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Two summers ago, a strong storm devastated parts of Coleharbor. Many people wondered what caused the damage? In this week's Weather Extra Hutch and Ryan talk with the National Weather Service about how to tell the difference. Ryan - Today our topic of discussion is going to be how do we know whether a Tornado has damaged something or if it's been straight line wind damage. Hutch - During the daylight hours if you've been in a tornado and in a lot of cases people witness these but sometimes people don't actually see what caused the damage, they just walk outside and know there is a whole lot of damage. Obviously tornadoes can cause significant damage, but so can straight line winds in excess of 100 MPH such as the Cole Harbor storm of last year. (J.P. Martin/Bismarck NWS Meteorologist) the most difficult assessment I've had in my career has been Cole Harbor and we determined that was not a tornado at Cole Harbor it was straight line winds. Based on the damage throughout the city most of the city had damage, there was no path leading into Cole Harbor, going through Cole Harbor or coming out the other side. Ryan - The way that they determined it was straight line winds was by looking at the debris...in this graphic all of these trees are blown over from the left side to the right side so we can determine that it was not a tornado, it was straight line winds. Hutch - on the otherhand if a tornado had went through that same grove of trees we may see damage that looks like this where the trees are laying down but in different directions. Ryan - exactly Hutch, like in this footage we have from Northwood you can see the debris is scattered everywhere, not just in one direction. Hutch - Once it was determined that a tornado did indeed cause the damage then the job of the meteorologist becomes how strong was the tornado and that's where the F-scale comes into play. we can determine how strong the winds might have been if we have a few clues as to the type of construction of the damaged building or maybe for instance how far the combine was thrown. Sometimes tornadoes do not hit cities or vehicles or buildings and travel through the prairies of North Dakota. J.P. Martin - If you think about it a tornado going through a Corn field a zero or and five would pretty much do about the same damage in otherwords the corn would be completely stripped off of that field. So to determine well was it a zero or a five would be nearly impossible. If you have a question or a crazy idea for a weather extra segment log on to www.kxnet.com/weatherextra and send an e-mail to weather12@kxnet.com