Sisi Fire

Perimeter mapped September 20, 2026 at 9:43 PM PDT, 3,908 acres (mixed methods). Point of origin 48.347, -120.831.

Live radar at the fire Forecast for Twisp

Size

3,908 acres

Containment

15%

Discovered

August 14, 2026 at 11:03 AM PDT

Cause

Natural

Location

10 Miles NW from Stehekin, WA

County

Chelan County

State

Washington

Protecting agency

USFS

Jurisdiction

USFS

Land ownership at origin

USFS

Personnel assigned

107

Incident management

Complex Incident Management Team, Type 1 Incident

Primary fuel

Closed Timber Litter

Estimated cost to date

$5,764,284

Incident type

Wildfire

Unique fire identifier

2026-WAOWF-260664

IRWIN identifier

DC4342D9-B479-44F1-906C-8ABD42E1F59C

Mapped area at the last perimeter of each day, from August 19, 2026 (1 acres) to September 21, 2026 (3,908 acres). The largest one-day growth was 561 acres, mapped August 28, 2026.

• Wind up to 12 mph from the west
• Relative humidity as low as 47%
• High of 55°F

National Weather Service hourly forecast for the fire’s point of origin, next 24 hours.

Full forecast for Twisp, WA

Red Flag Warnings and Fire Weather Watches covering the fire's point of origin.

No Red Flag Warning or Fire Weather Watch is in force at the fire.

NOAA’s Hazard Mapping System analysts drew heavy smoke over the fire’s origin in satellite imagery today (Mon, 8:00 AM PDT to Mon, 10:00 AM PDT).

NOAA’s smoke model forecasts near-surface smoke at the origin peaking at 5.3 µg/m³ around Tue, 7:00 AM PDT over the next 48 hours.

Smoke and fire layers on the radar

Posted on InciWeb, updated September 21, 2026.

The Sisi Fire is located in the Okanogan-Wenatchee National Forest within a remote, steep, and rugged mountainous landscape. The surrounding area consists of forested slopes, drainages, and variable terrain near the communities of Lucerne, Holden Village, and Stehekin. The fire is burning in a mosaic of timber, timber understory, brush, and partially cured grasses, with abundant snags and heavy dead and down fuels. Fire behavior remains active, including backing, flanking, uphill and up-drainage runs, group tree torching, and spotting. The greatest potential for growth remains along the southern and eastern portions of the fire where active heat, continuous fuels, and steep terrain align. The U.S. Forest Service initiated an aggressive initial attack on the Sisi Fire using a Type 1 helicopter and rappeler support following a mid-August lightning storm. Although aerial firefighters achieved early success, progress halted due to severe hazards, including tree torching and rolling debris on 50% slopes. These conditions forced crews to disengage for their own safety. Following four days of active suppression efforts, critical fire weather triggered significant growth on August 20. Little Giant Fire resources will continue to respond and strategize its containment. A full-suppression strategy is being utilized, with tactics focused on keeping the fire within the smallest practicable footprint while providing the highest probability of success and minimizing risk to firefighters and aviators. Values at risk include Lucerne, Holden Village, Stehekin, recreation resources, infrastructure, and other natural and cultural resources. The Pacific Crest Trail remains closed between the North Cascades National Park/Glacier Peak Wilderness boundary and High Bridge along the Agnes Creek portion of the trail. Updates on alerts on closures: Forest: Okanogan-Wenatchee National Forest | Alerts | Forest ServicePark: Fire Closures - North Cascades National Park (U.S. National Park Service)

Original at InciWeb

• Twisp, WA33 miles east of the fire’s origin
• Darrington, WA36 miles west of the fire’s origin
• Granite Falls, WA42 miles southeast of the fire’s origin
• Manson, WA45 miles southeast of the fire’s origin
• Chelan, WA51 miles southeast of the fire’s origin
• Brewster, WA51 miles east of the fire’s origin