Localsnow.org brings together many
resources to help plan your forthcoming mountain outing. The Pacific
Northwest has the most accessible ski and snowboard facilities
in North America. From British Columbia to the Cascades of Washington and Oregon,
and the Sierra of California. We get the weather, so we get the snow.
It is now understood that the prevailing jet stream moves onto the North American
continent predominantly via the Pacific Northwest. This air arrives from
the arctic and north pacific ocean cooled by ice and sea yet carrying plenty of moisture.
The inevitable consequence is orogenic precipitation as the air mass rides
up over the mountains, cools, and can no longer retain its moisture.
In the winter, this means mountain snow. If by chance the jet stream
is diverted to the south, then the Sierra Nevada of California may receive this precipitation.
If the upper air winds of the jet stream pass through the more tropical latitudes of
the Pacific Ocean, say off of Hawaii, that warm air picks up as much moisture as its
temperature will allow. Often in the Fall, this warm, moist air pummels the entire
west coast as heavy rain. Later, as ski areas accumulate 3-4 storms worth of snow our winter
season starts, typically with 30 inches of snow base. By April, we may have had
30 or more storms and hundreds of inches of snow.