Boaters in northern British Columbia are being warned to stay away from a mysterious floating island that has reappeared on Williston Lake after drifting about 30 kilometres in two weeks. ^[1] Rocky Avery, a resident of British Columbia, spotted a large mass of green vegetation floating freely on Williston Lake while boating. ^[2] Satellite imagery from the European Space Agency's Sentinel-2 satellite confirmed that the floating mass is a real object located in Williston Lake. ^[3] Local resident Rocky Avery posted videos on social media showing a large floating island covered in trees and vegetation moving across Lake Wabamun in British Columbia, Canada. ^[4] A mysterious forested island approximately one hectare in size appeared in the Williston Reservoir in British Columbia, Canada, and was later confirmed to have moved and disappeared. ^[5] BC Hydro spokesperson Bob Gammer said he initially thought reports of the island covered in trees and foliage on Williston Lake were a hoax, but satellite images confirmed its existence in mid-August. ^[6] Gammer said the island appears to be intact, is about 140 meters long and about 70 meters wide, and is naturally unstable, making it unsafe to climb onto or land a boat on. ^[7] The floating island, measuring about one hectare, disappeared and was then spotted again on Monday after travelling about 30 kilometres northwest on the reservoir. ^[8] Barry officials noted that Williston Lake has reached full capacity for the first time in 14 years, and rising water levels likely tore a section of the vegetated shore loose. ^[9] Experts describe the floating object as a giant raft of vegetation with interlocked roots rather than a traditional island. ^[10] BC Hydro officials stated that record-high water levels, the first in 14 years, likely caused the island to form by freeing debris that was previously stuck along the shoreline. ^[11] Satellite images from the Sentinel-2 system, operated by the European Space Agency, captured the green surface approximately 100 kilometers west of the W. A. C. Bennett Dam on July 21, 2026. ^[12]