Giant Floating Island Appears on B.C. Reservoir—Then Disappears
- BoatBlurb Contributor
- 12 minutes ago
- 4 min read
A tree-covered island the size of a Walmart was confirmed by satellite imagery drifting across Williston Reservoir in British Columbia last week. B.C. Hydro still doesn’t know where it came from or where it went.
An entire chunk of forest appears to have broken free and gone missing on a mad-made British Columbia reservoir.
A massive, tree-covered floating landmass was spotted on Williston Lake in northern B.C. earlier this summer, only to disappear from satellite imagery a few weeks later.
The seemingly newly-formed island was estimated to be approximately 70 metres wide by 140 metres long, covering about 9,800 square metres, or 2.5 acres. The surface area is roughly the equivalent of a Walmart.
Despite it seeming impossible for such a large object to appear out of the blue, the island disappeared shortly after it was first spotted. No one knows where it is now, including the locals who spotted it or B.C Hydro who's responsible for the hydroelectric dam.
Local boater Rocky Avery received photos and video of the island and shared them to Facebook, where they quickly went viral.
B.C. Hydro, the Crown corporation responsible for providing power to the province and maintaining the Williston Reservoir hydroelectric dam, was initially suspicious of Avery's posts, suspecting that maybe some realistic AI-generated images were at play.
“It’s certainly something we’ve not heard of before,” B.C. Hydro spokesperson Bob Gammer told CBC News.
Despite the size of the new island, Gammer noted that given there were only a couple social media posts to work from, his team was unable to find it. They could only confirm its existence using satellite imagery.
Images from July 21 showed the floating mass in the main body of the reservoir, west of Finlay Bay and approximately 100 kilometres west of the W.A.C. Bennett Dam. By August 5, however, the island was no longer visible.
“We’ve been taking more updated snapshots and we can’t see the object anymore. So it’s disappeared now,” Gammer told CBC News.
But, that doesn’t mean the floating forest sank.
“It doesn’t mean it’s gone to the bottom of the reservoir,” Gammer said. “It may have returned to a more sheltered area along the shoreline.”
So, in today's high-tech age where everyone has a camera phone and nothing stays hidden, where could it be?
B.C. Hydro has a theory, although the company stresses that it cannot pinpoint the island’s exact origin.
The most likely explanation involves a combination of driftwood, vegetation, and unusually high water levels.
Over a period of years, driftwood and other organic material can accumulate along a reservoir’s shoreline. As that material decomposes, vegetation can establish itself on top, with interwoven roots helping to hold the mass together. In essence, it can turn a pile of driftwood and debris into a living mass that isn't entirely connected to the shoreline.
Eventually, enough of the material accumulates that it becomes capable of supporting vegetation and trees.
Couple that with high water levels, and you have the potential for an entirely new island to break free from its delicate connection to the mainland, with wind and currents pushing it into open water.
Williston Reservoir has experienced unusually high water levels in 2026 thanks to a heavy winter snowpack and a summer full of rain. B.C. The lake was created in 1968 by the building of the W. A. C. Bennett Dam on the Peace River.
“We haven’t had a full reservoir in 14 years,” Gammer said. “We can’t pinpoint the origin of this floating island [but that’s] one explanation that seems reasonable.”
While it seems impossible to lose an entire island within an enclosed space, Williston Reservoir is so large it's not as improbable as you might think. The reservoir covers approximately 1,761 square kilometres and is the seventh-largest reservoir in the world by volume. The newly formed island spans roughly 10,000 square metres, meaning it covered just 0.00057% of the reservoir's surface area. The 2.5 acre island is adrift within a 618,000 acre waterway.
B.C. Hydro says it's simply not practical to continuously patrol the entire reservoir by boat and relies partly on public reports to identify hazards.
Ironically, B.C. Hydro has operated a surface debris-clearing program on the reservoir since 1968, but no one anticipated, or was aware, of such a large mass developing along its shoreline. The utility regularly has to caution boaters that tree limbs, stumps, and other debris may sit just below the surface throughout the waterway. Sudden winds, which are common over the large expanse, also produce waves exceeding two metres, which quickly move debris across open water.
Avery told CBC News that debris can be particularly difficult to spot once the water becomes choppy.
“When it’s calm, it’s fine. You can usually see them, but you get a little bit of choppy waves, and it’s really hard to see them until you’re right on top,” he said.
“Some are full-size trees and it’ll do a lot of damage to your boat. So you got to be super careful.”
So, given the reservoir's propensity for creating and moving debris, will the newly formed island reappear?
Quite possibly.
B.C. Hydro has not determined if the floating island sank, broke apart, or simply drifted into a sheltered area where it's currently camouflaged by the terrain.
The utility says it it is continuing to monitor for the formation and has asked the public to report any sightings.
For now, the mysterious island remains somewhere on Williston Reservoir—and boaters are keen to find it.
At least from a safe distance and at a slow speed.
You can see Avery's footage of the floating island below:
Comments