I was mid-way travelling up the Basswood River when the wind/rain struck.  It was very hot and humid in the morning when I packed up camp and I remember wishing it would cloud up and rain a bit to cool off; also thought it was very unusual weather and "something" was going to blow up out of it.
As the weather was apparently getting worse I passed a group who had stopped on a campsite and put up their tarp for cover.  They warned me the weather was looking bad and I agreed but kept on paddling.  It started to rain, it had sprinkled off and on a bit prior, so I took refuge under some overhanging trees along a 20 foot cliff with its foot in the water, sitting in my kayak and thinking it would soon pass.
It began to rain hard and then pour.  I went from too hot to soaking wet and cold in a short while and then sat it out in the rain, finally having to bail my kayak while I sat in water, because I thought I would finally fill up and sink if I didn't.  It was windy but I had picked the lee side of the cliff and had a couple trees to hold on to so I didn't get blown out into the open so can't say it was much more than a thunderstorm where I was.  I think the group who had put up the tarp probably didn't stay dry under it.
When it passed I paddled to the nearest big rock on shore and unloaded my stuff and poured the excess water out of the kayak, then continued on soaking wet.  At the top of upper basswood falls I ran into a Boy Scout group who were setting up camp on one of the sites there, looking just as wet as I was.  I portaged past, saying "We're having fun now...".  They didn't look amused.  Thinking about it later I believe they may have been out in their canoes on the water at the time the wind was the worst.
I camped on the Canada island between the two falls and dried out before nightfall.  That night the second thunderstorm blew by in the distance and kept up the lightning and thunder for an hour or two.  I could just see the 4th of July fireworks flashes against the clouds, and hear the booms from them in the direction of Ely and then the storm followed and carried on the show for quite a while longer.
I still had no clue that the severe blow-down had happened until the next morning.  I headed out for Fall Lake and soon ran across an entire, fully grown Red Pine which had been torn off its ledge rock, roots and all, and was floating down Basswood Lake.  That was unusual.  Then passed a campsite, everything out on lines including the daily newspaper drying.  Two huge Red Pines had fallen in the center of the site, one on either side of the tent and not far away.  I asked the campers if those trees had fallen after they were set up and they said "yes".
Further on at the portage there were big Aspen fallen over the path, hung up on other trees, so you had to stoop or crawl under them with the gear to get by.  Someone had already been there with a chain saw and cut some, until their chain apparently got pinched in a tree and was left hanging in it, over the path.
When I got within cell phone range I called home and my husband just said "Thank God" when he heard my voice on the phone.
IC

I remember the July 4, 1999 blowdown well. I was on Kawnipi Lake in a 3 man Wenonah canoe with my 2 brothers fishing for walleye when the storm came right at us. The walleye action was "unbelieveable" before the storm hit. The skies began to darken and my one brother teaches science in a high school in Cary, North Carolina and he said that it looked like an F2 was approaching. well we paddled fast over to a small island about 200 yards away. The staightline winds were unlike anything we had ever seen. We had to tie the canoe to a couple of trees and we hunkered down  in low area behind some rocks ... the water in Kawnipi was blowing up out of the lake. I thought that it was a tornado ... it sounded like a frieght train going by. If I recall correctly it was over in a about 10 minutes. It was an unbelievable experience ...I thought we were goners for sure. We made it back to our base camp on Mckenzie Bay and there was no real apparent tree damage there. We surmised that the storm began around the Kawnipi area and headed towards Ely... but were unsure. A couple of days later we saw several airplanes in the air to the south, which was unusual. We didn't know that the winds caused so much damage until we portaged our way back to Prairie Portage and Canadian Border Outfiiters. We encountered many trees that had been cut by chain saws on our portages. CBO told us that they were hit hard. If i remember correctly they said the straight line winds were 7 miles wide by 12 miles long??? but I may memory may be off. I also was up in Kawnipi on a 10 day solo trip via kayak. I remember  travelling back thru Agnes to Prarie Portage and watching the the woods burn...it was crazy...walking on portages that were charred black. I remember the winds died down on my way back thru the cliffs of Agnes and I watched the underbrush beneath the tall pines burning. I ran into 2 firefighters who were waiting to get picked up by helicopter. They had cut down the several small trees and brush on a small island in Agnes. They were tired and needed a break and ready to go home. It has been interesting to see the many new trees that have sprung up after the big fire. It did'nt take too long for the forest to regenerate.

I have a guide friend who was camped on Kekekabic on the west end, and another who was camped on Eddy Lake.  As I remember, it was pretty rough stuff, but I'll try to get more details.

