PATNA/bettiah, Aug. 27 -- The authorities in Bihar placed several north-western districts on high alert on Wednesday after flash floods triggered by a glacial lake outburst in Tibet sent a surge down the Bhote Koshi river in Nepal, raising the prospect of a sudden rise of up to around three metres in the Gandak river downstream. Over 100 people reportedly died and nearly 500, including 133 Indians, were missing after a torrential flash flood originating in Tibet swept through central Nepal districts. A statement from the water resources department (WRD) said a glacial lake outburst around 9 am in the Tibet region generated an approximately three-metre flood wave that travelled down the Bhote Koshi, a headwater tributary of the Trishuli-Narayani system that ultimately feeds the Gandak. The river enters Bihar at Valmikinagar in West Champaran. Officials flagged the possibility of a flood wave carrying 200,000-300,000 cusecs reaching the state. At the Devghat gauge site on the Narayani in Nepal (about 80 km upstream of Valmikinagar), the water level stood at 4.77 metres - well below the warning level of 7.30 metres and the danger mark of 9.00 metres. Any further rise was expected to reach the Valmikinagar barrage in roughly 3.5 hours. Discharge at the barrage rose steadily through the day: around 86,000 cusecs in the morning, 99,945 cusecs by 10 am, and 1,44,800 cusecs by 4 pm. Executive engineer Iqbal Anwar of the head works division earlier indicated rising levels at Devghat and warned that roughly 300,000 cusecs could arrive within five to six hours. Again at 5pm, the discharge from Valmikinagar barrage was 106,000 cusecs. As a precaution, all 36 gates of the Valmikinagar barrage (designed capacity 850,000 cusecs) were opened in phases and canal supplies disrupted. A technical team led by a superintending engineer was deployed for continuous monitoring. The WRD and Central Water Commission (CWC) had both highlighted the risk of a significant surge. Chief minister Samrat Choudhary convened a high-level review at his official residence and directed officials to remain on high alert. He formed a committee under chief secretary Pratyaya Amrit and the director general of police (DGP) to monitor the situation closely. "A close watch is being kept on the possibility of a rise in water level in the Gandak in view of the floods in Nepal. If necessary, I will also visit Valmikinagar to assess the situation," the chief minister told reporters. He held meetings with the chief secretary, principal secretary (disaster management) and secretary (WRD). Deputy chief minister Vijay Kumar Chaudhary, who holds the WRD portfolio, said in a video message that the next five hours would be critical and urged people to stay alert but calm, noting that the administration was fully prepared. Union home minister Amit Shah spoke to the chief minister, assuring full central assistance and directing mobilisation of National Disaster Response Force (NDRF) teams. Chief secretary Pratyaya Amrit chaired a video conference with district magistrates and senior police officers from the affected belt. Special vigilance was ordered in West Champaran, East Champaran, Gopalganj, Saran, Muzaffarpur and Vaishali, along with Sitamarhi, Sheohar and other vulnerable areas. Officials were instructed to monitor water levels, embankments, low-lying areas, bridges and other critical points; maintain continuous night patrols; use loudspeakers to warn residents living inside embankments; ensure timely evacuation; stockpile relief materials; and keep boats, shelters and community kitchens ready. An NDRF team was sent to Gopalganj, with another on standby in Muzaffarpur and arrangements underway for deployment in Bettiah. The Sashastra Seema Bal placed 11 quick-response teams on immediate readiness and seven more on standby along the India-Nepal border. Vulnerable pockets identified for priority action include Jhandu Tola, Bin Toli, Chakdahwa and Kailashnagar in Bagaha, villages under Sisayi and Chiurahi panchayats, Baluwa, Bajuwa, parts of Nautan, and low-lying stretches in Sangrampur, Paharpur, Kesariya, Areraj, Sahebganj, Saraiya and Paroo blocks. West Champaran district magistrate Taranjot Singh confirmed activation of all field formations. Evacuation of about 250 families from low-lying areas in Jhandu Tola, Bin Toli and Chakdahwa was underway, with temporary shelters arranged at a government school in Bherihari and other locations. Gopalganj district magistrate Sameer Saurabh said a 30-member NDRF team and an SDRF contingent had been positioned near Chawahi amid pressure concerns at the Haujepur embankment. Disaster management minister Ratnesh Sada stated that dry rations, relief material and boats had been arranged and that the state was prepared for any eventuality. Authorities appealed to residents not to panic, to ignore rumours, to rely only on official advisories and daily media briefings by district magistrates, and to follow evacuation instructions if issued-particularly those in low-lying and diara areas. Social media monitoring was intensified to curb misinformation. Additional NDRF/SDRF teams and resources would be deployed as required. In Nepal, the sudden surge through the Bhote Koshi caused extensive devastation in districts including Rasuwa, Nuwakot, Dhading, Gorkha, Lamjung and Tanahun, killing at least eight people (reports ranged higher) and leaving hundreds missing, among them Indian nationals, foreign tourists, Nepali citizens and security personnel. Videos showed homes and vehicles swept away, bridges collapsing and settlements submerged. Hydropower projects suffered major damage. Chinese state media reported significant casualties feared in Tibet's Gyirong area after mudslides. Search-and-rescue operations continued on both sides of the border. The Bhote Koshi originates in Tibet, joins the Trishuli-Narayani system in Nepal and ultimately contributes to the Gandak, which flows into Bihar. Officials stressed that while the upstream flood wave posed a clear risk, continuous monitoring of levels at Devghat and Valmikinagar, combined with the barrage's capacity and pre-emptive gate operations, formed the core of Bihar's defensive posture....