Maintained by:
King County King County Dept of Natural Resources and Parks, Water and Lands Resource Division
Primary: Ken Rauscher, GIS Analyst, 206-477-4414
(How to e-mail a County contact)
Secondary: KCGIS Center; This mailbox is monitored during business hours.

Attribute Information

_LiDAR_Sour_Source LiDAR imagery and date imagery data sent to Author
KC GIS 2015
_MapDate_Date Author completed mapping
_MapMethod_Method to map rock fall potential
_MapBy_Author of mapped shapes


Access: Access Constraint: Data is not available on GIS Data Portal, it may be available via a custom data request

Use: Use Constraint: King County data are made available with the understanding that they shall be used exclusively by the obtainer or his/her authorized agents. Digital products may not be reproduced or redistributed in any form or by any means without the express written authorization of King County.