Chinook Wind - The Chinook in The Pacific Northwest

The Chinook in The Pacific Northwest

The term Chinook wind is also used in British Columbia, and is the original usage, being rooted in the lore of coastal tribes and brought to Alberta by the fur-traders. Such winds are extremely wet and warm and come from the southwest, and are also known as the pineapple express, since they are of tropical origin, roughly from the area of Hawaii. The air associated with a west coast Chinook is stable; this minimizes wind gusts and often keeps winds light in sheltered areas. In exposed areas, fresh gales are frequent during a Chinook, but strong gale- or storm-force winds are uncommon (most of the region's stormy winds come when a fast 'westerly' jet stream lets air masses from temperate and subarctic latitudes clash).

When a Chinook comes in when an Arctic air mass is holding steady over the coast, the tropical dampness brought in suddenly cools, penetrating the frozen air and coming down in volumes of powder snow, sometimes to sea level. Snowfalls and the cold spells that spawned them only last a few days during a Chinook; as the warm Chinooks blow from the southwest, they push back east the cold Arctic air. The snow melts quickly and is gone within a week.

The effects on the interior of British Columbia when a Chinook is in effect are the reverse. In a rainy spell, most of the heavy moisture will be soaked out by the ramparts of mountains before the air mass reaches the Canyon and the Thompson River-Okanagan area. The effects are similar to those of an Alberta Chinook, though not to the same extreme, in part because the Okanagan is relatively warmer than the Prairies, and because of the additional number of precipitation-catching mountain ranges between Kelowna and Calgary. When the Chinook brings snow on the Coast during a period of coastal cold, bright but chilly weather in the interior will give way to a slushy melting of snow due to the warm spell more than because of rain.

The word is in common usage among local fishermen and people in communities along the British Columbia Coast. The term is also used in the Puget Sound area of Washington. It is important to note "Chinook" is not pronounced as it is east of the Cascades – shinook – but is in the original coastal pronunciation tshinook.

An outflow wind is more or less the opposite of BC/Pacific Northwest Chinook. These are called a squamish in certain areas, rooted in the direction of such winds coming down out of Howe Sound, home to the Skwxwu7mesh people, and in Alaska are called a williwaw. They consist of cold airstreams from the continental air mass pouring out of the interior plateau via certain river valleys and canyons penetrating the Coast Mountains towards the coast.