Tsunami Information Page
On this page you will find the following:
- WHAT is a tsunami?
- WHAT is the difference between a local and distant tsunami?
- HOW will I be notified?
- WHAT do the different Tsunami Alerts mean?
- MORE resources
A tsunami is a natural hazard consisting of a series of long, surge-like waves generated when a large volume of ocean water is rapidly displaced. Most tsunamis are caused by major subduction zone earthquakes, where there is significant displacement of the ocean floor. Tsunami waves differ from ordinary coastal waves in that the entire column of water from the ocean floor to the surface is affected. Tsunami waves contain considerable energy; they can travel further inland compared to ordinary coastal waves. A tsunami may not look like a wave at all, but will have very strong currents under its surface.
A tsunami is a series of waves. The first wave to arrive at the coast is often not the largest, and each wave may be separated by up to an hour or more. Waves may continue for up to twelve hours; please stay away from the shore until local officials tell you it is safe to return.
Tsunamis are a challenging hazard to respond to. The arrival time of the wave generated far out at sea can be predicted fairly accurately, however, the intensity of the wave when it reaches shore is more difficult to predict, particularly in real time during an event.
On the west coast of North America, tsunamis are categorized as local or distant, depending on the location of the earthquake and the size of the area affected.
A local tsunami is generated from a source within 1000 kms or less than 1 hour tsunami travel time from its source to the area impacted. For Tofino, it could be minutes before the tsunami reaches our shoreline. Damage and inundation from a local tsunami is typically widespread. Major earthquakes are often a precursor to a local tsunami. The most dangerous tsunami threat to the BC coast will follow a major, "megathrust" earthquake. Such an earthquake will cause ground shaking lasting three to five minutes. The shaking will be so strong it will be difficult to stand in many places.
Local Tsunami Notification
How will I know if a tsunami is coming?
For a Local Tsunami STRONG SHAKING IS THE WARNING -
Do NOT rely on official notices for warning to evacuate.
While a distant tsunami will likely allow time for an official tsunami message to be given, a local tsunami can reach the shoreline in minutes and may NOT allow for an official warning to take place.
In this case natural signs may be your only warnings to take action, such as:
- the strong shaking from the earthquake
- a receding ocean, or
- a loud roar-like sound,
Local Tsunami Evacuation
If you are near the coast and feel a major earthquake making it difficult to stand, you must "Drop, Cover, and Hold On", and then evacuate to higher ground immediately.
The first wave generated from an earthquake could be in the Tofino area within 15-20 minutes. The first wave to arrive may not be the largest. Get your Grab-and-Go bag and Emergency Plan if easily accessible and evacuate immediately on foot or by bicycle to an area outside of the tsunami hazard areas (see map, click image to enlarge).
Do not return to low-lying areas to gather your belongings. Emergency Officials will let you know when it is safe to return home.
A distant tsunami is generated from further than 1000 kms away, or more than 3 hours travel time from the tsunamis source to the area impacted. Damage from a distant tsunami is typically limited to low-lying coastal areas. Response to a distant tsunami is significantly different than to a local tsunami. Typically, there is more time for an official warning and evacuation to safety. More evacuation infrastructure and support will be readily available during this type of event.
Distant Tsunami Notification
The District of Tofino receives distant tsunami notification via Emergency Management BC and the National Tsunami Warning Center (NTWC). If a tsunami threat is identified, Emergency Management BC will activate the Provincial Emergency Notification System (PENS), which notifies the District of Tofino through email, phone call, social media, Short Messaging System (SMS), Environment Canada EC Alert, and Channel 16 marine radio with information on alert levels for the province’s five tsunami zones. The District of Tofino also receives tsunami alerts directly from the NTWC via SMS and NOAA weather radio.
The District of Tofino follows best practice by having several different notification systems in place within our community in order to achieve maximum warning to the public. Best practice recognizes that in most cases, notification systems activated in a real event will have some level of malfunction or failure despite rigorous pre-event testing.
