As fronts approach, they are forced upward by the peaks of the Olympic Range, causing them to drop their moisture in the form of rain or snowfall (Orographic lift). As a result, the Olympics experience high precipitation, especially during the winter months. During winter months, weather is usually cloudy, but, due to high pressure systems over the Pacific Ocean that intensify during summer months, there is often little or no cloud cover during the summer. Because of maritime influence, snow tends to be wet and heavy, resulting in avalanche danger. Precipitation runoff from the mountain drains into the Hamma Hamma River and Skokomish River.