On August 18, 1937, a lightning strike started the Blackwater Fire in Shoshone National Forest, approximately 35 miles (56 km) west of Cody, Wyoming, United States.

Fifteen firefighters were killed by the forest fire when a dry weather front caused the winds to suddenly increase and change direction.

The Blackwater Fire consumed 1,700 acres (690 ha) of old-growth forest dominated by Douglas fir trees on the west slopes of Clayton Mountain.

Though most of the firefighters consisted of Civilian Conservation Corps (CCC) employees, they were led by more experienced United States Forest Service (USFS) fire managers.

The creek is 12 mi (19 km) long and descends a steep gradient before it empties into the North Fork Shoshone River, across from U.S.

Routes 14/16/20 immediately west of Mummy Cave and 15 mi (24 km) east of the border of Yellowstone National Park.

[2] The firestorm deaths occurred on the west slopes of Clayton Mountain, approximately 5 mi (8.0 km) south by trail into the canyon.

[3][4] The canyon consists of numerous ravines and small ridges, which form a washboard landscape shaped by extensive erosion of the volcanic igneous rock that constitutes the Absaroka Range.

[6] In 1937, firefighters did not have portable radios for rapid on-scene communication or helicopters to bring supplies and provide water drops.

[12][15] The steepness and ruggedness of the terrain in Blackwater Canyon meant firefighters had to access the fire on foot, carrying all their supplies.

On the Blackwater Fire, pack horses were used to ferry supplies from the access roads to an upper base camp.

[15][20] By the evening, it had expanded to 200 acres (80 ha), and 65 firefighters from the United States Forest Service (USFS), which included CCC company 1852 from the Wapiti Ranger District of Shoshone National Forest and employees of the Bureau of Public Roads (BPR), were constructing fire lines along two flanks of the fire.

[24] Due to a long overnight journey, the CCC members from the Tensleep District of Bighorn National Forest did not commence response to the fire until after noon on August 21.

The construction was led by USFS Rangers Alfred Clayton and Urban Post, and their crews consisted mainly of the Tensleep CCC camp and some from other entities.

[15] The USFS did have spotters in an aircraft providing aerial observation of the fire behavior that was radioed to the Wapiti ranger station.

Winds blowing generally from the southwest increased to 30 miles per hour (48 km/h) as the dry front approached at 3:30 pm.

At 4 pm, the spot fires started to crown and Clayton sent a handwritten note to Post requesting additional manpower.

[24] By the time the note reached Post, the firestorm commenced, racing east up the ravines and gullies and trapping Clayton and his crew near the dam they had built.

[27] Post led more than 40 firefighters, consisting of USFS, CCC, and BPR employees, up the ridge seeking an opening in the forest to take refuge.

[29] Crammed together on the outcropping, Post's men moved around to avoid the flames and USFS employee Paul Tyrrell (who later died) used his own body to keep several CCC firefighters from panicking and to shield them from the fire.

[20] The Blackwater Fire is tied for fourth involving the greatest loss of life by firefighters on a wildfire in U.S. history.