Yukon Flats 26 Fire

1991122,822 acresAlaska

The Yukon Flats 26 Fire burned 122,822 acres, about 192 square miles, across Yukon-Koyukuk Census Area. It began on June 30, 1991.

Watch how it happened

Yukon Flats 26 Fire · 1991

How it happened

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

About this replay
IgnitionJune 30, 1991Historical replay — order not recorded
Final area122,822 ac
Revealed—
Counties1

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 Yukon Flats 26 Fire
Burn severity by class
SeverityShareAcres
Highmost vegetation consumed, soils altered6.8%8,297
Moderatemixed: many trees killed, some survive23%28,071
Lowsurface fire, most trees survive39%47,731
Unburned to lowislands inside the perimeter, little change26%31,907
Increased greennessvegetation greener after the fire than before3.6%4,421
Not mappedcloud, shadow or water in the satellite images2.0%2,395

7% of the area inside the perimeter burned at high severity, about 8,297 acres; 30% 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 AreaAK122,896

Other large fires in Alaska in 1991

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