There have been varying accounts as to whether Dec. 30 carried a Red Flag Warning.
Boulder County Sheriff Joe Pelle has said publicly that there was a Red Flag Warning on the day the Marshall fire broke out. But the National Weather Service in Boulder told The Denver Gazette that it issued a "high wind warning" — which carries with it a ban on fires — at 3 a.m. Dec. 30.
Although the winds were high and the fuels were cured and dry, the weather service office did not call for a Red Flag Warning because humidity levels were not below the 15% threshold required for the Red Flag classification.
"Humidities that day were at 20-25%," said Jennifer Stark, the office's meteorologist in charge. "It was absolutely not OK to burn any fires that day. Anyone who lives in Colorado knows how dry it has been in the fall and winter."
According to Boulder County's website, "During any of the following weather events, open burning is not allowed in unincorporated Boulder County from time of issuance until midnight in which the event expires: Red Flag Warning, High Wind Warning, High Wind Watch, Fire Danger Warning, and Fire Weather Watch."
It then advises residents that it is critical for visitors and residents to do anything they can to prevent fires.
Pelle has said in news conferences that the neighborhood at Marshall Road and Colorado Highway 93 is at the center of the investigation. The Boulder County Sheriff's Office has denied numerous requests for records showing the number of times deputies were called to that area, citing its ongoing investigation.
The National Weather Service reported that winds were gusting from 81 mph in South Boulder and up to 99 mph at highways 93 and 72. By noon, that spot had a peak gust of 115 mph. Those strong winds shifted east toward all of Superior and most of Louisville between 12:30 and 2 p.m.
The winds started to calm down “through the afternoon and late evening hours, but unfortunately, much of the destruction had been done,” according to the National Weather Service in Boulder.