Radar Detects a Tornado North of Harpers Ferry Iowa With a Visible Debris Ball on Correlation Coefficient Scan as the Storm Moves Toward Lynxville and Crosses Into Wisconsin
A tornado has been detected on radar north of Harpers Ferry, Iowa and is actively moving to cross the river into Wisconsin. Radar imagery captured at 6:01 to 6:02 PM shows one of the clearest signs that a tornado is on the ground and causing destruction, a visible debris ball showing up on the correlation coefficient scan.
What the Radar Is Showing
Dual radar imagery from KARX and KILX shows two critical panels side by side that together paint a very clear and alarming picture:
Left Panel: Correlation Coefficient at 6:01 PM The most important feature on this scan is the stark blue debris ball clearly visible north of Harpers Ferry. A debris ball on radar occurs when a tornado is actively lofting large pieces of debris including trees, buildings, vehicles and soil high into the atmosphere. This is one of the most definitive radar confirmations that a tornado is on the ground and causing significant damage at that exact moment.
Right Panel: Velocity at 6:02 PM The velocity scan shows an extremely tight couplet of deep red and bright green colors in very close proximity to each other. Red indicates winds moving away from the radar while green indicates winds moving toward it. When these two colors appear this tightly together it confirms violent rotation at the core of this tornado.
Why This Tornado Surprised Forecasters
This tornado is occurring in an area that sits comparatively north in the risk zone, rated at only a Slight 2 out of 5 on today’s severe weather outlook. This is a critical reminder that tornadoes can and do occur outside the highest risk zones.
The reason this northern location is producing a tornado despite the lower risk rating is the left-most edge of the jet streak exit region, which is generating the strongest vertical motion in this part of the atmosphere and creating conditions capable of supporting significant tornado development even where the overall risk was considered lower.
The Storm Is Crossing Into Wisconsin
This tornado is tracking northward across the Mississippi River from Iowa into Wisconsin. Communities on the Wisconsin side of the river need to be on immediate high alert as this storm continues to move and strengthen.
Areas at risk include communities along and north of the Iowa and Wisconsin border near the Harpers Ferry and Lynxville crossing.
What the Debris Ball Means for People on the Ground
A debris ball on radar is not a prediction. It is not a possibility. It is real time confirmation that a tornado is actively destroying things on the ground right now. The debris being lofted into the atmosphere is physical material being ripped from the earth by the tornado’s violent winds.
If this storm is approaching your location you have no time to hesitate.
Take Shelter Immediately If You Are in the Path
- Get to the lowest floor of a sturdy building right now
- Move to an interior room away from all windows
- Do not go outside to look for the tornado
- Do not attempt to drive away from this storm
- If you are in a mobile home or vehicle get out immediately and find solid shelter
- Keep weather alerts active on your phone at all times
- Monitor live updates at NOAA Storm Prediction Center
This is a fast moving and dangerous situation. The debris ball on radar confirms this tornado is real and it is causing damage right now.
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