Weather Patterns of the Pacific Coast Rain and Snowfall Patterns

Water from the Sky

Topographic Lifting, Condensation, and Rainfall Clouds form anytime that moist air rises and cools below the dew point. As the water droplets get larger, some get so heavy, they fall to the sky as rain. If the temperature gets cold enough, it can fall as snow.

Rainshadow Effect Coastal rainforests Ocean Windward Drier intermountain trough Leeward Rainshadow Desert

Rainshadow Effect

Precipitation Map of Washington

Precipitation Patterns and Snow Pack O Cool Wet Winters and Warm Dry Summers Seattle, WAMoses Lake, WA Forks, WA

Rainshadow Effect Cross-Section

The Build Up of Winter Snowpack October Late November Late December Late March

The Summer Snowpack Meltout Early June Mid-JulyMid-AugustMid-October

Some snow fields will not melt completely in summer. Permanent Snow and Glaciers

The Movement of a Glacier Terminal Moraine Crevasses

This project was made possible in part by a grant from Washington’s National Park Fund.