Left Fork Fire in Utah takes off again after being dormant for a month

An escaped prescribed fire is being investigated as the original cause

Updated at 6:51 a.m. MDT June 20, 2022

3-D map of the Left Fork Fire
Map of the Left Fork Fire looking north-northeast. The green line was the perimeter May 11, 2022. The red line was the perimeter at 9 p.m. MDT June 19, 2022; the orange areas indicate intense heat at that time.

The Left Fork fire continued to spread to the northeast Sunday night in the Dixie National Forest in Southern Utah. When it was mapped at 9 p.m. Sunday it had burned approximately 2,600 acres. At that time it was about 2 miles west of the 87 road and Bryce Canyon National Park.

Map of the Left Fork Fire
Map of the Left Fork Fire. The green line was the perimeter May 11, 2022. The red line was the perimeter at 9 p.m. MDT June 19, 2022; the orange areas indicate intense heat at that time.

 


9:50 p.m. MDT June 19, 2022

Left Fork Fire map
Left Fork Fire map, showing heat (at the arrow) detected by a satellite at 1:57 p.m. June 19, 2022.

The Left Fork Fire in Southwest Utah has taken off again after being dormant for about a month on the Dixie National Forest. It was first detected May 9. On May 10 the Forest Service said it ignited from material still burning from a prescribed fire conducted April 7, 2022.  On May 11, 12, and 13 the daily updates about the wildfire posted by the Forest Service stated it was “human caused.” The escaped fire burned 97 acres in early May.

Apparently undetected smouldering material on or under the ground, such as stumps, duff, or tree roots, must have continued burning for weeks after the prescribed fire, and later after the spread of the 97-acre wildfire was stopped. Follow up monitoring of both events either did not occur or was inadequate to detect the still burning fires. The strong winds on June 18 may have fanned it back into an active burning condition, and it spread across a fireline, or hot embers were blown outside the perimeter into receptive fuels.

Left Fork Fire, June 19, 2022
Left Fork Fire, June 19, 2022, by @april_reeve.

On June 18 the fire began spreading again pushed by strong winds. Utah Fire Information said that day it was estimated at 300 to 500 acres. Sunday afternoon, June 19, it had grown to 600 to 700 acres in rugged terrain, putting up a huge smoke plume affecting the air quality in eastern Utah and southwest Colorado.

Satellite photo of smoke from the Left Fork Fire,
Satellite photo of smoke from the Left Fork Fire, 7:16 p.m. MDT june 19, 2022. NOAA.

The original cause of the fire is still listed as “human caused.” There are dozens of ignition sources that cause wildland fires. Saying it is caused by humans only eliminates two — volcano and lightning — and both could be ruled out very quickly.

Left Fork Fire escaped prescribed fire
Firefighters construct fireline on the Left Fork Fire in Utah which was apparently caused by an escaped prescribed fire. Posted by the Dixie NF, May 12, 2022. Photo by Mervin Garcia, Engine 322.

Sunday afternoon the Left Fork Fire was spreading to the northeast and was about 2 miles west of Bryce Canyon National Park, 7 miles east of Highway 89, and 20 miles south of Panguitch; it had reached Blubber Creek drainage. It is burning between 8,000 and 9,000 feet above sea level.

The area was under a Red Flag Warning Sunday for relative humidity in the teens and 20 mph southwest winds gusting at 35 to 40 mph. The strong winds kept helicopters and fixed wing aircraft grounded, unable to assist firefighters on the ground.

The NWS spot weather for Monday calls for 70-72 degrees, 10-12 percent relative humidity, and 5 to 15 mph winds out of the west shifting to southwest. Tuesday will be about the same except the wind will be out of the southeast at 10-20 mph in the afternoon.

A Color Country Type 3 Incident Management Team will assume command of the incident Sunday evening.

The map below shows the location of the Left Fork Fire after the spread was temporarily stopped around May 11, 2022.

Left Fork Fire 3-D map, May 11, 2022
Left Fork Fire 3-D map, looking north May 11, 2022.

About a week after the first attempted suppression of the Left Fork Fire the US Forest Service announced May 20 in a press release that a “pause” was in effect for all prescribed fire operations on National Forest System lands. The reason given was “because of the current extreme wildfire risk conditions in the field…while we conduct a 90-day review of protocols, decision support tools, and practices ahead of planned operations this fall,” Forest Service Chief Randy Moore said in the statement. At the time several other prescribed fires had recently escaped in addition to the Left Fork incident.