Shimla, July 19 -- The India Meteorological Department (IMD) has issued a red alert for heavy rainfall in parts of Himachal Pradesh on July 20 and 21, warning of flash floods, landslides, rising river levels and widespread disruption as monsoon activity is expected to intensify across the state from the night of July 18. Speaking to the media in Shimla on Saturday, senior scientist at the IMD's Meteorological Centre, Shimla, Sandeep Kumar Sharma, said the weather system is expected to remain active until at least July 24, with the most intense spell likely on July 20 and 21. "The weather is expected to become active from the night of July 18. Light to moderate rainfall will occur across many parts of the state, while heavy to extremely heavy rainfall is likely in several districts over the next few days," Sharma said. He said a yellow alert has been issued for Chamba, Kangra, Kullu and Mandi for July 18, where isolated places are likely to receive heavy rainfall. The weather activity is expected to intensify on July 19, with the IMD issuing an orange alert for Kangra, Mandi and Shimla for heavy to very heavy rainfall. Yellow alerts have also been issued for Chamba, Hamirpur, Kullu, Sirmaur, Solan, Una and Bilaspur. Sharma said the most severe weather conditions are expected on July 20, when a red alert has been issued for Chamba, Kangra, Mandi and Sirmaur, where isolated places may experience extremely heavy rainfall. An orange alert has been issued for Una, Bilaspur, Hamirpur, Kullu and Shimla. A massive landslide occurred in the Gahar Da Ghatu area of the Chuwari-Bharari Road in Chamba due to rainfall on Saturday. A large section of the road caved in, disrupting traffic, and a vehicle was left dangling precariously towards the gorge. However, no casualties have been reported. The incident took place while a vehicle was passing along the road when a section suddenly collapsed, leaving the vehicle hanging at the edge of the gorge. Panic ensued at the scene. Upon receiving the information, a team from the concerned department arrived at the site. Two JCB machines have been deployed to safely retrieve the vehicle and restore the road for traffic. Relief and restoration work is proceeding rapidly, with the administration aiming to reopen the road as soon as possible. Due to continuous rainfall, the risk of landslides persists in several other areas of the district as well....