Chronic Hazards

Flooding and erosion are chronic problems along the Oregon coast and these hazards are intensifying in response to both rising sea levels [1] and changing patterns of storminess [2]. Major winter storms are often the drivers for both hazards and research shows that, while generally storms are becoming less frequent, the number of severe storms are in fact increasing [3]. Some regions are particularly susceptible to hotspot erosion due to their geologic setting, e.g., if the underlying lithology is weaker and/ or there is greater exposure to wave erosion. As a result, human infrastructure on the coast becomes increasingly vulnerable and costly to maintain.

Previous studies by the Envisioning Oregon Coastal Futures group in Grays Harbor and Tillamook Counties have demonstrated that management decisions have a greater bearing than different climate change scenarios in shaping our future coastlines, i.e., policy changes matter more than the rate of future climate change. For this reason, the OCF project seeks to help Oregon communities identify policy options that best achieve their resilience objectives, while still prioritizing broader community goals and values.

Chronic hazards modeling does this by evolving the coastal landscape over timescales of decades to centuries, keeping in mind how different policy options will impact how the landscape changes. The models link essential climate processes to erosion and flooding seen on the Oregon Coast. Probabilistic assessments are produced in order to quantify the uncertainty associated with future scenarios. In this way, communities can decide what level of risk they are willing to take on as they plan their future- what would we need to do to prepare for the 50th percentile scenario? What about the 100th percentile (worst case) scenario?

As chronic hazards models evolve the landscape, we expect they will reveal areas in which current Oregon resilience planning fails to meet the needs of all its citizens and puts some groups in more vulnerable positions than others. By exposing these issues we hope to increase the attention that is put into ensuring equitable planning and policy is put into place.

Technical Details on the Chronic Models used in this Study


[1] Sweet, W.V., R.E. Kopp, C.P. Weaver, J. Obeysekera, R.M. Horton, E.R. Thieler, and C. Zervas, 2017: Global and Regional Sea Level Rise Scenarios for the United States. NOAA Technical Report NOS CO-OPS 083. NOAA/NOS Center for Operational Oceanographic Products and Services.

[2] Barnard, P., Hoover, D., Hubbard, D., Snyder, A., Ludka, B., Allan, J., Kaminsky, G., Ruggiero, P., Gallien, T., Gabel, L., Mccandless, D., Weiner, H., Cohn, N., Anderson, D., Serafin, K. (2017). Extreme oceanographic forcing and coastal response due to the 2015–2016 El Niño. Nature Communications. 8. 14365. doi: 10.1038/ncomms14365.

[3] Ruggiero, P., Kratzmann, M.G., Himmelstoss, E.A., Reid, D., Allan, J., Kaminsky, G., 2013. National Assessment of Shoreline Change: Historical Shoreline Change along the Pacific Northwest Coast.

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