As a young assistant professor of physics at a university in Japan, T.T. Fujita was sent to the nuclear bomb blast sites at Hiroshima and Nagasaki. There he was to analyze the damage inflicted onto the buildings and determine the height above the ground of the bomb detonation. The explosive force of the bombs spread downward, hitting the ground and then spreading out in all directions. That morbid but scientific task would eventually lead Fujita to become a household name in the United States some 30 years later. Well, if not a household name at least he would become a household letter.

Labor Day late afternoon 2002 in Wisconsin and a tornado rips through the town of Ladysmith. We hear the news reports and see the pictures of devastation. And then the next day we hear the assessment: it was an F-3 tornado at its worst point, downtown on Highway 8 by the Baptist Church. It then weakened somewhat to an F-2 and finally an F-1 well outside of town before lifting back into the clouds. The letter F stands for the Fujita damage scale and the assessment of damage was performed by the Warning Coordinating Meteorologist (WCM) at the local National Weather Office.

Professor Ted Fujita came to the United States and the University of Chicago to study thunderstorms and their related fury. That included damaging winds and tornadoes. After a huge outbreak of tornadoes on Palm Sunday 1965, when twisters pounded the Midwest and Ohio Valley, Fujita took to the air and surveyed the damage from 2,000 feet above the ground. He took copious photos and soon discovered the link between what he saw in 1965 with what he earlier witnessed as a younger man in Japan in 1945. He applied a damage scale that would relate the extent of the destruction to the estimated wind speed of the tornado. The Fujita Scale was born. The Ladysmith F-3 damage was consistent with wind speeds between 158 and 206 miles per hour.

After tornado or wind damage occurs, the WCM from a local National Weather Service office visits the damaged area and determines if it was struck by a tornado or downburst (microburst) winds. A downburst occurs from beneath a thunderstorm when a downrush of air strikes the ground and spreads out in all directions. Fujita coined this term and discovered this phenomenon because of what he saw at Hiroshima and Nagasaki. Microbursts cover an area less than two and a half miles across and can produce a wind well over 100 miles per hour. Microburst damage tends to look "flattened" while tornado damage looks more "twisted". The damage is a product of the type of wind and it is up to the WCM to determine this. Much of the damage from a microburst looks like tornado damage to the untrained eye, and many people have trouble believing that the damage in their neighborhood was not a tornado. But microburst damage is common, tornado damage more rare.

The WCM must take into account building materials and structure types when assessing wind damage. A weakly fortified structure will crumble under a moderately strong wind. When huge pick-up trucks and rail cars are seen tossed about by the wind, then the WCM knows it was a powerful force. The Fujita scale goes from the weakest tornado and light damage of F-0 (Up to 72 mph) all the way up to F-5 (incredible damage and wind speed above 261mph). Only two percent of all tornadoes are F-5 yet they cause the most deaths.

One note about the Ladysmith tornado that seems to happen with every damaging twister: witnesses say they heard no warning and that the storm came out of nowhere. Did you ever notice that there is never any warning? In fact there is almost always a severe thunderstorm warning in effect and often a severe thunderstorm watch or tornado watch has been in effect in the area for several hours. Many people still don't know the difference between the various watches and warnings and aren't sure where they can hear such information. In the case of Ladysmith, a severe thunderstorm warning was in effect and as the National Weather Service clearly states in its warnings, severe thunderstorms can and do produce tornadoes.

The bottom line is there were no fatalities in Ladysmith, a minor miracle considering the tornado ripped right through the town. But there was a huge squall line of storms approaching and the western horizon looked black and ominous. So be an informed person when it comes to severe weather. Get a NOAA Weather Radio to alert you to watches or warnings in your area, and when a warning is in effect keep an eye to the sky. It will reduce the chances of surprises.