They said he attempted the trip even though his girlfriend had “never undertaken an Alpine tour of this length, difficulty, and altitude, and despite the challenging winter conditions”.
They also allege he started out two hours too late and had failed to take “enough emergency bivouac equipment”.
He also “allowed his girlfriend to use… snowboard soft boots, equipment that is not suitable for a high-altitude tour in mixed terrain”, say prosecutors.
The defendant disputes this. In a statement, his lawyer Kurt Jelinek, said the couple had planned the tour together.
“Both considered themselves… to be sufficiently experienced, adequately prepared, and well equipped,” he said. Both had “relevant Alpine experience” and were “in very good physical condition”.
Once on the mountain, prosecutors say the man should have turned back, when it was still possible, because of strong winds of up to 74km/h (45mph), and the winter cold. It was -8C, with a windchill temperature of -20, they said.
The couple did not turn back.
Accounts of what happened next differ.
According to the defendant’s lawyer, they reached a place called Frühstücksplatz at 13:30 on 18 January, the point of the tour after which there was no turning back before the summit.
As neither of them was “exhausted or overwhelmed, they continued on”, Kurt Jelinek said.
Prosecutors say the couple got stuck at about 20:50 and that the man failed to call the police and did not send any distress signals when a police helicopter flew overhead at around 22:50.
The boyfriend’s lawyer said at that point his client and girlfriend still felt fine and did not call for help as they were close to the summit.
Webcam images show lights from their torches, external as they scaled the mountain.
