Tsunamis

A tsunami is a natural hazard consisting of a series of unusually large waves formed by a large-scale disturbance of water bodies. One of the primary causes of tsunamis is an earthquake, but tsunamis may also be triggered by landslides, volcanoes or explosions.

If you are near the ocean and feel a major earthquake, or if the motion makes it hard to stand, get to higher ground immediately - do not wait for an official warning. The shaking is your warning.

Local government officials may not have enough time to issue a warning to residents in the event of tsunami created by a near-shore earthquake. Roads may be congested and communications systems compromised.

Generally, 4 metres or 13 feet elevation above sea level is considered a safe distance from the ocean on Southern Vancouver Island. You do not need to go to the highest point in the Region.

Tsunami Preparedness

The probability that a tsunami will do damage along British Columbia's coast is small, but very real. If you live in a coastal area of the Capital Region, you and your family need to know what to do in the event of a tsunami and be prepared to respond.

Stay Alert for Natural Warnings of Tsunami

Tsunami signs to watch for:

  • A sudden rise or fall of ocean level
  • A loud roaring noise coming from the ocean
  • Ground shaking

Know the Natural Warning Signs

The probability that a tsunami will do damage along British Columbia's coast is small, but very real. If you live in a coastal area of the capital region, you and your family need to know what to do in the event of a tsunami and be prepared to respond.

Stay alert for natural warnings of a tsunami.

Tsunami signs to watch for:

  • A sudden rise or fall of ocean level
  • A loud roaring noise coming from the ocean
  • Ground shaking

Know your Zone

Tsunami Hazard Line - Capital Region

Here in the Capital Region, you may live, work or play in an area at risk of a tsunami. Visit the Tsunami Hazard Line Map to learn about tsunami hazard mapping in the region.

British Columbia's Tsunami Notification Zones

BC's coastal communities are divided into five tsunami notification zones. Each zone includes all islands and inlets within it.

Here in the Capital Region, you may find yourself in three of the five notification zones:

  • Zone C: Outer west coast of Vancouver Island including Port Renfrew
  • Zone D: Juan de Fuca Strait from Jordan River to Greater Victoria including the Saanich Peninsula
  • Zone E: Strait of Georgia including the Gulf Islands.

When tsunami warnings, watches or advisories are issued, may make reference to these zones.

Tsunami Warnings, Advisories and Watches

The Tsunami Warning System is an international program to detect tsunamis and provide notification and warnings to communities around the world.

Here in the capital region, there are two types of tsunamis, local and distant.

  1. Local Tsunami: will be associated with a "felt" earthquake.
  2. Distant Tsunami: will happen far away (like Japan or Alaska) and may not be felt.

If a Tsunami Warning, Advisory or Watch is issued for your area, monitor local media and follow the instructions of local emergency officials. These alerts may be updated, adjusted geographically, downgraded, or cancelled; and are initially normally based only on seismic information to provide the earliest possible alert.

Government officials may issue one of the following alerts:

Warning

  • Threat: Flood wave possible
  • Action: Full evacuation suggested

This is issued when a potential tsunami with significant widespread inundation is imminent or expected. Warnings:

  • alert the public that widespread, dangerous coastal flooding and powerful currents is possible and may continue for several hours
  • alert emergency management officials to take actions like the evacuation of low-lying coastal areas, and the repositioning of ships to deep waters when there is time to safely do so

In the event of an Immediate Tsunami Threat:

  • Move to higher ground, and go on foot if possible.
  • Follow the instructions of all emergency officials for your safety and the safety of those around you.

All areas of the coastline will not be impacted equally. Within very short distances, the effects of a tsunami may vary considerably and there could be dramatic differences in wave height and impact.

Advisory

  • Threat: Strong currents likely
  • Action: Stay away from the shore

This is issued due to the threat of a potential tsunami which may produce strong currents or waves dangerous to those in or near the water. Coastal regions historically prone to damage due to strong currents induced by tsunamis are at the greatest risk. Advisories:

  • may continue for several hours after the arrival of the initial wave, but significant widespread inundation is not expected for areas under an advisory
  • may result in local officials closing beaches, evacuating harbours and marinas, and the repositioning of ships to deep waters when there is time to safely do so

Watch:

  • Threat: Danger level not yet known
  • Action: Stay alert for more information

This is issued to alert emergency management officials and the public of an event which may later impact the watch area. Watches indicate emergency management officials and the public should prepare to take action.

During A tsunami

Never go to the coast to watch a tsunami.

Once at higher ground, stay there! Tsunami waves can last several hours and the first wave is not always the largest. Do not go back to tsunami hazard areas until instructed by local government officials.

Boats in Deep Water

If you are in deep water (at least 200 fathoms or 400 metres) when a tsunami warning is issued, stay there. Tsunami waves are small in deep water and probably won’t cause any damage. Stay tuned to your marine radio (Channel 16) for reports when it is safe to return to port.

Boats in Harbour

If you are still in the harbour when a tsunami warning is issued, you may have time to get to deep water. Listen to official estimated tsunami wave arrival times and plan safely. Do not motor your boat to open water if it is too close to the wave arrival time.

Moored Boats

If there is a local tsunami and you are moored in a harbour, abandon your boat immediately. Head for high ground.

Floatplanes

If you are in a floatplane in a harbour, take off as soon as possible. Land safely on a lake or another area not at risk.

More information is available for boaters.

After a Tsunami

If a Tsunami Warning, Advisory or Watch has been issued for your area, monitor local media and follow the instructions of local emergency officials.

Local government officials will tell you when the danger has passed by cancelling the Tsunami Alert.

Tsunami Warnings

If a tsunami warning is issued, head inland or to high ground immediately! Try to do so on foot or bicycle to keep roadways clear for emergency personnel.

A warning may be issued in the form of a siren or through radio and television broadcasts.

If you feel a large and strong earthquake, that is the warning. Don't wait for any other alert and head to higher ground.

Additional Resources

Learn more about Tsunami Hazards in the Capital Region by downloading a Tsunami Hazard Line Map.

Visit PreparedBC to download the Earthquake and Tsunami Guide.

Visit the National Tsunami Warning Center (NTWC) which provides tsunami warnings to California, Oregon, Washington, British Columbia and Alaska.