As of press time on June 24, the Pocket Fire continues to burn about seven miles north of Sedona and west of Oak Creek Canyon on the Coconino National Forest, about a mile and a half due west of the Junipine area.

Readers and fire-watchers will have noted by now that the fire had grown, again as of press time from about 250 acres to 691 acres.¹ Initial assessments were about 500 acres by the end of the first day of the fire, Friday, June 19. These assessments are made from the ground and the air with visual estimates of the land area that a wildfire is burning. It takes time to get an infrared reading of the actual burn area, which generally reduces the size of a wildfire in the first few days, and provides a more accurate analysis of the actual area on fire or which has burned.

Fires burn dynamically in unpredictable terrain, producing dense smoke that can hide perimeters and they spread unevenly. They may create “unburned islands” inside the outer boundaries from a number of factors from winds or fire fuels or water sources or terrain features like rock outcroppings, all of which can create natural fire breaks inside the perimeter.

Spot fires are created when embers from burning material jump a fire, some of which may burn temporarily before sputtering out or being extinguished by crews on the ground or from the air or burn and grow the fire when the rest of the blaze reaches it. For instance, on Tuesday, June 23, officials reported that several spot fires were detected across Forest Road 231 to the north of the main fire perimeter, the largest of them reaching a half-acre, but the night shift fire crews were able to suppress those immediately.

Because a fire perimeter is a dynamic, living chemical reaction, not a static thing, a measurement is a snapshot of a moment.

That said, fire crews on the line create fire breaks with controlled back burns, limiting a perimeter from the outside in so that when the conflagration reaches the back burn area, there’s little or nothing left to burn and the wildfire ceases growing along that vector.

In Oak Creek Canyon, Hotshots reportedly built handline and reopened lines established during the 2014 Slide Fire. Other crews built containment lines to the south of the fire to protect areas along the vector toward Sedona proper.

Fire managers are preparing for extreme fire behavior expected through this weekend, so unless there is a surprise downpour over the area.

As I write this, there has been a sprinkling of rain in Uptown. The National Weather Service is predicting a 20% chance of showers and thunderstorms before 11 p.m. Wednesday; a 30% chance of showers and thunderstorms after 11 a.m. Thursday, June 25, a 10% chance of showers and thunderstorms before 11 p.m. and then mostly sunny and clear from Friday morning, June 26, through Tuesday, June 30. Any thunderstorm can bring localized wind gusts, which could exacerbate the Pocket Fire, and dry lightning strikes, which could spark wildfires elsewhere.

The cause of the Pocket Fire is still underdetermined. While social media users are immediately pointing fingers at a human cause, we did have a brief thunderstorm the weekend prior. While most wildfires are the direct result of a lightning strike or human cause that immediately sets off a blaze, a “holdover” fire can ignite and smolder for days, sometimes weeks, burning both above ground in isolated areas or underground in root systems undetected before reaching fire fuels that turn a slow-burning blaze into a full-blown wildfire. According to fire officials, these “holdover” fires are more common than people realize and many burn themselves out without ever becoming bigger than isolated copse of trees.

While we can’t say this is the cause either, it will be up to fire investigators after the Pocket Fire has passed to determine what may have caused it.

There are two positives. The first is that fire officials have lifted the evacuation order for Oak Creek Canyon, allowing residents and property owners to return, though visitors are still prohibited from entering. The second is that the Pocket Fire is burning an isolated area far from any inhabited area or structures, so no homes or lives are at risk.

Stay safe, hope for the best and know that the fire crews on the line and pilots in the air are working hard to contain and extinguish the fire. We will continue to update readers, residents and visitors on redrocknews.com and our social media pages, at @sedonanews.