The Great Lakes set a new daily waterspout record

A new record number of waterspouts was reported over the Great Lakes on Oct. 7. An incredible 185 were seen that day in the wake of storm conditions, and were reported by the International Centre for Waterspout Research (ICWR). This number crushed the previous record of 82 from Oct. 1, 2020. The average number seen in a year is 225.

While tornadic waterspouts are associated with a tornado, non-tornadic waterspouts are vortexes that occur on large bodies of water, such as the Great Lakes, where land breezes cause them occur. The Oct. 7 waterspout record was the non-tornadic variety.

Waterspouts form when cold air from land moves over warmer water, resulting in a large temperature differential. The evolution of a waterspout begins when a light circle surrounded by a larger dark area appears on the surface of the water. A spiral pattern then develops with alternating light and dark bands radiating out from the dark spot. This develops into a ring of spray called a cascade around the dark spot, which is similar to the eye of a hurricane. The cascade then develops into a vortex, stretching from the water surface to the overhead clouds. The vortex can reach a few hundred metres in height. The final stage is when the vortex dissipates.

Are the Great Lakes in danger?

“The key thing is the lake temperature,” says Environment and Climate Change Canada (ECCC) meteorologist Geoff Coulson. “You get pockets of warmer water in the lake just along the surface.”

On Oct. 7, the breakdown of waterspout location by lake was 181 waterspouts on Lake Erie, two on Lake Huron, one on Lake Ontario, and one on Georgian Bay.

Wade Szilagyi, a meteorologist and the director of ICWR, explains that there are two reasons why more waterspouts are seen on Lake Erie compared to the other Great Lakes. Lake Erie is the shallowest of the Great Lakes and the warmest. Warm water is one of the factors contributing to waterspouts, and it’s a big one. Lake Erie’s geometry also contributes to waterspout formation. With the lake being elongated, convergent lines of clouds and showers form easily, which is where the waterspouts tend to form.

How will the Great Lakes be affected by climate change?

While scientists usually point the finger at global warming for new weather extremes, Szilagyi says that is not the case with the waterspout reports. He explains that the number of reports has increased because of more people living around the Great Lakes (to report any occurrences); improvements in cell phones and social media making it easier to report waterspouts; and forecasts from ICWR increasing awareness.

Is it possible that several people are reporting the same waterspout, and that could account for the record-high number? Not likely. “We follow a stringent vetting process. We consider location, time, and distances,” says Szilagyi. “For example, if five people see a waterspout off of Cleveland, but they are at different times, then they are different spouts. Or, if five people see waterspouts at the same time but the distance between observers is far enough away, then they are different spouts.”

Are Ontario cottages designed to protect against a tornado?