To say the Bootleg Fire in Southern Oregon was active Wednesday is an understatement. It exhibited extreme fire behavior for hours as winds out of the southwest and west gusted at 15 to 23 mph from 11 a.m. until 10 p.m. while the relative humidity was in the low teens.
I have never seen anything like the satellite photo below. The orange colors are a representation of heat from the very active fire. The eastern two-thirds of Oregon are covered in smoke and a large dark gray oval plume is east of the Bootleg Fire. The white plume stretching to the east appears to be a very, very large pyrocumulus cloud — condensation after the smoke has reached a high altitude. The very unusual feature is the sheer size of the pyrocumulus, which is about 130 miles long.
The fire was mapped at 10:14 p.m. Wednesday at 232,760 acres.
Wednesday evening the Safety Officer and Incident Meteorologist assigned to the Bootleg Fire took the unusual step of issuing a special weather statement to firefighters:
At 8:18 PM PDT, Doppler radar and GOES West Satellite was tracking a pyrocumulonimbus over the Bootleg Fire. Preliminary indications are showing that the smoke plume could possibly collapse over the next hour. Although confidence in the collapse is low, this would be a serious event with strong and quickly shifting winds. Winds in excess of 40 mph will be possible with this collapse. Firefighters and all other persons in and around the Bootleg Fire should prepare for DANGEROUS WEATHER CONDITIONS and seek shelter immediately.
The extreme fire behavior we have been seeing on a regular basis is placing firefighters and the public at increasing risk. Wildland firefighting has always been dangerous, but the “new normal” is a level up on that scale. Firefighters and the public need to recalibrate their thinking about how vegetation fires move across the landscape.
Pyrocumulus clouds, before the last five to 10 years, were not nearly as common as they are today, and are one of the most obvious visual examples of how climate change is affecting wildland fires.
(To see all articles on Wildfire Today about the Bootleg Fire, including the most recent, click HERE.)
The information below about the Bootleg fire is from the Incident Management Team, July 14:
“Power distribution is interrupted in SE Oregon from Fields, OR to Winnemucca, NV with power to pumps supplying agricultural ranches out. There are significant impacts to the CA power grid, causing strain on their power distribution system, which is a very sensitive issue. Smoke has already caused arcing due to the conductivity of the carbon particles in smoke, which impacts power distribution lines well ahead of the fire. Klamath and Lake County Sheriff and Emergency Managers are handling evacuation planning.
“Fire remains very active with significant acreage increases due to hot, dry, breezy conditions, and plume dominated fire behavior. Poor humidity recovery at night is contributing to active fire spread through the night time period. Robust spread rates are being generated by drought effected fuels. Expecting similar conditions for the next several days.
“Although it is predicted to have slightly cooler temperatures in the next couple days, temperatures remain above normal and RH values are expected to be in the lower teens. These conditions paired with gusts winds at times will test control lines, and are expected to contribute to active/extreme fire behavior. Unstable conditions will exist over the area, but smoke thickness will dictate fire weather conditions.”
The weather forecast for Thursday morning in the Beatty, Oregon area calls for 88 degrees, 15 percent relative humidity, and 6 mph winds out of the southwest. After 5 p.m. the wind will be out of the west and northwest at 11 to 14 mph gusting to 21 mph. Another day of active fire behavior.