Hsl Nnw 37 Fire
199127,142 acresAlaska
The Hsl Nnw 37 Fire burned 27,142 acres, about 42 square miles, across 2 counties. It began on June 23, 1991.
Watch how it happenedHsl Nnw 37 Fire · 1991
How it happened
See how severely each place burned, revealed outward from where it started.
How severely it burned
Burn severity inside the final perimeter, classified from Landsat images taken before and after the fire.

| Severity | Share | Acres |
|---|---|---|
| Highmost vegetation consumed, soils altered | 21% | 5,627 |
| Moderatemixed: many trees killed, some survive | 47% | 12,666 |
| Lowsurface fire, most trees survive | 17% | 4,727 |
| Unburned to lowislands inside the perimeter, little change | 10% | 2,835 |
| Increased greennessvegetation greener after the fire than before | 0.5% | 126 |
| Not mappedcloud, shadow or water in the satellite images | 4.3% | 1,161 |
21% of the area inside the perimeter burned at high severity, about 5,627 acres; 67% 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.
| Yukon-Koyukuk Census Area | AK | 21,160 |
| Northwest Arctic Borough | AK | 5,994 |
Other large fires in Alaska in 1991
- Yukon Flats 26 Fire122,822 acres
- 131569 Fire109,499 acres
- Btt S 17 Fire43,568 acres
- Btt W 64 Fire35,602 acres
- 131655 Fire30,237 acres
Monitoring Trends in Burn Severity (USGS and U.S. Forest Service). Type recorded: Wildfire.