A stretch of the National Highway-3 was closed for vehicular traffic following a flash flood triggered by a cloudburst in Himachal's Kullu district, police said on Thursday.

No casualty has so far been reported in the incident that occurred late Wednesday, they said.

According to officials, the stretch between Dhundi and Palchan Bridge on NH-3, also known as Leh-Manali Road, was affected due to the cloudburst at Anjani Mahadev nullah in the Manali area.

Vehicles headed to Manali from Lahaul and Spiti via the north portal of the Atal Tunnel have been diverted towards Rohtang, the Lahaul and Spiti police said in an advisory on Thursday.

It also asked the commuters to travel only if necessary, drive cautiously, and stay aware of the possible danger en route.

A total of 15 roads, including 12 in Mandi, two in Kinnaur and one in Kangra district were closed for vehicular traffic while 62 transformers were disrupted in the state on Wednesday night, the state emergency operation centre said.

There have been reports of damage to a power project and a few houses but these are yet to be confirmed by officials who are assessing the damage.

The local Met office on Wednesday issued a 'yellow' alert of heavy rain at isolated places in Himachal Pradesh for the next four days till July 28. It cautioned about damage to plantations and standing crops, vulnerable structures and 'kutcha' houses in the state due to strong winds and waterlogging in low-lying areas.

A total of 49 people have died in rain-related incidents in the state, which has suffered losses of approximately Rs 389 crore, since the onset of monsoon on June 27, the emergency operation centre said.