During a distant tsunami event, the District of Tofino will make every effort to broadcast official tsunami alerts and updates by email, telephone, text message, social media (twitter and Facebook), outdoor sirens, radio and/or door-to-door contact if possible.
Distant Tsunami Evacuation
In the event of a Distant Tsunami Warning, a full evacuation of the tsunami hazard areas identified on the District evacuation map above is suggested (all areas below 20m). The Community Hall will be activated as the Emergency Reception Centre. The reception centre can easily become overwhelmed and is not capable of absorbing the entire community. The District encourages those who live at a safe elevation to remain at home. And asks that those who have friends and family they can stay with outside of the tsunami hazard area to do so.
Please bring your Grab-and-Go bags and any specific items you may need (medications, mobility aids, etc.) with you.
Tsunami sirens are designed to provide a rapid alert and are currently one of the most effective mass notification means of alerting outdoor populations. They are most useful when there is a concentrated outdoor population within the sound-range of the sirens or where there is no other means of notification, such as beach locations.
Tsunami Siren Accoustic Map
Sirens are intended to be used to alert outdoor populations to the potential threat of a distant tsunami, when there is typically time for an official warning and evacuation.
They are NOT intended to be used to notify indoor populations. Also, there may not be time to activate the sirens in the event of a local tsunami.
Tsunami’s can happen anytime. If a tsunami warning is received by the Distirict of Tofino during the middle of the night we will used every notification method at our disposal to alert you, including activating the sirens.
Tsunami Sirens Test
The District of Tofino tests the tsunami sirens silently every day. We audibly test the sirens on the first Friday of each month. The test siren will state that it is just a test and play the "Westminster Chime", which is the international "all clear tone" in emergency warning systems.
To hear the "Westminster Chime" click here
Tsunami Emergency Siren
During a real event, a loud wailing tone will be played over the siren and a message stating the level of alert and instructions will be broadcast.
To hear the "Emergency Siren" click here
During an emergency event, the District of Tofino will make every effort to broadcast official tsunami alerts and information by email, telephone, and text message via the Voyent Alert! system, as well as by social media, outdoor sirens, radio and/or door-to-door contact if possible.
The District of Tofino uses our official social media accounts to communicate during emergency events. For accurate, up to date information, click:
Tsunami Warning: A Warning is the highest level of tsunami alert. Warnings are issued due to the imminent threat of a tsunami from a large undersea earthquake, or following confirmation that a potentially destructive tsunami is underway. They may initially be based only on seismic information as a means of providing the earliest possible alert. Warnings advise that appropriate actions be taken in response to the tsunami threat. Such actions could include the evacuation of low-lying coastal areas and the movement of boats and ships out of harbours to deep waters. Warnings are typically updated hourly, or as conditions warrant, to continue, expand, restrict or end the Warning.
Tsunami Advisory: An Advisory is the second highest level of tsunami alert. Advisories are issued due to the threat of a tsunami that has the potential to produce strong currents dangerous to those in or near the water. Significant inundation is not expected for areas under an Advisory, but coastal zones may be at risk due to strong currents. Appropriate actions by emergency management personnel may include closing beaches and evacuating harbours and marinas. Additionally, local officials may opt to move boats out of harbours to deep waters, if there is time to safely do so.
Tsunami Watch: A Watch is the third highest level of tsunami alert. Watches are an advance alert that, based on an analysis of the event, may be cancelled or upgraded to a Warning or Advisory prior to impact. There is a potential threat to a zone contained in a Watch but communities have time to prepare. Watches are normally based on seismic information, without confirmation that a destructive tsunami is underway. Emergency management personnel and coastal residents should prepare to take action in case the Watch is upgraded.
Information Statement: An Information Statement informs that an earthquake has occurred and that there is no threat of a destructive tsunami affecting Coastal B.C. These statements are used to prevent unnecessary evacuations when an earthquake felt in coastal areas has a magnitude that may raise concern about a possible tsunami.
GUIDES AND RESOURCES