The only publicly accessible report for the Aspen Fire indicates the fire has bulled its way into the Kaiser Wilderness. The fire blew past newly established dozer lines strung along ridges. Hundreds of man and machine hours were spent forming these lines of defense but the fire has breached every one on its eastward march.
The fire has burned to the 8,200 ft. elevation according to relief maps. Timber line for the Sierra Nevada range is 10,500 ft.. Concentration of burnable vegetation diminishes exponentially as elevation increases. Eventually there is nothing to burn.
The Aspen Fire began near the 4,000 ft elevation. Few fires span elevation levels to this extent. Elevation disparity presents challenges for fire managers. While temperatures may be cooler at the higher elevations winds are more extreme and unpredictable. Additionally the Sierra Nevada mountain range is dangerous for aviators generally and as the fire moves further into protected Federal wilderness direct attack by fixed wing and helicopter is about the only option for direct attack.
Fire crews cutting fire lines at elevation are hampered as well. 2,000 firefighters are currently assigned to the Aspen Fire and as the fire establishes itself further at higher elevation they will follow it. Cutting fire lines in the higher elevations is a challenge for even the most fit firemen.
Containment today is estimated at 40% with no clear estimate on full containment. Containment is confined for the most part to the San Joaquin river drainage, the western fire boundary. At the current rate of spread and with predicted weather it looks like the Aspen Fire could burn through most of August.