At least 12 people have died and many villages been submerged after heavy rains caused severe flooding in southern Thailand.
Hundreds of thousands of people have been affected with water levels reaching "roof-high" in some areas, Thailand's interior ministry said.
Transport services, including flights, have been disrupted and rescue efforts are under way to reach those stranded.
The heavy downpour is expected to continue for at least two more days.
The flash floods have also damaged hundreds of schools and toppled power cables across southern Thailand.
Residents in villages across the region are using inflatables, such as rubber rings, to cross submerged roads.
Meanwhile, the airport in Nakhon Si Thammarat province has been forced to close after the area received a record 162mm (6.4 in) of rain on Friday, officials said.
An official for Thailand's Meteorological Department told AFP news agency that the situation was "very bad", adding that it was still "raining heavily" in the south.
In response to the crisis, the Thai navy has stationed its largest ship in the South to act as a floating command centre, dispatching aid using helicopters and small boats.
Last month, aerial footage showed flood damage to parts of southern Thailand with only rooftops visible above the flood waters. Supplies were being delivered to residents by boat.
Despite it being dry season between November and January in central and northern parts of Thailand, this time of year can see some of the heaviest rainfall in the southwest, where temperatures are more consistent throughout the year.
In 2011, devastating floods in Thailand displaced thousands of people in more than a third of the country's provinces, resulting in more than 600 deaths.