BOULDER, Colo. — Though it is still unknown what exactly sparked the Marshall Fire in Boulder County, one thing that is clear is that a confluence of different climate factors fueled its destructive spread.
The Marshall Fire, which eventually consumed about 6,000 acres, started on Thursday, December 30, It was a day when Boulder County was in the midst of an “extreme drought,” according to the U.S. Drought Monitor. The county hadn’t received rainfall since mid-summer and the time from June and December was the warmest period on record for the area.
There were also extreme winds December 30, reaching more than 110 miles per hour in some parts of the Denver metro area. So when the fire started, there was little anybody could do to prevent its rapid advancement through Superior and Louisville.
“Just a tremendous wind day,” said Greg Hanson, a warning coordination meteorologist at the National Weather Service’s (NWS) Boulder office. “And then you add the ongoing drought conditions we've been in—just two bad combinations. And so when that spark lit, the fire was off to the races.”