Winds approaching 100 mph caused extensive tree damage at the intersection of WI-32 and WI-64 north of Mountain, Wis. (Tony Dello/@Wx_TD)

Quince Mountain was having a relatively normal Friday morning in Wisconsin. By lunchtime, he found himself preparing as if for a hurricane.

“I got a message from a friend of mine who’s a meteorologist,” Mountain recalls. “She told me what was coming, and immediately my wife and I started planning.”

At the Storm Prediction Center in Norman, Okla., meteorologists were equally concerned. By sunrise, it had declared a rare moderate risk for severe weather mentioning the potential for “widespread damaging winds, some hurricane force.” Mountain’s mind immediately flashed back to a storm in 2007, which had caused extensive damage in northern Wisconsin. “My wife decided to stay home with the dogs, while I headed to a funeral out of town.”

Around sunset, the storms struck. “I think people expect a storm to come in and build gradually,” Mountain said. “This was a wall of wind.”

National Weather Service radar showed the bow-shaped line of storms pummeling northern Wisconsin. Known as a “derecho,” these wind storms start innocuously on hot, humid days but feed on the steamy air and can grow into monsters.

Derechos are known for moving along at breakneck speeds and their extreme wind gusts, which can top 90 mph. Friday night’s system over the Upper Midwest surged east at 60 mph, conditions abruptly pivoting from calm to chaos in mere seconds.

“When the storm hit, it hit hard,” says Mountain’s wife, Blair Braverman. “I had been planning to do one more round to check on things, but the wind and rain came so quickly that I could barely leave the porch.” She grabbed a flashlight and ran to the basement, the power out by the time she reached the bottom stair. After a furious half-hour or so, the winds abated. But they left a mark.


A swath of felled trees near White Lake, Wis., in the wake of last week's derechos. Wind gusts in this area were estimated to 100 mph. (Planet Labs) (Planet Labs Inc/Planet Labs Inc)

The National Weather Service in Green Bay announced the damage had been caused by a macroburst. Macrobursts are massive downbursts of wind that originate from the cloud and slam to the ground, typically covering a zone 2.5 miles across or wider. But spawned by the derecho, this macroburst was bigger. Much bigger. Fifteen miles wide, in fact. Preliminary data suggests the 100 mph winds may have affected this zone.

Phil Kurimski, a senior meteorologist at the National Weather Service office in Green Bay, described the resulting damage as “widespread.”

“From what we’ve seen, we’re talking a very large area of intense wind damage,” Kurimski said. “We’ve seen some footage from drones and flyovers. Now we’re trying to determine if there may have been tornadoes within that.” So far, three have been confirmed.


A derecho forms a backward-c shape in Wisconsin as it "bows out." Winds of 100 mph accompanied the vicious line of storms as the powerful "bookend vortex" blasted through. (Matthew Cappucci/GR2 Analyst)

"I could show you two or three dozen damaged cottages within a few miles of me, and I’m not even at the worst of it,” Mountain said. Mountain and Braverman still are without power, and “there’s an unmarked power line on the ground” near their house.

The worst damage occurred in Langlade and Oconto counties, where the National Weather Service reports that “many tens of thousands of trees were snapped or uprooted.”

Friday’s storms initiated in Minnesota around lunchtime, quickly becoming worrisome by late afternoon. After terrorizing northern Wisconsin around nightfall, they slid east over Lake Michigan, causing damage Saturday morning in Michigan itself. By then, another derecho was brewing in South Dakota, sweeping east across Minnesota and into the same hard-hit areas of Wisconsin.

By Sunday morning, more than a half-million customers were without power in Wisconsin and Michigan from the derecho double whammy.

Steve Beylon is the chief meteorologist at WBAY-TV in Green Bay. He described the scale of the damage as “extremely impressive.”

“I can’t recall such a widespread 1-2 punch of severe weather in my 13 years here,” Beylon wrote. “Tens of thousands of trees have been uprooted. 100 mph winds in a heavily forested area will leave people disoriented with few landmarks to go by.” He said that covering the storms was an experience that will last with him “a long time.”

Amid the damage, Braverman isn’t discouraged. Instead, she says the storms have brought out people’s best.

“Everyone’s helping each other, figuring out where to get generators, pitching in with chain saws, and lending out camping equipment. Wisconsinites are tough.”