A nearly 2.5-acre floating island appeared in late July 2026 on Williston Lake, a vast reservoir in northern British Columbia, Canada.
A month later, with no clear explanation, it was gone.
BC Hydro, the provincial electric utility, confirmed the sighting was genuine and has been keeping watch on the reservoir ever since, in case the island reappears.
It started with a video. A boater crossing the reservoir spotted a tree-covered patch of land drifting by itself in open water roughly 62 miles from the W.A.C. Bennett Dam.
He filmed it and posted the footage online. Within days, the clip had topped 140,000 views.
When word of the sighting reached BC Hydro, even its own technicians initially doubted the footage was genuine. Given how much AI-generated content circulates online these days, their skepticism was understandable.
But satellite images taken on July 21 confirmed the island existed. It measured about 230 feet wide by 460 feet long—roughly the size of two American football fields.
The spectacle didn’t last long, though. By Aug. 5, new satellite images showed no trace of it anywhere on the lake.
According to BC Hydro spokesperson Bob Gammer, that doesn’t necessarily mean it sank. The more likely explanation, he said, is that it drifted back toward a sheltered section of shoreline, where it would be far harder to detect from above.
How a Floating Island Forms
Rare as it is, the phenomenon is well understood in limnology — the study of inland waters.
Over years, logs and branches washed in by the water build up along the edges of lakes and reservoirs. As that woody debris slowly decomposes, it forms a dense organic mat. Seeds and root systems take hold in the mat, and in the most developed cases, full-grown trees eventually take root on top of it.
As long as the mass remains attached to the lakebed or shoreline, it goes largely unnoticed. It’s only when water levels rise enough to lift it free that things change.
At that point, it begins drifting on its own, carried along by wind and current like a real island—even though nothing holds it to solid ground.
Why It Appeared This Year
It had already been an unusual year for Williston Lake.
Heavy snowfall the previous winter, followed by persistent summer rains, filled the reservoir to levels not seen in 14 years. BC Hydro was forced to open the dam’s spillways between June and July to release the excess.
The prolonged high water also reached stretches of shoreline that are normally dry. Residents reported that dunes commonly used for off-road riding were submerged this year, and that far more timber and vegetation than usual was swept out toward open water.
Together, these were exactly the conditions needed to tear a tree-covered stretch of shoreline loose and set it adrift.
Where Else Islands Like This Have Appeared
Williston Lake is far from unique.
Major tropical rivers produce floating islands fairly regularly during floods. The Congo River in Africa once swept such fragments up to 149 miles offshore from its mouth.
In Papua New Guinea’s Sepik River, these formations are so common after the monsoon season that the local language has its own name for them, “Lik Lik Aislans,” with some reaching over 328 feet wide and supporting mature trees.
In South America, floods along the Paraná River and the Río de la Plata trigger a similar phenomenon known as camalotes, though these consist primarily of floating aquatic vegetation rather than logs with rooted trees.
In Germany, Lake Kleiner Arbersee hosts a more stable version of the same process: a peat platform firm enough to permanently support mature trees.
And in Sweden, as early as the late 19th century, scientists analyzed gases trapped inside a floating island in Lake Ralången to better understand what kept these structures afloat.
Where the Williston Island Stands Now
At present, BC Hydro expects no impact on normal dam operations.
Even so, the utility acknowledges that these islands can become a serious hazard if they drift toward the water intakes of hydroelectric power plants — a scenario that has already caused complications at other reservoirs worldwide with similar conditions.
In the meantime, the company keeps monitoring the reservoir, waiting for the island to reappear in a future satellite image.
It may already be back, tucked away in a quiet cove of the reservoir, waiting for the next flood to set it free again.
Or it may simply have broken apart along the way, returning piece by piece to the very water it once rose from.
