The incident took place at Patel maidan in Samastipur where Manjhi had gone to unveil a statue of former Union minister Late Baliram Bhagat yesterday.
Sub Division Officer (SDO) Sudhir Kumar told PTI today that the chopper was caught in slush because of heavy downpour under the impact of cyclone Hudhud.
There was no problem on the ground when the helicopter had arrived in the aftenoon. After the rains, the helipad turned slushy, the SDO said.