Welden was a sophomore at Bennington College in Bennington, Vermont in 1946; she was studying art. She resided with her parents in Connecticut when she was not at school.

Welden was last seen on December 1, 1946. She worked two shifts at the dining hall, came back to her room and spoke to her roommate for awhile before declaring she wanted to go for a walk. Welden was last seen walking on the Long Trail near Glastenbury Mountain. An extensive search of the area, involving officials from Massachusetts and New York as well as Vermont, turned up no sign of Welden. She was underdressed for the cold weather on the day of her disappearance.

Two years after Welden's disappearance, authorities arrested a man for slashing another man and robbing him. The suspect had newspaper clippings about Welden's case in his pockets at the time of his arrest. Authorities investigated and tried to link him to Welden's case, but no evidence was uncovered to suggest he was responsible for her disappearance.

Foul play is suspected in Welden's case. At the time of her disappearance, Vermont had no state police force. The inability of local authorities to deal with her disappearance lead to the establishment of the Vermont State Police. Welden enjoyed watercolors, pencil and charcoal sketching, skating, bike riding, hiking, camping, swimming, square-dancing and guitar playing in 1946. She has work experience as a waitress. Her case remains unsolved.