Why was there no warning with Wednesday’s tornado

The view from KCRG-TV9's Pinpoint Doppler Radar on Wednesday, April 8, 2021, when a tornado...
The view from KCRG-TV9's Pinpoint Doppler Radar on Wednesday, April 8, 2021, when a tornado struck southwest Cedar Rapids.(KCRG-TV9 Staff)
Published: Apr. 8, 2021 at 3:18 PM CDT
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CEDAR RAPIDS, Iowa (KCRG) - Following the tornado that touched down in southwest Cedar Rapids Wednesday night, many people on social media have been asking: “Why wasn’t there a warning?”

There are several reasons this can happen, as we saw Wednesday night.

There are limits as to what Doppler Radar can see. As the radar beam travels away from the radar, the beam height increases due to the curvature of the Earth. In Wednesday’s case, the National Weather Service Doppler Radar tracking the storm and used to issue warnings is based in Davenport, some 75 miles away. The radar beam would not have examining the lowest 4,500 feet of the storm.

It also is possible that the brief tornado touched down and lifted between radar scans. Radars scan a 360-degree area, it takes time for a radar beam to make a complete sweep. In some cases, that can take as little as 60 seconds or as much as five minutes depending on the radar’s mode. On Wednesday evening, a 360-degree scan took several minutes to complete.

During severe weather coverage, you’ll often hear meteorologists refer to storm spotter reports. These trained spotters provide information based on visual observations that are then passed on to the National Weather Service, law enforcement, media and other agencies that help to track severe weather in real-time. The tornado Wednesday night came after dark and in a situation where storm spotters may not have been deployed.

Severe weather can happen at anytime - with little or no warning. Severe weather with no warning - as was the case Wednesday evening - generally is brief and produces damage to a small, hyperlocal area.

As always, stay alert to changing conditions when there is a threat for storms in your area.

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