DOGAMI Open-File Report Series

[Go back] | Publications Center | DOGAMI Home

Publication Preview

Open-File Report O-21-01, History of the Oregon Landslide Warning System 1997–2018 and recommendations for improvements,
by William J. Burns and Jon J. Franczyk; 21 p. report, 8 appendix documents.

What's in this report?
Oregon implemented a landslide warning system following the storm events and landslides of 1996-1997. The purpose of this report is to provide background and context for the landslide warning system, to examine the effectiveness of the system since its implementation, and to offer recommendations for improvement and strategies for increasing effectiveness.

Report download:

REPORT INTRODUCTION

The combination of geology, topographic relief, and wet climate make the Pacific Northwest particularly susceptible to precipitation-induced landslides. In Oregon, especially in the mountainous western part of the state, landslides are a common natural hazard. With increasing population and development throughout the state more people and infrastructure are exposed to landslide risk. The purpose of this report is to provide background and context for current landslide warning system in Oregon, analyze the effectiveness of the system since its implementation, offer recommendations for improvement, and provide some implementation strategies. A more effective landslide warning system will benefit all Oregonians.

The particularly destructive 1996-1997 winter storm seasons included three storm events that resulted in landslides throughout the state. Each event impacted a different area and received a federal “major disaster” declaration. The storms were a record-breaking four-day rain event (February 1996), a one-day rain event (November 1996), and a series of storms that moved up the Oregon coast over weeks (December 1996 through January 1997) (Hofmeister, 2000). In the 1996-1997 storms, several debris flows (dangerous, rapidly moving landslides [Hofmeister and others, 2002]) resulted in five fatalities and damage to many homes, roads, and bridges (DOGAMI and others, 2000).

In response to the 1996-1997 landslide events, Oregon developed a landslide warning system—the Emergency Warning System for Debris Flows and Torrents in Western Oregon—that was used for the first time during the winter of 1997-1998. The purpose of the warning system was to “inform local residents, other landowners, drivers, road managers, and emergency planners of situations when and where debris flows/torrents are expected” (appendix document A1).

TIMELINE AND APPENDIX DOCUMENTS

Timeline Action/Publication Appendix Item
1997 “Governor Releases Recommendations to Address Dangerous Debris Avalanches” [Debris Avalanche Action Plan [news release] (Oregon Governor’s Office, March 4, 1997) A1
1997 Interagency Hazard Mitigation Team (IHMT) created (IHMT website: https://www.oregon.gov/oem/Councils-and-Committees/Pages/IHMT.aspx)
1998 “Landslides in Oregon: Protect Yourself and Your Property” [brochure] (DOGAMI, ODF, Oregon Department of Consumer and Business Services, Oregon OEM, 1997) A2
1998 “Joint Interim Task Force on Landslides and Public Safety, Report to the 70th Legislative Assembly, 1998” (https://digital.osl.state.or.us/islandora/object/osl%3A83625), task force established by Senate Bill 1211 (1997)  A3
1998 Oregon Landslide Warning System charter (1998) A4
1999 Oregon Senate Bill 12 (SB-12, https://www.oregonlegislature.gov/bills_laws/archivebills/1999_sb0012.en.html) in 1999 established a new mandate directing state and local governments to protect people from “rapidly moving” landslides or debris flows. SB-12 was codified as ORS 195.250-195.275, ORS 257.630-527.710.
2000 “Report to the Seventy-first Legislative Assembly on the Implementation of 1999 Senate Bill 12 Relating to Public Safety and Rapidly Moving Landslides” (DOGAMI and others, 2000; https://digital.osl.state.or.us/islandora/object/osl:24654) A5
2001 “Forestry, Landslides and Public Safety” Landslides and Public Safety Project Team, 2001, Forestry, landslides and public safety; an issue paper prepared for the Oregon Board of Forestry (https://www.oregon.gov/ODF/Documents/WorkingForests/landslidespublicsafety.pdf)
2005 Emergency Warning System for Debris Flows in Western Oregon (charter update 12-19-2005) A6
2007 Emergency Warning System Procedures for Debris Flows in Western Oregon (charter update 12-03-2007) (also at https://www.oregongeology.org/Landslide/ODFDebrisFlowWarningTechOverview.pdf) A7
2018 Communication Process – Landslide/Debris Flow Alerts as of 2018 A8