Bear Mountain Fire

201748,058 acresAlaska

The Bear Mountain Fire burned 48,058 acres, about 75 square miles, across Yukon-Koyukuk Census Area. It began on July 9, 2017.

Watch how it happened

Bear Mountain Fire · 2017

How it happened

Watch it burn in the order satellites saw it, coloured by how severely each place burned.

About this replay

Date (UTC)—Historical replay

Burned so far—acres

High severity—of the area so far

Detections1,410satellite fire pixels

Fire milestones

Burn severityHigh, Moderate, Low, Unburned to low, Increased greenness

Burning nowAreas reached in the last half day of satellite passes

Washington, D.C., to scale61 square miles of land, drawn at the fire’s scale

Timing: NASA FIRMS satellite fire detections (1,128 VIIRS and 282 MODIS) inside the final perimeter; each place takes the time of its nearest detection, so the order is satellite-observed but interpolated between passes, roughly every 12 hours. Severity: Monitoring Trends in Burn Severity (USGS, U.S. Forest Service), mapped from Landsat after the fire.

How severely it burned

Burn severity inside the final perimeter, classified from Landsat images taken before and after the fire.

Map of burn severity across the Bear Mountain Fire

Burn severity by class
Severity	Share	Acres
Highmost vegetation consumed, soils altered	33%	16,051
Moderatemixed: many trees killed, some survive	27%	12,895
Lowsurface fire, most trees survive	15%	7,281
Unburned to lowislands inside the perimeter, little change	13%	6,368
Not mappedcloud, shadow or water in the satellite images	11%	5,443

33% of the area inside the perimeter burned at high severity, about 16,051 acres; 60% burned at moderate or high severity.

Monitoring Trends in Burn Severity (U.S. Geological Survey and USDA Forest Service). Classes come from the change in a Landsat burn index (dNBR) between images before and after the fire; acres are each class’s share of the fire’s mapped area.

Where it burned

Acres inside each county, measured from the satellite-mapped perimeter.

Acres burned by county

Yukon-Koyukuk Census Area	AK	48,086

Other large fires in Alaska in 2017

Campbell River Fire161,363 acres
White Mountain Creek Fire97,960 acres
Nowitna Fire53,691 acres
Boulder Creek Fire40,369 acres
Helmet Fire35,919 acres
Lois Creek Fire33,996 acres

Monitoring Trends in Burn Severity (USGS and U.S. Forest Service). Type recorded: Wildfire.