 Most weather fronts originate in the Pacific Ocean, and travel northeast toward the Cascade Mountains.As fronts approach the North Cascades, they are forced upward by the peaks of the Cascade Range (Orographic lift), causing them to drop their moisture in the form of rain or snowfall onto the Cascades.As a result, the west side of the North Cascades experiences high precipitation, especially during the winter months in the form of snowfall.