Tropical depression Noru, formerly a super typhoon, has left four northeastern provinces awash, with one person dead as it hit the upper section of Thailand on Thursday.

The storm has set off emergency alarms in 17 provinces in the North, Northeast and Central Plains, which have all braced for the risk of heavy flooding in the days to come.

From Wednesday night till Thursday morning, much of Amnat Charoen, Si Sa Ket, Yasothon and Ubon Ratchathani saw torrential rainfall and thunderstorms that led to floods.

Several main roads in these provinces were swamped, and strong winds knocked down trees in five districts across the four provinces.

In Si Sa Ket, one person was killed and two injured when a large tree toppled by a strong wind fell onto the pick-up they were travelling in.

As of 11am Thursday the depression was centred in Roi Et with a wind speed of 50 kilometres per hour. The storm was heading west and is expected to weaken further.

Despite the downgrade, the storm will continue bringing more rain to all parts of the country, especially the North and Northeast where strong winds are also forecast in the days ahead.