The weather department has predicted heavy downpur for Himachal Pradesh, Uttarakhand and Jammu and Kashmir.
Heavy rain in several parts of north India has brought the region to its knees, claiming more than 34 lives in the past three days.
In cities and towns, many roads and buildings remain submerged in knee-deep water.
The weather department has predicted more downpour for Himachal Pradesh, Uttarakhand, Punjab, Haryana, Jammu and Kashmir, Rajasthan, Delhi and its adjoining areas over the next couple of days.
Frightening images of the chaos - vehicles floating like paper boats, muddy waters gushing into residential areas, structures submerged on the banks by the swollen rivers and land cave-ins - were shared online by people from Himachal Pradesh, Uttarakhand and Delhi.
In Himachal Pradesh, landslides and flash floods, triggered by incessant rain, damaged houses, structures and paralysed normal life. Some shops and vehicles were also washed away in flash floods in Manali, Kullu, Kinnaur and Chamba as all major rivers - including Ravi, Beas, Satluj, Swan and Chenab - are in spate.
Chief Minister Sukhwinder Singh Sukhu has appealed to people to stay indoors for the next 24 hours. "I want to request all residents of the state, please stay home for the next 24 hours because very heavy rain is expected. We have started three helplines -- 1100, 1070, 1077. You can call up these numbers to share information about anyone stuck in the calamity. I am available round the clock to help you," he said in a video message.
"So far, more than 20 people have lost their lives majorly due to road accidents and similar reasons. The loss of lives due to landslides and flash floods is not as high. Over 1,300 roads, including major national highways, district, and link roads in the state, are affected. We are on high alert for the next two days," Himachal Pradesh Minister Jagat Singh Negi said today.
Landslides and flash floods were reported in neighbouring Uttarakhand too, with reports of water level in rivers and streams crossing the danger mark.
All schools in Gurgaon and Delhi remain shut today as heavy rain has led to waterlogging. The Gurgaon administration has also advised corporate houses to work from home today to avoid traffic jams.
The Delhi government has set up 16 control rooms to monitor the flood-prone areas after Haryana released more than one lakh cusecs of water into the Yamuna river from the Hathnikund barrage.
Chief Minister Arvind Kejriwal chaired a high-level meet to discuss waterlogging caused by rain in the city and Yamuna's rising water levels. Floods are unlikely in Delhi, Mr Kejriwal today said, quoting predictions made by experts. If needed, we will shift the people from low-lying areas to safe spots, he added.
A red alert has been issued for Kathua and Samba districts of Jammu and Kashmir. Although, the Amarnath Yatra resumed on Sunday from the Panjtarni and the Sheshnag base camps after remaining suspended for three days.
Heavy rain in several parts of Rajasthan, Punjab and Haryana led to massive waterlogging and flooding in low-lying areas, prompting authorities to swing into action in the worst-hit places.
The IMD said an interaction between a western disturbance and monsoonal winds is leading to an intense rainfall spell over northwest India.