Atmospheric rivers periodically bring heavy surf, rain, strong winds, and flooding potential to the Pacific Northwest coast of the United States and western Canada. These long columns of warm, moisture-laden air originate over the ocean in subtropical regions. Because the atmospheric rivers that hit North America tend to originate near Hawaii, they are colloquially called a "pineapple express." When these rivers of wet air reach the West Coast, they often drop substantial amounts of rain and snow.
The true-color corrected reflectance image above from the VIIRS instrument aboard the NOAA-20 platform shows a swirling, comma-shaped band of clouds approaching the coast on November 12, 2026.