Rescue teams in central Greece are searching for at least five people who are missing after flash floods that killed 15 people.
Some roads have reopened in the three hardest-hit towns near the capital, Athens. But schools and other public services remain closed.
Prime Minister Alexis Tsipras has visited the area hit by the "disastrous flood".
Bad weather is expected to continue until the weekend.
Food, water and blankets have been sent to the worst-affected industrial towns of Mandra, Nea Peramos and Megara, west of Athens, where local officials say the situation is unprecedented.
Many people have been left homeless after their houses were inundated by the torrents of reddish mud. A 364-cabin cruise ship has been offered as a shelter.
"It was like a tsunami," Evangelos Kolovetzos, a local shop owner, told AFP news agency.
Some areas are still without water and electricity and it may take days to repair much of the damage.
The victims included elderly people who were trapped inside their homes.
A three-day state of emergency has been declared.
Experts have blamed illegal construction in the area, which obstructed the natural path for water runoff.