Was Canandaigua hit by a tornado?

Throughout Monday afternoon, Chief Meteorologist Eric Snitil was on-air to cover a Tornado Warning that included the city of Canandaigua. Shortly after that Warning, damage reports started coming into the newsroom. Damage ranged from poles snapped in half…

To toppled trees.

(Image courtesy Damon Fletcher, Jan Waxman and Andrea F.)

It begs the question, was this a tornado that caused this damage?

From Chief Meteorologist Eric Snitil:

“Maybe. I’ll tell you, from my vantage point covering the storm live, there was most definitely rotation evident on radar velocity. We use this tool to isolate parts of a storm where inbound and outbound winds exist. At times, they do so in a tight couplet indicating strong rotation within a storm. While the rotation was clear, I wouldn’t call it the cleanest signature. Canandaigua is not located particularly close to any radar sites. As such, we really don’t get a chance to sample lower parts of storms because the radar beam height increases with altitude. Put another way, by the time that beam travels to Canandaigua, it’s already high enough to overshoot the critical lower component of the storm. Because of this, it’s easier to find rotation because you’re higher up. But it doesn’t necessarily tell us much about whether that rotation exists on the surface (remember, many storms rotate and never produce tornadoes).”

“Photos and video I have seen of the storm at its peak demonstrate intense wind gusts. I have yet to see any compelling video clearly showcasing a tornado. This doesn’t mean it wasn’t one. If there was, it was likely rain-wrapped, short-lived and darn near impossible to capture on video. In cases like this, the designation of tornado vs. no tornado will come from an NWS storm survey team that will investigate the pattern of damage. There are ways to identify whether this damage was consistent with a brief tornado or damaging straight-line winds, like a microburst. I’ll note, even before the Tornado Warning was issued, that storm was demonstrating robust straight-line wind signatures. Whether that core tightened up to produce a tornado, to some extent, is a moot point. Damage is damage regardless of what caused it.”

HOW CAN YOU TELL THE DIFFERENCE? Microbursts, or straight-line winds tend to cause damage in a parallel or divergent pattern. Rain-cooled air comes crashing to the ground from the storm & expands outward, often in the same direction. You’ll often see trees lying in the same direction. A tornado, on the other hand, tends to result in damage patterns that are convergent and more chaotic. This is the result of turbulent wind changing directions within the circulation. Trees in this case will criss-cross each other in a convergent pattern.

We shall see if a storm survey confirms a tornado. If it did, we’re likely talking EF-0 or EF-1 based on the damage.

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