Btt W 64 Fire

199135,602 acresAlaska

The Btt W 64 Fire burned 35,602 acres, about 56 square miles, across 2 counties. It began on July 1, 1991.

Watch how it happened

Btt W 64 Fire · 1991

How it happened

See how severely each place burned, revealed outward from where it started.

About this replay
IgnitionJuly 1, 1991Historical replay — order not recorded
Final area35,602 ac
Revealed—
Counties2

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 Btt W 64 Fire
Burn severity by class
SeverityShareAcres
Highmost vegetation consumed, soils altered19%6,773
Moderatemixed: many trees killed, some survive47%16,812
Lowsurface fire, most trees survive20%7,052
Unburned to lowislands inside the perimeter, little change9.9%3,532
Not mappedcloud, shadow or water in the satellite images4.0%1,422

19% of the area inside the perimeter burned at high severity, about 6,773 acres; 66% 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
Northwest Arctic BoroughAK34,158
Yukon-Koyukuk Census AreaAK1,465

Other large fires in Alaska in 1991

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