I was on Gibson Lake when I saw the approaching storm.  Figured it was a similar large thunderstorm blowing up as had the previous day at about the same time.  Pushed my crew to cross Gibson and take the Cattyman Falls portage.  At the end of the portage, we stopped for lunch, because there was no way I was going to be on Cattyman in a thunderstorm.

The Boy Scouts teach that in a thunderstorm, your group needs to spread out, as lightning can arc from person to person.  So as the lightning gets closer, I send everyone out into the woods.  All was fine until the trees started really cracking.  Thankfully, I got everyone huddled up together on the rocky portage as the trees started crashing down.  It certainly felt like the entire forest was coming down.

One thing I will never forget, but I seldom hear anyone esle echo, is the intense thunderstorm that night.  We were camped on Ima, and I remember that storm keeping me up for at least an hour of almost nonstop flash-boom nearby strikes with other trees falling in the night.  Did a lot of praying that night.

We saw the storm from Red Lake, Ontario. We had just completed our first WCPP trip. We could see a whopper of a storm to the south, but at the time we didn't realize just how far south it was. To be four hours north of it, and still see the tops, you knew it was huge. We were thankful we weren't in it. As we drove home, they were working on a couple of washouts in the Canuck highway, and as we drove south of Frostbite Falls, we could see tree damage along Hwy 53. It looked like they had already removed some trees that had been in the road. We didn't know what had happened until we got home and our wives filled us in on the storm. Of course, we voraciously learned all we could about it.

I watched the derecho from Ely- a solid sweep of line separating a white gray sky from a deep gray blue sky. In the middle of the sweep of line was sharp parabolic projection of the darkness- a strange and ominous sky. I watched the line move from east to west and realized that nose like point was probably passing over my house some 12 miles to the north west.
Then a wall of wind and dust blew up Sheridan (169) taking out the hanging banners and setting off car alarms- then a hard cold wind-driven rain.

My house is just past the crest of a ridge topped with a grove of mature jack pine- my drive was a tangle of downed trees, stacked two and three high- 3/4's of the tall Jack pines were snapped off. It took me 10 minutes to make my way up the 100 or so yards of drive and a good four hours with a chain saw before I could get the car up.

The house was untouched.

I was not there but went to check it out the following spring. My favorite lake, Kekekabic, seemed to me ground zero for the winds. I always hoped to read about the party camped in one particular campsite .The campsite in the center of section two was devastated except for the trees around the tent pad. I am a believer in prayer and felt that whoever camped there was too.

The storm

The derecho of July 4, 1999, blew down millions of trees within the Boundary Waters Canoe Area Wilderness, most in a line from Ely, Minnesota to the end of the Gunflint Trail. 477,000 acres of wilderness were affected, or a little more than 40% of the total area of the BWCAW. In some areas, such as around Ogishkemuncie and Seagull Lakes, nearly every mature tree was blown down.

Sixty people in the BWCAW were injured during the storm, and one person was killed when the victim drowned.

After the blowdown, the Superior National Forest concluded that the millions of dead trees increased the risk of an uncontrollable "catastrophic" wildfire. The Forest Service has created a plan to minimize this risk by reducing the downed fuels in and around the wilderness. Some areas outside of the wilderness, particularly along the Gunflint Trail, were salvage logged. Within the BWCAW, the Forest Service has begun a series of controlled burns to reduce forest fuels. These prescribed fires, including the Three Mile Island Fire and the South Seagull Fire, are part of a total of 75,000 acres, or about 16% of the blowdown, that will be intentionally burned.

While intentional burns seemingly further damage the forests, the Boundary Waters ecosystem has experienced relatively frequent forest fires for thousands of years, and it is adapted to thrive with such disturbance. For example, Jack pines require the heat of a fire to open their cones and release seeds, and white pines and red pines tolerate low-intensity ground fires that clear out competing vegetation. Unfortunately, high-intensity fires tend to burn any seed left in the soil, and will typically burn any organic matter in the soil itself. Forests that regenerate after such an event tend to be dominated by aspen and paper birch, as the seeds from these species are very lightweight and are transported long distances by the wind. This does not bode well for any return to the pine forests that so many people love and enjoy, at least in much of the blowdown area where fires tend to burn long and hot.

The first major wildfire within the blowdown occurred in August 2005, burning approximately 1400 acres north of Seagull Lake in the northeastern BWCA. The 32,000 acre Cavity Lake Fire burned very hot in the blowdown area in July and August, 2006.

The July 4, 1999 blowdown was not the first event of its kind in the BWCAW. Smaller blowdowns occured in September of 1992 and July of 1988.