(CBS4) – Dry and hot conditions in September and early October in Colorado set the stage for the massive blowup of the East Troublesome Fire on Oct. 21, 2020. The fire started on Oct. 14 northeast of Kremmling in the Arapaho National Forest. A year later, investigators have not determined what sparked the third largest wildfire in Colorado state history.

The East Troublesome Fire along Cottonwood Pass on Oct. 21, 2020. (credit: Andrew Lussie/Inciweb)

Weather data from Kremmling Airport, the closest official weather station to the fire, starkly paints that worrisome weather picture in Grand County a year ago. Meteorologist Chris Spears analyzed the numbers which he says show September was extremely warm and dry in that area. Kremmling Airport only reported 0.11 inches of precipitation. The normal precipitation for that month in that area is 1.28 inches. Temperatures most days were in the 70s and 80s. Spears said that trend continued into October with only 0.01 inches of precipitation reported until a strong storm passed through on the Oct. 26.

But in the days before that storm moved in, the East Troublesome Fire dangerously exploded. It had grown every day that week until it was 18,550 acres (at 5:15 p.m. on the Oct. 20). In 24 hours, it more than doubled in size to 38,496 acres (at 6:20 p.m. on October 21).

But that evening — Oct. 21 — proved cataclysmic. Within hours, the fire exploded, more than tripling in size in just four hours, reaching an acreage of 125,588 by 12:30 a.m. And that rapid growth continued into the day of Oct. 22 where it consumed another 44,000 acres before that growth finally slowed after it reached an acreage of 187,964 at 1:33 p.m. on Oct. 23.

East Troublesome Progression Map (credit: Inciweb)

To see a closer image of the map above, click here.

When that storm finally started moving on Oct. 24, the wildfire was listed at 189,543 acres, and when the snow finally arrived and the temperatures dropped, the East Troublesome Fire had reached its final acreage of 193,656.

Firefighters declared it was contained on Nov. 30, only after it killed two people, Lyle and Marilyn Hileman, destroying their home in Grand Lake. A total of 366 homes and 214 other structures were damaged or destroyed.

Raetta Holdman