The Quang Ninh Hydro-Meteorological Station said moderate to heavy rain since August 20 had left soil more than 85 per cent saturated in some areas and fully saturated in others.
Storm Narra, which strengthened from a tropical depression over the Gulf of Tonkin on Friday, is forecast to bring further heavy rain and thunderstorms, with possible tornadoes, lightning and strong gusts.
On Saturday, waters off Quang Ninh and around Co To Special Zone are forecast to see northeast winds of level 4-5, gusting to level 6-7, with waves of 0.75-1.25 metres. Visibility could fall to 2-4 kilometres in rain, posing risks to maritime activities.
Continued heavy rain on already saturated ground has put many areas at very high risk of flash floods, landslides and subsidence, with the natural disaster risk level set at one.
Warnings cover Halong, Cam Pha, Uong Bi, Dong Trieu and Quang Yen, as well as Van Don and Co To special zones. Mountainous and border areas including Ba Che, Binh Lieu, Tien Yen, Luong Minh, Ky Thuong, Quang Duc, Hai Son and Hoanh Mo are also at risk.
Authorities warned that flash floods and landslides could threaten lives, cut off roads and damage homes and other infrastructure.
Residents have been advised to closely follow weather warnings, avoid flooded crossings, rivers and streams during heavy rain, and stay away from steep slopes and areas showing signs of landslides.
People in high-risk areas should move themselves and their property to safer locations and immediately alert local authorities to landslides, blocked waterways or other hazards.
