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 avalanche deposit

Description | Contacts | Attribute Information | Constraints

Data layer thumbnail image


Subject category: enviro
Title: Landslide Hazards along River Corridors - Rock avalanche deposit
Feature Count: 3
Feature Type: Polygon
Abstract: Rock avalanche is a style of landslide characterized by the simultaneous failure of an entire bedrock hillslope and with the dislodged mass cascading to the valley below. Rock avalanches move at extremely high speeds and are potentially massive in size. They can extend farther from the base of slope and cover a much larger area compared with individual rock fall.
Purpose: Suitable for general reference and analyses. Identifies only rock avalanche deposits along the river corridor within the study limits in King County.
Status: Complete
Updated: None planned
Time period of content: (single date,as YYYYMMDD):: 20160620
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: Rock avalanche deposits were identified within the study limits using USGS geologic maps, review of LiDAR imagery, interpretation of orthophotography, field investigation, and geotechnical reports. The figure below is an example of a rock avalanche deposit mapped in the South Fork Skykomish River valley. Due to the lack of detailed information on significant variables including rock strength, zones of weakness and joint patterns, predictions of future sites of rock avalanches were not feasible.


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

_Mapby_Author of mapped shapes
Beckler Peak
Index Creek
Moon Valley Rd-Mt Si
_Mapdate_Date Author completed mapping
_MapMethod_Method to map deposits
_LiDARSrce_Source LiDAR imagery and date imagery data sent to Author
KC GIS 2016-06


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.