10 years after the big blowdown

Portaging through the blowdown (Photo courtesy US Forest Service)

This Saturday will mark the 10th anniversary of the massive blowdown storm of July 4, 1999. The storm was one of the most significant ecological events in the history of the Superior National Forest and the Boundary Waters Canoe Area Wilderness and will live on forever in the memories of many who love the BWCAW.

Sixty injuries, no fatalities

In the space of about a half hour, straight-line winds of up to 100 miles-per-hour flattened trees across about 377,000 acres of the BWCAW. Hitting on the evening of the Fourth of July, traditionally one of the busiest times in the Boundary Waters, it is an amazing fact that there were no fatalities. It took up to two weeks for search and rescue crews to check all 2,200 campsites in the Wilderness. Sixty people were injured, 20 of which were severe enough to need evacuation by floatplane.

A report issued by the Forest Service in 2002 about the storm and the agency’s response (PDF) explains how the storm developed:

A hot, muggy day shrouded northern Minnesota on July 4, 1999 with temperatures almost reaching 100°F. A cold front swept into the area. Typically this mix creates a thunderstorm, but on this day it created a storm so powerful it pulled down winds from 20,000 feet above the Earth’s surface. These sudden, straight-line winds or “derechos” were estimated at 80 to 100 miles per hour. Put into perspective, a 70-mile-per-hour wind can blow a semi-truck off the road.

Ecological tipping point

A map of the areas affected by the blowdown (Courtesy U.S. Forest Service)

The ecological effects of the blowdown are still being studied. The sudden obliteration of the forest canopy in many areas made way for the growth of many tree species besides the pines that the Boundary Waters is known for.

In a Minnesota Public Radio story about the blowdown anniversary, Friends advisory council member Dr. Lee Frelich of the University of Minnesota describes how and why these changes are happening:

Ecologist Lee Frelich said the evolution of the forest leaped ahead because of the blowdown.

Ten years ago, under the big old pines, another generation of trees was coming up, ready to take over as the pines slowly died off.

“In this case, the wind came and wiped out the old pine forest in a few minutes, and they were able to start taking over immediately because they were small seedlings on the forest floor,” Frelich said.

And he said they’re growing like mad. White cedar trees that usually only grow a few inches are growing two feet in a year. They’re no longer competing for nutrients with the big old pines, and they have plenty of sun.

A tinderbox

Lighting a prescribed burn (Photo courtesy U.S. Forest Service)

The swaths of dead trees, many of which were tinder dry from years of laying exposed to the sun but off the ground, also contributed to two large wild fires in 2006 and 2007, the Cavity Lake and Ham  Lake Fires near the Gunflint Trail.

In the years following the blowdown, the Forest Service performed several prescribed burns in the Wilderness to reduce the risk of wildfires spreading to areas outside the Boundary Waters. The fires did what they were supposed to, making fires in those areas much more manageable than in untreated areas. According to the Forest Service’s Bruce Anderson, quoted in an article about the anniversary in the Ely Timberjay, the differences are dramatic:

Untreated areas saw extensive damage, according to Anderson, and not just to vegetation. “Eighty-five percent of the organic layer of the soil was removed as well,” said Anderson. By contrast, about 50 percent of organic soils burned as a result of prescribed fire. Anderson said the difference is likely the result of timing. Wildfires tend to burn during extreme fire conditions, while the Forest Service typically uses prescribed fire only under more moderate conditions, when potential for devastating fire is less.

Prescribed burning also allowed the Forest Service to save patches of older trees, such as big pine along lakeshores or lowland cedar, that might otherwise have burned. “Close to 50-60 percent of big, shoreline trees survived our fuel treatments,” said Anderson. “With Cavity Lake, the vast majority burned up. Eagle nests can also usually be protected under prescribed conditions, while they were typically destroyed by wildfire.”

Witnessing history

The blowdown and its aftermath will live on as one of the most important events in the history of the region for decades, if not centuries. The stories of those who suddenly found themselves trapped on remote lakes, the portages clogged by deadfalls, are a stark reminder of what exactly it means to venture into the Wilderness.

It’s hard to travel through the Boundary Waters today and not come across evidence of the storm, not to mention the subsequent fires. These visible scars are ongoing reminders of the power of nature. Such perspective is one reason why so many people have always loved the wilderness canoe country. Ultimately, understanding the blowdown and its effects is a profound example of appreciating “untrammeled” wilderness, unaffected by humans.

Additional resources:

• The Superior National Forest’s “Storm Recovery” site has lots of images, maps, reports and other information and resources.

2 Comments

• David C. Marsh says:

  July 23, 2009 at 9:07 am

  see my prior comments

  Reply
• Brad Weber says:

  August 9, 2009 at 7:18 pm

  We hiked out of the BWCAW during this storm. It was eery, green, loud and scary. The trees were moving so much that it messed up your balance. Kind of like walking after you are on a boat.

  Reply