No one was sure of the exact amount he had consumed but he was described as "legless" and "really pissed and stumbling around" in his socks and underpants, being loud and annoying.
At some time after 5pm, Christoffersen climbed onto a jetty-like structure beside the river which is used for taking river flow readings. It is also used by swimmers to jump off, despite signs warning of currents and deep water.
The Waikato River was flowing high and fast but conditions were not unusual and Christoffersen, who had lived in Taupo in the past, was said to be familiar with the area.
Witnesses said he climbed onto the platform handrail and then apparently misstepped or slipped, somersaulting into the water.
The first witness said she saw him come back up and he appeared okay. She looked away briefly and when she looked back, he was nowhere to be seen.
She ran up and down the riverbank looking for him. Some tourists downstream had seen him in the river but had thought he was swimming. When she could not find him, she called 111 for help.
Taupo Coastguard located Christoffersen's body in the river about 150m downstream from Reid's Farm at 7pm. Later that night, the Police Dive Squad retrieved the body from water 3.9m deep, about 8m out from the riverbank.
There were reports Christoffersen had earlier been in an altercation with another man and had suffered a bloody nose, although none of the three witnesses who gave evidence in court recalled seeing him with an injury.
In his findings, Coroner Matenga said alcohol and cannabis had contributed to the loss of control Christoffersen had experienced.
He found the presence of the platform and environmental issues were not contributing factors and, although the warning signage could be larger, signs were mostly ignored by the public anyway.
He noted the work the Taupo District Council and local iwi had done during 2017 to improve safety in the area, including closing some areas to vehicles and clearing bush.
Reid's Farm, now renamed Hipapatua Reserve, is a popular area for freedom camping, socialising and swimming about 5km north of Taupo.