The government said landslides that struck remote areas in the central Quang Nam province late Wednesday evening, killing 13 people and leaving 40 missing as rescue efforts were disrupted by bad weather at the end of the storm. State media said 12 fishermen were killed at sea.
“We can predict the course of the storm or the amount of rain, but we cannot predict when the landslides will occur,” Deputy Prime Minister Trin Dinh Dung said in a statement.
“The road is covered with heavy mud and heavy rain is still hitting the area, but rescue work must be carried out quickly.”
On Thursday, state television said, the bodies of 12 fishermen were found after their boats sank while trying to return to shore two days earlier. Two navy ships have been mobilized to find them, and 14 are still missing.
Since early October, Vietnam has been hit by storms, torrential rains and floods that have affected more than one million people.
The government said Hurricane Mulaf – also known as Quinta – left millions of people without electricity and damaged 56,000 homes. It weakened to a tropical depression after making landfall on Wednesday and is expected to reach Laos later Thursday.
The Vietnam Meteorological Agency said heavy rains of up to 700 mm (27.5 in) will continue in parts of central Vietnam through Saturday.
Before hitting Vietnam, Typhoon Mulaf passed through the Philippines, causing floods and landslides that disaster authorities said Thursday had killed at least 16 people.
This story has been updated.