This flood was result of sudden increase in water discharge due to torrential rain in the foothill of the Himalayas in Nepal and adjoining areas in Bihar between August 12 and 20 led to flash flood in various rivers[17] — Gandak, Burhi Gandak and Bagmati, Kamla, Kosi and Mahananda — due to heavy rain in the catchment areas of the major rivers of North Bihar in Nepal.
Bihar government records put animal deaths in the State at 192; it announced compensation of ₹30,000 for the loss of every milch cow and buffalo and ₹3,000 for a goat.
[23] The swollen Gandak engulfed about 168 villages and 44 panchayats under 8 blocks of Saran district- Panapur, Taraiya, Parsa, Maker, Dariapur, Amnour, Marhoura and Masrakh.
[27][28] On 26 August 2017, Prime Minister Narendra Modi announced a Rs 500 crore (78 million USD) central assistance for flood hit areas of Bihar and ex gratia of Rs 2 lakh to the next of kin of each of the deceased from the PM Relief Fund, AIMIM Chief Asaduddin Owaisi party donated over ₹ 5 crores aid to the victims in August 2017 and sent medicines worth Rs 50 lakh and a medical team to Bihar's flood-affected region Bihar cabinet sanctioned the amount when the toll was 400.
In October 2017, officials of an inter-ministerial team of the Centre Government held discussions in Bihar for assessing the damages caused by the floods in the state.