BC Coroners Service (BCCS) are using a complex scientific model to crack the mystery of the Salish Sea’s floating feet.
1887 was the first recorded find of a floating stump of a foot, at Vancouver’s so named Leg-in-Boot square, and over the last 12 years 21 feet have washed ashore in Washington State and western B.C.
Theories have ranged from Asian tsunami victims and plane crashes, to a serial killer and mafia hits, but the authorities now think suicides and accidents are more likely causes.
The Special Investigations Unit of BCCS has sought help from a UBC professor, in the Earth, Ocean and Atmospheric Sciences department, who has created a finely tuned computer system called the SalishSeaCast model.
“Susan Allen and her team have constructed a model which records and predicts the tidal surface of the straits; naturally, our team wanted to use that to try and predict, for example, where feet may have come from and how they travel. So Susan Allen’s team was able to send us tidal strength and direction data sets from times just before feet have been discovered to try and get an inkling where they may have come from,” says Andy Watson, Communications Manager for BCCS.
Allen’s model is a real-time research and casting system for the Salish Sea, constructed in collaboration with a number of other scientific and government partners. It is run every day and is so accurate, it has been used to track migrating salmon, predict oil spill movement and by ferries to navigate more safely.
“Finding out how the strait works is infinitely fascinating to me,” says Allen.
Her model uses 14,400,000 box shaped instruments half a kilometre by half a kilometre in size, to track the way the ocean moves. Using fluid dynamic equations for each box, her team is able to calculate the myriad contributing forces, as well as taking other factors into consideration, such as the outflow of 150 different rivers.
As a result, Allen’s group can track and predict the currents, sea temperature, water salinity and storm surges in the strait of Georgia. There is also biological modelling that predicts phytoplankton proliferation and soon there will be an ocean acidification component.
“We have an awful lot of boxes [to analyze] but computers are good at that,” she says wryly.
These computers are some of the most powerful in the country and are run by organizations such as Ocean Networks Canada, Compute Canada, Institute of Ocean Sciences and Environment and Climate Change Canada.
BC Coroners Service contacted Allen specifically to help their investigations into the floating feet, and corpses that originated in Vancouver but washed ashore on Gulf Islands.
“Of course, the tides are unpredictable and ever-changing based on time throughout the day. We know when a particular foot was discovered, for example, but we have no idea when it actually washed up on shore we only know when it was reported to us. However, the data is certainly useful as it gives us a general indication on direction of tidal flow within the area and where remains that might be floating on the surface of the water may go to or come from,” says Watson.
Allen says that she first met the special investigations team this fall and they asked about three specific dates. She is glad her model is being used widely.
“It’s wonderful to know it’s being used in the community. I think it will continue to be used for a bunch of applications and in ways I haven’t even thought of.”
BC Coroners say they will continue to use all tools at their disposal to help their investigations.