KATHMANDU: Meteorologists have warned that the risk of rainfall continues in the Madhesh and Koshi Provinces.

According to experts, the intensity of the continuous rainfall that began Friday night is expected to increase on Saturday night.

Due to a low-pressure line developed over the Bay of Bengal, very heavy rainfall was recorded on Saturday afternoon in Bara, Parsa, and Rautahat districts of Madhesh Province, while moderate rainfall occurred in Kathmandu Valley and other parts of the country.

Min Kumar Aryal, a meteorologist at the Department of Hydrology and Meteorology, said that although rainfall intensity in Kathmandu Valley will increase on Saturday night, it is expected to remain at a moderate level.

“Moderate rain is expected in Kathmandu Valley Saturday night, but the intensity will be higher than in the afternoon,” Aryal told Nepal News.

“Continuous rainfall increases the risk of flooding, landslides, and soil erosion,” he added.

Rainfall intensity generally increases at night because the weather cools down, whereas during the day, evaporation reduces rainfall.

Heavy rain was recorded on Saturday evening in Sarlahi and Makwanpur.

Kathmandu Valley received moderate rainfall.

According to the meteorological department, rainfall exceeding 200 millimeters in 24 hours is considered heavy.

Aryal added that both sudden heavy rain and continuous overnight rainfall pose significant risks.

“The state of the drainage system determines the level of risk. Poor drainage can lead to waterlogging and flooding,” he explained.

“Prolonged rainfall reduces soil absorption capacity, increasing potential damage,” he added.

During a Saturday afternoon meeting at the Ministry of Energy, Water Resources, and Irrigation, Director General Kamal Ram Joshi stated that very heavy rainfall was expected between 10 PM and 2 AM on Saturday night.

“The weather system will continue to bring rain from 8 PM Saturday until 8 AM Sunday, with the heaviest rain expected between 10 PM and 2 AM,” he said.

Joshi urged special vigilance in Madhesh, Bagmati, and Lumbini provinces.

He advised riverside residents to remain alert and suggested relocating people in flood- and landslide-prone areas to safe locations immediately.

On Saturday afternoon, rainfall measurements showed 10–15 millimeters per hour in Kathmandu Valley and 30–80 millimeters per hour in Madhesh.

Binod Pokharel, Associate Professor at Tribhuvan University’s Department of Meteorology, said that as the rain system moves eastward, rainfall in Kathmandu Valley will decrease in 3–4 hours.

However, eastern Nepal is expected to experience rainfall until Sunday.

As of 9 PM Saturday, 24-hour rainfall totaled 354 millimeters in Maheshpur, 337 millimeters in Gaur, and 305 millimeters in Garuda of Rautahat.

In the past three hours, 108 millimeters were recorded in Hariharpurgadhi and 217 millimeters in Malangwa, Sarlahi.

Nepal’s annual average rainfall is 1,400 millimeters.