How long would it take to outwalk a tsunami?
The 2011 Japanese earthquake and tsunami proved that walking to higher ground can save your life when a killer wave is headed to shore.
But every minute counts.
To better educate the public on how long it would take to get out of a tidal wave’s deadly reach, the state Department of Natural Resources has created a series of highly detailed maps for Bellingham, Aberdeen, Hoquiam, Cosmopolis, Anacortes and Port Angeles.
The maps illustrate how many minutes it would take to walk to a safe zone from various sections of those cities and towns. Parts of all of those communities are in the projected inundation zone of a tsunami generated by an earthquake on the Cascadia fault, about 50 miles off the Washington coast.
“If you feel an earthquake, that’s your warning and you should evacuate and get to high ground immediately,” said Corina Forson, chief hazards geologist.
However, Forson said, a tsunami can arrive without an earthquake warning. Waves from the 2011 Japanese quake struck California and Oregon several hours after the quake, which wasn’t felt in North America.
The evacuation times are based on a slow walking pace easily maintained by the average adult, according to Daniel Eungard, a tsunami scientist. It equates to about 2.5 miles per hour.
“If you can cross through a crosswalk before the (red) hand comes up ... then you are walking faster than this pace,” he said.
The good news for Bellingham, according to the maps, is that even at this pace, it shouldn’t be difficult to out-walk a tsunami, which should take more than two hours to arrive, according to the DNR models.
With that much time, even people at the farthest reaches of the city at the time of the quake should have enough time to stroll to safety by a factor of three or four.
Even if you were out on the tip of Pier G at Squalicum Harbor — the harbor’s farthest from shore and longest — when the Cascadia quake struck, the DNR estimates it would take you only 30 minutes to walk to higher ground that should remain untouched by a tsunami.
Zuanich Point Park would take a 15- to 20-minute walk to safety, while the Bellwether Hotel is 10 to 15 minutes from higher ground.
The walk to safety from the Bellingham Shipping Terminal would be approximately 15 to 25 minutes long, according to the map, while a tsunami can be avoided within just five minutes from Boulevard Park.
In Fairhaven, the longest walking evacuation is the 15 minutes it would take from the Bellingham Ferry Terminal.
Other parts of Whatcom County that might be affected by a potential tsunami, including the Lummi peninsula, Nooksack River outlet and Blaine, were not included in the maps the DNR released.
A different approach
John Gargett, the Whatcom County Sheriff’s Office’s Deputy Director of the Division of Emergency Management, recently returned from a trip to New Zealand, where he said he studied their tsunami program.
“They took a different approach,” Gargett told The Bellingham Herald. “They didn’t specify the exact route you should take and how long it would take you, but instead gave a general direction. They did contours of elevation to show where you need to go. That’s probably the way we’re going to go in Whatcom County.”
For example, Gargett said, if the tsunami siren sounds in Birch Bay, you can’t predict what damage was done by the earthquake to the roads that could get you to higher ground. Perhaps Harborview Road or Birch Bay Drive are no longer walkable, he said, eliminating that route as an option.
“We want to get everybody to go in a certain direction — up,” Gargett said, “and here are some areas you would probably be able to get to where you should be high enough.”
While Gargett said the maps can be useful tools, he recommends that looking at them is only the start or your family’s emergency plan.
“What I advise residents of Whatcom County to do is to take the time to think about what you would do if you hear a report that a tsunami is on the way,” Gargett said. “How would you walk or drive to an area that is at least 40 feet in elevation above the house or business you’re in. Know your area. Then I would go out and do it so you know exactly how long it could take you.”
Safest method to evacuate from a tsunami
Why not just drive, rather that walking, you may ask.
In a major earthquake, utility poles might fall, ground could liquefy, roads could fissure, bridges and buildings might collapse. Walking may be your only way to safety.
The maps also show main and secondary evacuation routes.
The evacuation time estimates are based on LIDAR imaging, surfaces and obstacles.
“This is all taken into account in the modeling process,” Eungard said. He suggested making a practice run, especially if you have children or a disability.
The time estimates begin the moment the ground begins to shake, Forson said.
“If this is a Cascadia subduction zone earthquake, shaking could last five minutes,” she said.