(CNN) People in Greece and Turkey are bracing themselves for a rare and powerful hurricane-type storm in southern Europe's Mediterranean region, due to hit this weekend.
The storm, often called a "Medicane" (Mediterranean + hurricane) has features similar to hurricanes and typhoons.
According to a study published in 2011, only about 1-2 "Medicanes" occur per year. These powerful storms usually happen during the months of September and October, when sea surface temperatures in the Mediterranean are still quite warm, although they can occur at any time of year.
The current storm, called Zorba, triggered flash flooding across Tunisia and Libya over the past few days before moving north over the Mediterranean towards Europe.
Over the sea, the storm is likely to pick up more tropical-like features normally associated with hurricanes, such as gale-force winds and even an eye in its center.
The area currently most under threat are the Ionian islands on Greece's western coast where the Hellenic National Meterological Office has put out a severe warning.
The system is expected to move slowly over the island of Crete and southern Greece on Saturday before picking up speed and heading into western Turkey on Sunday.
On Crete and other southern islands of Greece, as much as 4 to 6 inches (100 to 150 millimeters) of rain could fall, which could lead to flash flooding. Cities like Izmir, Turkey, and Kalamata, Greece, could see 2 to 3 inches (50 to 60 milllimeters).
That is cause for concern in the Aegean islands, including Lesbos, where thousands of refugees, many from Syria and Iraq, are being held in crowded conditions. Also under threat is the coastal area east of Athens recently devastated by the worst fires on record that killed 99 people.
A number of ferry services connecting Athens to the islands, were not allowed to operate for the last two days but have now largely resumed. Many flights were also grounded due to the strong winds.
Schools in Athens remained closed Friday for precautionary reasons after the gale force winds knocked out power lines in several Greater Athens areas while a felled tree destroyed the roof of a school in western Athens.
Civil protection services will be on alert throughout the weekend, the government said. Civilians have been advised to exercise caution and avoid unnecessary travel.
Fortunately, the Medicane will likely get absorbed into the upper-level jet stream and will not linger over southeastern Europe, which will limit the amount of flooding from the storm.
Recent major systems such as hurricanes Harvey and Florence produced catastrophic flooding because of their slow-moving nature.