Bare Spots - Areas of exposed trail surface, not covered with sufficient skiable material.

Corn Snow - Large ice-like granules which are loose during above-freezing temperatures and which freeze together during below-freezing temperatures. Corn snow is usually a product of the above/below freezing cycle of temperatures typical of spring days. Large ice-like granules which remain frozen together in extended cold periods, or chunks of ice created by incomplete grooming or icy surfaces are not characteristic of corn snow.

Frozen Granular - Granular snow which was once wet and which has frozen together forming a rather solid or crusty-textured surface. It can return to loose granular after thawing or being worked by a grooming machine or from the effects of skier traffic breaking up the crust. Frozen granular snow will support a ski pole stuck into it. However, if the pole makes ice chips and the surface will not support the pole, the surface is icy.

Hard Pack - Hardpack snow is dense, compressed snow harder than packed powder and softer than ice.

Ice Patches, Icy Surface - Ice represents a hard, glazed surface usually created by freezing rain or old surface snow melting and quickly refreezing again, or by ground water seeping up into the snow and freezing. Also may describe a very wet surface that has been skied into a smooth surface while above-freezing temperatures are existent and then rapidly dropping temperatures occur. When broken, ice breaks into chunks rather than granules. "Patches" describe localized occurrences of ice; "surface" describes a more prevailing icy condition on the slope.

Loose Granular - Loose granules similar to rock salt, usually formed after powder snow thaws, refreezes and crystallizes; or an accumulation of sleet. Loose granular also may charactize surface conditions produced by machine conditioning of frozen granular or icy surfaces.

Powder - New snow generally of dry and fluffy consistency. Will not make a snowball easily.

Packed Powder - Loose powder snow compacted by rollers, drags or other mechanical apparatus or by skier traffic to a state which leaves little air space between particles. It is no longer fluffy, but it is not so extremely compacted that it is hard and icy.

Spring Conditions - This term is used to characterize the wide variety of surface conditions which result from the alternate freezing and thawing of snow cover in spring weather. This term is used in place of other terms when the usual surface descriptions cannot accurately or completely describe the situation, that is, when no single surface type covers at least 50% of the skiable surface of a trail.

Thin Cover - Indicates that the cover that currently exists will decline in quality due to skier traffic and may break through to the underlying trail surface. Thin Cover indicates that Bare Spots are anticipated to develop in the area during the day.

Variable - A wide variety of conditions which cannot accurately or completely be described using usual terminology, such as when no single surface type predominates.

Wet Granular - Loose or frozen granular snow which has become wet and soft after a thaw or from a rainfall.

Wet Powder - Powder snow that is wet when it falls (you can easily make a snowball) or dry powder that becomes wet as the temperature rises above freezing or is dampened by rain.

these explanations are commonly found in skiing handbooks and trailguides

Log in or register to write something here or to contact authors.