Winds blowing off the glacier-capped mountains of southeast Alaska sweep down the canyon formed by the Copper River and gust over the warmer Gulf of Alaska. On October 29, 2009, the winds picked up fine glacial silt, sending a pale brown plume of dust over the ocean. The dust is visible along the elbow-shaped course of the Copper River, filling the valley between the bright white mountains with a blur of haze. Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite acquired this photo-like image of the event. Snow and dust are not the only evidence of glaciers in the image. Blue-green swirls in the Gulf of Alaska are probably from powder-fine sediment, ground by glaciers, that has washed into the ocean from the Copper River and other outlets.
The large image provided above is at MODIS’ maximum resolution of 250 meters per pixel. The image is available in additional resolutions from the MODIS Rapid Reponse System.
NASA Earth Observatory image courtesy Jeff Schmaltz, MODIS Rapid Response Team at NASA GSFC. Caption by Holli Riebeek.