Snowfall is extremely low in Arctic Alaska, among the highest in the world
in the southern coastal mountains, and moderate in the regions between.
Snowfall in the coastal mountain ranges provides the source of supply for
the snowfields and glaciers that cover about 34,000 square miles of the
state. Thompson Pass (near Valdez) has recorded up to 225 inches in a
single month.
On the north and west coasts, snowfall is light to moderate, but the winds
continuously rework the snow into drifts. In the Interior, low-speed
winter winds, combined with forest cover, leaves snow relatively
undisturbed after it falls. In both areas winter thawing is rare and snow,
once fallen, tends to persist until spring. South of the Alaska Range,
winter thaws often melt the snow on the ground, and snow that falls along
the coast seldom remains more than a few weeks. These patterns are
shifting with climate change.
The average density of freshly fallen snow is about 0.10 but varies
greatly by region and season. Older snow varies due to differences in
temperature, wind conditions, drifting, packing due to snow load above,
and recrystallization