Police Scotland said they were made aware of the avalanche at around 3.35pm on Friday.
The Lochaber Mountain Rescue Team and a helicopter were dispatched to help two male climbers who were in the area at the time.
A 48-year-old man was pronounced dead at the scene and a 40-year-old was taken to Belford Hospital in Fort William for treatment. Next of kin have been informed.
The mountain rescue team posted an update on the incident on its Facebook page, saying the men were found at number two gully on the north face of the mountain.
It said: “Sadly one had sustained fatal injuries and the other was seriously injured after a slide of 600 metres (approximately).
“With the weather creating some challenging conditions the helicopter was limited to the assistance it could offer.
“This meant that we had an extended extrication of the casualties and 8 hours after the initial call we delivered the casualty to the Belford Hospital for further assessment and treatment.
“At this time, our thoughts are with the families of both involved.”