Lightning and the Lake, A Striking Look at Our Summer Storms

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The most likely time to spot lightning on Lake Superior is between the third week of June and the second week of August, says Matt Zika, warning coordination meteorologist at the National Weather Service station in Marquette. But even during those hot-summer weeks, you’re not going to be seeing as much T-storm activity as above land-bound prairies.

The photographers who took these images were in the right places at the right times (and, we assume, took the right precautions to be safe).

Lake Superior, chillier than the air in summer, inhibits development of storms over the Lake, unlike the lake-affected winter, fall and spring months when the warmer-than-air water can act as a storm generator. This means that our Lake region actually endures thunderstorms less frequently than other parts of the U.S. and Canadian Midwest.

“It’s rare to get storms that are just going to develop on their own over the Lake,” Matt explains. “Thunderstorms need rising updrafts … to grow and form. Because the Lake stays as cool as it does, it’s very rare to get updrafts.”

What does generate thunder boomers here are the organized systems of storms sprouted in Canada. Once a system reaches it, Lake Superior can act as a damper or an enhancer, Matt says. “Sometimes when we have a surge or organized cluster, as it moves out across the Lake that cold pool of air allows that surge of wind to increase and intensify. … Other times as storms move out over the Lake, they dissipate. The bigger the cluster, the more likely the storms will maintain themselves.”

the myth in the Lake Superior neighborhood is that while hurricane-force winter blizzards may arrive, most dangerous summer tempests do not.

“So many people think that we’re totally safe from severe thunderstorms and tornadoes. That’s partly true, but mainly false,” says Carol Christenson, warning coordination meteorologist at Duluth’s National Weather Service station.

As Matt explained, thunderstorms do tend to weaken when they approach the Lake, but the Lake area was not immune during a 1969 northern Minnesota tornado outbreak that stretched from near Brainerd to Lake Superior, killing 15 people including two in Two Harbors.

“We do ask that you stay away from the windows,” Carol says. “You’re still not totally safe even in your home.”

The most recent lightning-related tragedy on Lake Superior was in 2012, when a family had come ashore in their boat at Duluth’s Minnesota Point during a storm to seek shelter on land. Sudden hail drove them back to their boat just as lightning struck, fatally injuring a 9-year-old boy.

Carol, who does skywarn training for weather spotters, recounts that she was once asked this conundrum: If I’m on the lake in my aluminum fishing boat during a thunderstorm, is it safer for me to jump into the water or to stay in my boat?

The answer: It’s safer if you are off the water all together and the sooner the better. (Can you swim faster than you can boat?). Sailboats often have lightning conductors or “air terminals.”

The water of the Big Lake, like all lakes and like your bathtub, can conduct electricity outward, whatever the source, even from a lightning strike. The Lake mimics a flat land surface, and, as we know, the tallest point in a thunderstorm may attract the lightning. So you don’t want to be the tallest point on the Lake. Lightning, by the way, can travel at about 220,000 mph, heat to 50,000° F and pack an electric punch of 30,000 amps or 300 million volts. (Your house electrical outlet nets 15 amps and about 120 volts.)

Thunder, in case you were wondering, travels a mere 750 mph, so don’t wait to hear the crack to find a safe spot.