Fierce flames lit up the skies of Tenerife in the early hours of Sunday as a wildfire raging in the north of the island raged out of control.
Residents said they had never seen fires of such magnitude on the island.
Emergency services in the Canary Islands said more than 26,000 people had been evacuated from their homes by Saturday afternoon, up from 4,500 on Friday. About 11 cities have been affected so far.
Scorching heat and dry weather this summer have caused extremely severe fires in Europe, including on the Spanish island of La Palma in July.
Scientists say climate change has led to more frequent and more powerful extreme weather events.