Police investigating an offence of outraging public decency on the canal towpath between Hebden Bridge and Mytholmroyd have released an e-fit image of the suspect.
The offence of outraging public decency is reported to have happened at 9.15am on Saturday, May 23.
The man involved is described as white, aged over 65-years-old, of thin build, of a pale complexion with blue eyes, a gaunt face and prominent chin.
He was wearing a dark green raincoat, light chino trousers and a woolen black hat and may have been carrying a rucksack. He is described as being unshaven.
PC Chris Holt, of Valley North Neighbourhood Policing Team, said: “The man is not reported to have spoken to the victim or engaged with her in any way but his actions have left her feeling shaken and frightened.
“Two female joggers were passing nearby and may have seen this man. They are described as aged in their 40s, one wearing a black top with pink on the arms and black lycra leggings.
“We are keen to identify and speak to these women as part of our ongoing enquiries.
“We would urge these women and anyone else who was either in the area or who has information about the man involved to call Valley North NPT via 101.”