The fire caused the closure of the North Cascades Highway (State Route 20) and evacuations of recreational facilities and three Seattle City Light hydroelectric dams in the area.

[2][3] The fire grew to over 1,440 acres (580 ha) by August 4 and prompted the immediate closure of the North Cascades Highway (State Route 20) between Newhalem and Rainy Pass.

The strategy was paused after a red flag warning was issued by the National Weather Service for the Diablo area with a high temperature of 104 °F (40 °C) recorded on August 13.

[17] Smoke from the fire moved southwest into the Puget Sound region, including Seattle, on August 13 and caused worsened air quality readings.

[19] The North Cascades Highway reopened on August 23 for through travelers, with stops prohibited and recreation areas remaining closed due to the Sourdough and Blue Lake fires.