Sastrugi sea ice than on multiyear ice. First-year ice is smoother than multiyear ice, which allows the wind to pass uniformly over the surface without topographic obstructions. Except during the melt season, snow is dry and light in climates cold enough for sea ice, allowing the snow to be easily blown and create sastrugi parallel to the wind direction. The locations of sastrugi are fixed by March in the northern hemisphere and may be linked to the formation of melt ponds. Melt ponds are more likely to form in the depressions between zastrugi on first-year ice. Sastrugi Sastrugi, or zastrugi, are
Origin of the Oak Ridges Moraine a 20 m layer of shallow surface Oak Ridges Moraine sediments, underlain by the "Newmarket Till". The other wedges, which peak at up to 335 m, have thicker and more varied surficial deposits, and the "Newmarket Till" lies deeper below the surface. Moreover, the sedimentary deposits are underlain by "Halton Till" on these wedges, which is not present in the Rice Lake wedge. Thus, from top to bottom, the stratigraphy of the moraine is: The most accepted theory of the development of the Oak Ridges Moraine is that proposed by Barnett et al. (1998). "Moraine development is highlighted in four