Ms Buick was reported missing in the area on Tuesday June 22.
She posted a selfie from the summit of Ben Nevis at around 5am on Tuesday but was not seen or heard of since.
A police appeal was launched on Wednesday to trace the experienced walker.
Inspector Nick Hough of Fort William Police Office said: “As time goes on we are becoming increasingly concerned for Sarah.
“She is an experienced walker and often makes trips alone, but it is very unlike her to be out of contact with friends and family for this length of time.”
Police confirmed there are no suspicious circumstances and that a report will be submitted to the Procurator Fiscal in due course.
More to follow
Body found during searches for missing woman Sarah Buick on Ben Nevis