Extraordinary sand sight to see

Comparable to nowhere else on Earth, the Athabasca Sand Dunes are an extraordinary place consisting of large dune fields, stretching for more than 62 miles along the south shore of Lake Athabasca. The sand dunes of Athabasca are the largest active sand surface located north of 58 degrees latitude and they are the most northerly set of major dune fields in the world. Sand dunes are considered to be alive and are classified as “active” because of the constant movement within them. The active sand dunes of Athabasca travel southeast at a rate of five feet per year. The passengers are intrigued by the expression “active sand surface” and want to know how the dunes move.

As the plane circles above the looming giants, the pilot explains that the unique dune fields of Athabasca are made up of a variety of styles. Depending on the strength and consistency of winds, amount of sand and presence of vegetation, there are four basic types of dunes; Barchan (crescent) dunes, Transverse dunes, Parabolic dunes and Longitudinal (seif) dunes. Some dunes in Athabasca have a classic parabolic shape, which is a U-shaped or V-shaped mound of sand that when viewed from the air, has elongated arms that extend upwind behind the dune. The constantly blowing wind lifts sands up from the center of the dune and blows it to the steeper, convex side called the slip face. The Slip face is usually a high angle, face down that slides and moves. Over time, the sand is eventually pushed over the top of the ridge, causing the dune to move forward. Other dunes in the Athabasca fields are transverse, horizontal to the strong, steady prevailing winds and formed in sand rich areas.

The constantly blowing winds of Athabasca move predominantly from the northwest to the southeast. The dune fields are aligned north to northeast and west to southwest so, as the years pass, the blowing winds move the sand from the dune fields into the William River. The William River, which is a braided stream, then carries the sand into Lake Athabasca. Because of the prevailing winds, the wave action on Lake Athabasca eventually deposits the sand back onto the south shore of the Athabasca Sand Dunes, and the cycle begins again.