BWCAW Storm Damage Assessment On July 4, 1999, storms caused serious damage to nearly 400,000 acres (over 600 square miles) of forests in and around Minnesota's Boundary Waters Canoe Area Wilderness (BWCAW). A comparison of resource satellite images taken before and after the blowdown event lets us map the extent of the damage and estimate its severity. The interactive interface below allows you to zoom in on a satellite image of the blowdown area, with a color-coded damage legend overlaid on it. The image map also shows lake names, portage trails and campsites. The damage overlay was created by a mathematical comparison of "before" and "after" images obtained from the Thematic Mapper (TM) scanning instrument carried on the Landsat series of earth resource satellites. Use the "About" button for a fuller explanation of the satellite images and change detection techniques used in preparing this view of the BWCAW blowdown event. In some areas depiction of damage is obscured by cloud; new TM images available in 2000 will give a clearer view. Map Controls Cursor Action Zoom In Set Zoom Factor Times Toggle foreground/background on/off with keyboard "F" and "B" (place crosshair in map first) Use your left mouse button to drag a box in the map below, then click the "Apply" button to zoom in to the box you have defined. Alternatively, place a crosshair in the map by clicking on it, then click the "Apply" button to zoom in on that point. Overlay Legend Contents © 2001 Minnesota Department of Natural Resources. All rights reserved. Please send us your comments.