The Horne Fire: How Lightning Set Off Isle Royale's Biggest Blaze Since 1948

Lightning struck Isle Royale several times in a storm on August 10, 2021, and one of the strikes started what became the island's most significant wildfire since 1948. The Horne Fire burned approximately 335 acres, the third largest wildfire in Isle Royale's recorded history, in a national park on an island in Lake Superior.

A dry summer

The summer of 2021 was warm and dry across the northern Midwest, with above-average temperatures and rainfall far below normal, which led to drought and spread several wildfires across the Lake Superior region. Isle Royale's isolation did not protect it. A general fire ban took effect on July 16 because of the drought and the fire danger. Then the August 10 storm set off several small fires on the island's northeastern end.

From small fire to blowup

The most significant started near the Duncan Bay/Tobin Harbor Portage Trail. At first it burned low and spread slowly, and on August 12 an incident commander from the National Park Service Midwest Regional Office took charge. Later in August, strong west winds pushed it up and over the Greenstone Ridge and it expanded significantly. After that blowup it was officially called the Horne Fire. Closure orders shut many trails, campgrounds and docks on the island's east side.

Suppression

Wildland firefighters from four agencies in five states came to help. Aircraft monitored the fire's size and spread, and a single-engine airtanker dropped water it scooped from Lake Superior. On the ground, crews made firelines, set backfires, monitored the fire and cleared defensible space around structures. By the end of August no structure had been damaged except an outhouse on Minong Island, where a separate lightning strike had lit a fire.

Containment

Rain eventually increased and fire activity fell, though the fire smoldered in some places in thick duff, the dense layer of organic matter on the forest floor. The park closed for the season on October 31, 2021, and the fire was inspected one last time before being left to die out over winter. In spring staff assessed the burn area. The fire was declared contained on June 6, 2022, and officially out on June 10, 2022.

What was left

The burned landscape. NPS photo.

The fire left only the remains of a dense boreal forest. Monument Rock, once hidden by vegetation, is again an icon of the ridge and is now visible from Hidden Lake. Before the fire, the trail to Lookout Louise ran past moss-covered boulders and lichen hanging from spruce and fir. Now it is lined with burned snags, bare boulders and a charred understory.

A living laboratory

The park calls wildfire an agent of necessary change, and fire ecology is the study of fire's role in an ecosystem. At the burn, Isle Royale's ecologists now have a place to study how fire, living things and an island environment relate. In 2022 researchers began watching for invasive species and surveyed for new moose exclosures, fenced plots built to study how moose browsing affects vegetation in a burn area.

Over three years, artist Matt Kania studied the burn area through painting. His exhibit, After the Burn: Beauty and Renewal on Isle Royale, includes 24 plein air and 7 studio oil paintings and drawings of the visible scars of the fire and the plants growing back.

Sources

• National Park Service, Isle Royale National Park, 2021 Horne Fire on Isle Royale; rewritten in hubnx's own words. The page gives two dates for the day the fire blew up, so neither is stated here.