(WKYT)For today’s Good Question, Mike asks, “How does the National Weather Service determine if storm damage is from straight-line winds or a tornado?”
You may see video of what looks like a tornado, but until the National Weather Service confirms it, it does not go in the record books.
Meteorologists first identify possible tornadoes through rotation signatures on radar. If you watched storm coverage recently, you may have seen meteorologists point those out during live broadcasts.
Then comes the ground survey
After a storm, the NWS sends teams into areas where damage was reported. Those teams look for specific physical markers that help distinguish one wind type from another.
In the case of a tornado, investigators look for evidence of rotation along the damage path. Projectiles — objects carried and launched by the storm — are a key indicator. They may be found embedded in the ground or lodged in nearby structures, and investigators can often trace them back to their point of origin to help map the tornado’s path.
Aerial views fill in the gaps
Survey teams also collect video and photos from the air. An aerial perspective can reveal a damage path that may not be visible at ground level.
Direction of damage is the biggest indicator
The direction debris and damage travel is the most telling clue, according to the NWS.
- Straight-line winds push everything in one direction.
- Microbursts push damage outward from a central point.
- Tornadoes cause damage that converges toward a central path.
Witnesses round out the picture
Physical evidence alone does not close the case. NWS investigators also talk to witnesses, then combine all of that information before making a final assessment.
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