Delta struck the archipelago with winds gusting at more than 100 kilometres
per hour, leaving a trail of destruction in its wake overnight before spinning off towards the Moroccan coast.
The storm shocked meteorologists.
"It's just not normal, first in that a storm forming off the Azores tends to brew up further south.
"That it should then come east towards Europe, and to the zone and latitudes of the Canaries, is a very unusual phenomenon," said Angel Riva, of Spain's National Meteorological Institute.
Global warming
Mr Riva said an unusual pattern appeared to be emerging following Tropical Storm Vince, which hit Spain in October.
Asked what caused the storm he said, "It is difficult to know. People talk about climate change and what we know is that the planet's average temperature is rising.”
"Undoubtedly a rise in temperature must in some way influence these phenomena, but we don't know to what degree," he said.
Tropical Storm Delta left a trail of destruction with about 20,000 people without power, mainly on Tenerife.
Local authorities reported that many roads were cut off and six ports had to
be closed.
Classes were suspended for 320,000 schoolchildren.
A local spokesman said that "an old man died at Puerto Rosario on the island of Fuerteventura," falling from his roof after dawn as he was trying to repair it.
Drownings
The fatality took the casualty toll to seven with at least six African immigrants drowned in stormy seas about 400 kilometres to the south of the islands.
According to local officials, between 10 and 12 people who were on the same
vessel as the victims are listed missing and 32 seriously injured survivors were taken to hospital in Las Palmas.
A slew of internal flights to and from the island of La Palma, a popular destination with British and German tourists, had to be cancelled.
One charter flight coming in from Amsterdam had to be diverted to Tenerife while approximately 400 people had to spend the night at La Palma airport as violent winds and the heavy rain continued to batter the area.