Justin Poublon is a meteorologist and storm chaser from Wisconsin who witnessed a meteotsunami on July 27, 2026. This rare video shows large waves piling up on shore of Lake Winnebago after the Menasha tornado struck.

Meteotsunami hits Lake Winnebago after Wisconsin tornado

On July 27, 2026, a tornado struck the Fox Valley area of Wisconsin, destroying a wide swath of the city of Menasha. The tornado also triggered a meteotsunami in neighboring Lake Winnebago. What’s a meteotsunami? A meteotsunami is when a meteorological event causes large waves in a body of water. NOAA says:

Meteotsunamis have characteristics similar to earthquake-generated tsunamis, but they are caused by air-pressure disturbances often associated with fast-moving weather systems, such as squall lines. These disturbances can generate waves in the ocean that travel at the same speed as the overhead weather system.

Development of a meteotsunami depends on several factors, such as the intensity, direction, and speed of the air pressure as it travels over a waterbody. Like an earthquake-generated tsunami, a meteotsunami affects the entire water column and may become dangerous when it hits shallow water, which causes it to slow down and increase in height and intensity. Semi-enclosed water bodies like harbors, inlets and bays can greatly intensify a meteotsunami.

The meteotsunami in the Fox Valley did not cause any destruction. It was a rare phenomenon that resulted from the strong tornadic winds.

A first-hand account

Justin Poublon, a meteorologist and storm chaser from Wisconsin, described his experience:

While the Appleton/Menasha tornado was occurring, Lake Winnebago appeared to drop by 1 to 2 feet at my location near Adella Beach/ Neenah, Wisconsin. At 12:29 – likely after the tornado had ended – I observed an unnaturally long wave approaching from the northeast as the water rushed back into the bay. I moved my vehicle multiple times to stay clear of the rising water, which spilled over the bank. I observed flying/falling debris such as shingles, small sticks and a projectile plastic kiddie pool as part of the broader event.

Bottom line: A meteotsunami is an event that occurs when a weather system causes waves on a body of water to pile up on shore. On July 27, 2026, a tornado spawned a meteotsunami on Lake Winnebago.