B.C.’s ‘missing’ floating island found, though questions remain

BC Hydro says it has located a small floating island that appeared on B.C.’s Williston Reservoir, seemed to vanish in mid-August and then drew international attention. The island is now on the shore of the reservoir’s Ospika Arm, though questions remain about how it formed and moved.

The utility first learned of the vegetated island on Aug. 13 after receiving photographs and video believed to have been taken around July 21. It confirmed the island’s location on Aug. 31 using satellite imagery dated Aug. 15, observations from an aircraft and reports from local boaters. BC Hydro said the island drifted 30 kilometres in 15 days.

Community relations manager Bob Gammer said the utility was initially unconvinced by reports of a tree-covered floating island and needed to verify them, particularly in an age of artificial intelligence. Once confirmed through satellite imagery and other observations, he said, it captured the public and media’s imagination and attracted scientists studying how vegetated floating islands form and move.

The latest photographs show the island remains intact with established vegetation. BC Hydro estimates it is about the size of two football fields, measuring 70 metres wide and 140 metres long. Such islands are uncommon at that size but can occur on large reservoirs. Williston Reservoir is B.C.’s largest and among the world’s largest by volume, which BC Hydro said helps explain why the island escaped notice for a time.

One possible explanation is that logs and woody debris accumulated over a long period in a sheltered area. After years of decomposition, vegetation may have taken root and created a stable mass of interconnected debris and plant growth. BC Hydro says it will continue monitoring the island and learning about its origins and movement.