chinooks

Chinooks are a type of warm, dry wind that occurs in the inland Pacific Northwest region of North America, particularly in the states of Washington and Oregon, as well as parts of British Columbia, Canada. The term "Chinook" originates from the Cree word *sho-nop*, meaning "snow eater," as these winds are known to rapidly melt snow and cause sudden temperature spikes.

Chinooks develop when warm air from the Pacific Ocean moves eastward over the coastal mountain ranges, such as the Cascade Range. As the air descends the leeward side of the mountains, it undergoes adiabatic warming, a process where the air compresses and heats up due to decreasing atmospheric pressure. This results in a dramatic increase in temperature, often rising by 10–20°C (18–36°F) within hours. The winds can reach speeds of 40–100 km/h (25–62 mph), though they are typically less intense.

Chinooks are most common during the winter and early spring months, when cold air masses are trapped inland, and the contrast between the warm Pacific air and the cold continental air is most pronounced. The sudden warming can cause rapid snowmelt, leading to localized flooding and avalanches. While often welcomed for their ability to clear snow from roads and infrastructure, Chinooks can also pose risks to vulnerable populations, such as those with respiratory conditions or those living in unstable housing.

The phenomenon is not unique to the Pacific Northwest; similar winds, such as the Santa Ana winds in California and the Föhn winds in Europe, occur in other mountainous regions around the world. Despite their occasional hazards, Chinooks play a significant role in the regional climate, influencing agriculture, transportation, and daily life in the affected areas.