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Sea Level Rise and Storm Surges on the B.C. Coast

Sea level is projected to rise approximately 1 metre over the next century. On British Columbia’s coast, sea level change is influenced by both global and local effects.

Sea Level Rise in B.C.

Global sea level is affected by melting of glaciers and ice caps, and warming (thermal expansion) of the upper ocean.  Locally, sea level rise is also affected by vertical movements of the land (tectonic movements, rebound and subsidence).

Estimates of mean sea level rise by 2100 for the B.C. coast range from 80 cm at Nanaimo to 120 cm in the Fraser Delta. Potential impacts of sea level rise in British Columbia include:

  • More frequent and extreme high water levels in coastal areas
  • Increased erosion and flooding
  • Increased risk to coastal infrastructure, as well as increased maintenance and repair costs
  • Loss of property due to erosion
  • Loss of habitat and reduced biodiversity
  • Saltwater intrusion into coastal aquifers
  • Loss of cultural and historical sites

Adapting to Sea Level Rise

To avoid losses from these current and future risks, we will need to plan for, and adapt to the impacts of sea level rise and climate change. Adaptation will involve incorporating sea level rise projections into coastal management practices and planning, both now and in the future. 

All levels of government play a crucial role in working with stakeholders to mitigate and adapt to a changing climate and rising sea level. The B.C. Government supports research, outreach and action on sea level rise in British Columbia.

  • The report Evaluation of B.C. Flood Policy for Coastal Areas in a Changing Climate examines whether current provincial policies and programs support or hinder adaptive decision making, and suggests measures that would facilitate adaptive action along B.C. coasts.
  • The Sea Level Rise Adaptation Primer (PDF/5.8MB) is a resource for local governments and land management authorities, providing information on a range of tools that can be used as part of a sea level rise adaptation strategy.
  • The B.C. Government has completed a series of technical studies to assist practitioners in incorporating sea level rise into coastal flood plain mapping, sea dike design and land use planning.  These reports are intended to inform planning and management decisions in coastal areas.
  • The Juan-de-Fuca Storm Surge Project is a partnership between the B.C. Ministry of Environment and Canada's Department of Fisheries and Oceans. The project includes an operational ocean model to predict storm surge activity along the British Columbia coastline.
  • The King Tide Photo Initiative is a public outreach and engagement campaign that invites people to observe today's high water events (high tide/storm surge events) and imagine the future of B.C.'s coastline with sea level rise.
  • Sea level rise projections for tide gauge and GPS stations on the BC coast (PDF/100KB). These projections are based on a global sea level rise of 1m by the year 2100. This is the level currently recommended for planning purposes.

Click to open Google Earth view of SLR along B.C.'s Coast

Storm Surges along the B.C. Coast

Winter storms on the west coast of Canada bring high water and waves to coastal regions. When combined with high tides (especially King Tides) these conditions can cause flooding and erosion.

The British columbia Ministry of Environment has partnered with Canada's Department of Fisheries and Oceans to develop a storm surge prediction system. The system uses an operational ocean model already in use at the Institute of Ocean Sciences in Sidney, B.C., and weather forecasts from Environment Canada and NOAA to calculate the difference between the predicted astronomical tide and actual sea surface height.

Storm surge forecasts are updated daily and are used by emergency management professionals on B.C.’s coast to prepare for and mitigate the risks of damaging storm and high tide events. Improving information and awareness about storm surges is also an important component of preparing B.C. for sea level rise.

Storm Surge Forecast System Information Portal

A new BC Storm Surge Forecast System portal was launched in 2011 to provide quick and easy access to storm surge model outputs and information. The website provides links to the animated map and charts generated by the Pacific Ocean Model driven by a 7-day weather forecast from NOAA and a 6-day forecast from Environment Canada. Daily storm surge forecast bulletins are also availabe for Point Atkinson, Victoria and Campbell River and are automatically updated each morning. Other information available through the portal includes the seasonal storm surge almanac, reports, photos and presentations. Notifications about storm surges and model updates can also be received by following @SurgeBC on Twitter.

Daily Forecast Bulletins

Victoria High Water Bulletin (6-day forecast):

Point Atikinson High Water Bulletin (6-day forecast):

Campbell River High Water Bulletin (7-day forecast):

Almanac

The Almanac provides a summary of the marine environment of southern British Columbia as it relates to the upcoming season:

Model - Animated Map

The storm surge model predicts storm movement and the resulting sea surface heights (SSHs) for the coming week.

The map below (on the left) shows the Northeast Pacific Ocean (colours) and the West Coast of North America (white). The black dots correspond to American tidal stations listed in the Chart (on the right) - from Kodiak, Alaska to Crescent City, California. (Neah Bay is located on the Olympic Penninsula in Washington state, approximately 90km west of Victoria; while Cherry Point is located approximately 30km southeast of Vancouver).

Sea Surface Height (SSH) is indicated by colour. SSH can be negative (purple), zero (blue) or positive (green, yellow, red). SSH measures how much the water level is displaced, independent of the tide. In other words, if a 3m high tide coincides with a storm surge with a +20cm SSH, then the water level will be at 3.2m. On the other hand, if the storm surge has a negative SSH, the high tide will be reduced; or alternatively, if a storm surge with a high SSH (e.g. +60cm, red) reaches shore during low tide, it may go relatively unnoticed.

Storm surges are therefore the most pronounced -- and can cause the most damage -- when they coincide with high tides. The forecasting of these events is posted for Victoria and Point Atkinson (West Vancouver) in the Daily Reports above.

The Chart on the right plots (for each tidal station) the recently observed SSH in black and the predicted SSH for the following week in red.

To access the Storm Surge Model, click on the screenshot below.

Juan-de-Fuca Storm Surge Model

Model - Instructions

The buttons below the map are used to control the model:

Start Go to frame #1
End Go to the last frame
-1 Go one frame ahead
+1 Go one frame behind
> Play forward
< Play backward
[] Stop
play once plays the animation once from start to end
loop repeat animation in continuous loop
swing plays the animation forward then backward
speed +/- controls the frame rate (up/down)