Heavy rain accompanied by tornadoes, lightning, hail and strong winds can affect human life and agricultural production.

The low pressure trough currently has an axis at about 24 - 27 degrees North latitude. From May 19, it will be compressed and pushed to the South, combined with wind convergence up to 3000 m, gradually becoming stronger in the Northern region.

Therefore, from around May 19 to the morning of May 21, areas in the province are likely to experience widespread heavy rain with rainfall ranging from 80 - 120mm/period, some places over 120mm/period. Moderate and heavy rain will be concentrated in the following localities: Bat Xat, Sa Pa, Bac Ha, Si Ma Cai and the Northwest of Lao Cai city. The period of heavy rain will be concentrated from the night of May 19 to the morning of May 20, followed by scattered showers and thunderstorms, with localized heavy rain.

Heavy rain over many days increases the risk of flash floods and landslides in mountainous areas (Sa Pa, Bac Ha, Bat Xat, Muong Khuong) and flooding in low-lying areas along rivers and small streams (south of Lao Cai city and Bao Yen district).