COLORADO SPRINGS — Although we all saw the first wisps of smoke from the Waldo Canyon fire on Saturday, June 23, 2012, the story of the fire really begins earlier in the year, during the late winter and early spring.

As you can see in this series of images from the U.S. drought monitor, the first six months of 2012 were very dry across Colorado and drought expanded rapidly across the state.

The image comparison below shows the dry weather continuing in June. Notice the deepening of the drought with growth of Severe Drought (Category 2) and Extreme Drought (Category 3) over a large area from June 5th to June 26, the day the fire blew into Colorado Springs.

The stretch of dry weather in June came with record heat. In fact, five days in a row of record high temperatures concluded on June 26, when the fire came into town. On that afternoon, the hottest temperature ever recorded in Colorado Springs, 101 degrees, was measured at the airport.

A wave coming up from the southwest brought moisture in the mid levels of the atmosphere, and instability over the mountains helped to develop some thunderstorms along the continental divide.

Wind from these thunderstorms advanced east toward the Pikes Peak region and helped to develop some new thunderstorms between 3:30 and 5:00 p.m.

These thunderstorms intensified on the northwest flanks of Pike’s Peak and quickly collapsed.

This strong downdraft of air that resulted moved very quickly from west to east across the fire and, with wind gusts of 65 miles per hour reported that day, they drew the fire into the Mountain Shadows neighborhood.

Here’s a look at 3D radar showing what radar returns in the vertical looked like. For orientation, the purple on the right half of the screen is the pyrocumulus/smoke plume from Waldo and the left side of the screen are the thunderstorms that formed, strengthened, and died over northern Teller County.

It is recommended to watch the video through a couple times. You’ll notice the storms collapse on the lefthand side of the screen and then Waldo’s pyrocumulus cloud being pushed at the surface across the north side of the city as the outflow from the storms moves through the fire. Notice how quick that change happened in the foothills as homes began to burn. Here’s what it looks like on a timelapse from the northwest of town.

The wind shift occurred quickly, changing lives forever. If the thunderstorms had never formed to the northwest of the fire that day, the history of the Waldo Canyon fire on June 26, 2012 would be very different.