[5] The Sheep Fire near Susanville was originally included as part of the North Complex,[6] but on September 5, it was assigned to a separate incident.

[9] The fire originated along Claremont Creek, a tributary of the Middle Fork just south of Quincy, and quickly jumped the ridge northwards towards American Valley.

[5] On August 23, aided by high winds, the fire began advancing rapidly east forcing Spring Garden and Greenhorn to be evacuated.

[13] On August 30 crews conducted backfire operations on the eastern side of the fire and prevented it from spreading towards Spring Garden and Cromberg.

[15] On September 5, with fire activity much lower on the eastern sides, evacuation orders were lifted for Spring Garden, Greenhorn, Sloat and Cromberg.

[26] The southern boundary of the fire was mostly held along the Middle Fork, and crews worked to build secondary containment lines south of the river.

On the morning of September 8 a dry cold front moved in, bringing strong northeast winds and threatening the incomplete containment line along the river.

At 11:00 p.m. PDT, Kelly Ridge and Copley Hills, near Lake Oroville, were evacuated, as officials predicted strong winds would lead to continuing extreme fire behavior.

Daniel Swain, a climate scientist at University of California Los Angeles, compared the explosive wind-driven spread with the 2018 Camp Fire, which occurred just north of this area.

[47] By September 11, winds had shifted to the southwest, blowing the fire front and smoke back over the burn area and towards Quincy.

Fire activity was significantly decreased from the previous day, allowing crews to work on containment lines protecting homes around Bucks Lake and Little Grass Valley Reservoir.

[50] On September 15 continued southwest winds caused the fire to jump containment lines near Red Mountain, moving northeast towards Bucks Lake.

[52] On the morning of September 17, evacuation orders were issued for Meadow Valley and Tollgate as fire activity continued to pick up on the north side.

[55] On September 27, strong sustained winds picked up once again, starting spot fires outside of containment lines, including one on French Hotel Creek.

[56] An evacuation order was issued for Pulga, Concow, Big Bend and Yankee Hill as the fire moved west towards the North Fork Feather River Canyon.

[57] By the morning of September 29, the fire was within a few hundred yards of Highway 70, which was closed between Greenville Wye (west of Quincy) and Cherokee Road (east of Oroville).

[63] The death toll was temporarily lowered from ten to nine people on September 11 after a skeleton discovered in a burned storage shed was determined to have been an anatomical model belonging to an anthropology student, and not that of a victim.

[64][65] The Butte County Sheriff's office announced the discovery of three more sets of remains on Saturday, September 12, with thirteen still missing.

[68] The death toll remained at fifteen until October 28, 2020, when the Butte County Sheriff's Office announced that a 54-year-old male resident of Berry Creek had passed away from lingering burn injuries one week prior.

Doug LaMalfa, the House representative for California's 1st district, criticized Newsom's "audacity to come tour the North Complex and peddle his climate change agenda while offering zero solutions to alleviate the pain of our people or get these fires under control".

State senator Jim Nielsen and assemblyman James Gallagher issued a press release calling Newsom's comments a deflection from "the fundamental failure to address the fuels build-up in our forests that are the cause of these devastating fires".