5. A total of 1 million acres (4,000 km²) of forest were damaged or destroyed, and the storm caused a total of $30M damage (1977 dollars). Bow Echo discovered After the storm, Dr. T. Theodore Fujita became aware of the extreme wind damage over northern Wisconsin and decided to conduct an investigation. He noticed that there were three areas of extreme damage from northeastern Minnesota to extreme northwestern Wisconsin, and then two more areas of forest blowdowns extending from Hayward to Rhinelander. He then went back and looked at the radar echos, and he noticed that they evolved into a bow signature. It was during this investigation that Dr Fujita discovered the bow or spearhead radar echo. See also List of derecho events References External links NOAA page on the Independence Day Derecho of 1977 1977 meteorology 1977 natural disasters in the United States Derechos in the United States Natural disasters in Wisconsin Natural disasters in Michigan July 1977 events in the United States 1977 in Wisconsin 1977 in Michigan