Smoke from scores of fires flows like a river through the skies over eastern Alaska (roughly the western two-thirds of this image) and western Canada (eastern third) on June 27, 2004. The region has been experiencing extreme fire activity since mid-June, as a result of record-breaking lightning activity and unforgiving weather. The fires are so smoky it is difficult to gain perspective in the image, which was captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite. At top, to the right of center, ice is visible in the Beauford Sea, while at bottom center, the Gulf of Alaska peeks through clouds. The Yukon River flows westward out of the image at left. Areas where MODIS detected active fires are marked in red.