The weather bureau yesterday warned residents in several northern provinces to prepare for heavy downpours and the possibility of flash floods and landslides.

Uttaradit, Lampang, Sukhothai and Tak were identified as high-risk areas.

In Uttaradit's Laplae district, landslides have already occurred in several areas, including Naree village, where 167 people were evacuated. Sensing trouble coming, Laplae district chief Thongchai Teyathiti ordered an evacuation on Monday.

"I have allowed only men who are good at riding motorcycles to stay overnight in the village. Their presence will help prevent thefts. But they have standing orders to get out if something goes wrong," Thongchai said.

Heeding the headman's advice, 36-year-old Sayan Timyam said he and his neighbours hit the road, leaving the village behind them yesterday as soon as they heard the noise of rushing water.

Another villager, Sompong Ounjaifan, 36, said local people were panicked and wanted to move somewhere else for good.

Roads to and from Naree are now virtually impassable, blocked by piles of earth and rocks from landslides.

Mineral Resources Department director-general Somsak Potisat said satellite photos showed dangerous conditions - rocks and mud piled high - in mountainous areas of Uttaradit, Sukhothai and Phrae.

"They are signs of danger - these piles could collapse on people living at the foot of the mountains when there are heavy downpours," he said. Provincial authorities had been advised and they were expected to contact people living in danger zones.

Uttaradit's disaster prevention and mitigation chief Nitipat Wiriyakul said Laplae and Tha Pla districts faced the greatest danger.

Meanwhile, the Water Resources Department said it had already installed an early-warning system in 210 villages across 30 provinces. Department director-general Siripong Hangsapruk said the system would sound alarms if rainwater-monitoring stations on hills detected a dangerous amount of rain.

"We plan to install early-warning systems in all 2,370 areas in the country considered at risk within the next three years," he said.

He said his department's early-warning system was hi-tech and would complement the system used by the Mineral Resources Department.

The Meteorological Department urged people to keep abreast of weather forecasts, as it expected a few large tropical storms to affect Thailand this rainy season.

"If these storms come close or actually pass through the country, they will bring heavy downpours and possible flash floods," it said.