Monday, May 16, 2011

The Burn-out in Cave Creek Canyon

At this morning's briefing, the fire crews were told that the burn-out operation in the South Fork of Cave Creek Canyon is proceeding so far at a low intensity. That is very good news.

After the briefing, with smoke from Horseshoe Two Fire
(Photos by Narca)

Right now our weather is transitioning from a high pressure system (with mild wind) to a major deep pressure system, now building in the Pacific Northwest. As that low pressure system moves across to the north of us, it will bring high winds again. So the crews are doing everything they can in the next two days to accomplish a low-intensity burn-out in critical habitats, before the wind can once again control what happens on the Horseshoe Two fire. The relatively light winds today are predicted for about 10 mph, with gusts to 25 or 30 mph. Winds continue to blow mainly from the southwest.

On the day of origin, Horseshoe Two ran north for about 7 miles during a single day, while in the grip of high winds. Right now the fire is about 2 miles from reaching the American Museum of Natural History's Southwest Research Station. The distance seems small to me (after seeing just what this fire did on the first day!), but the difference now is that the fire teams are in place and actively controlling the intensity and speed of the fire.

Fire map for May 16

Yesterday a team working in the Herb Martyr area found a more direct checkline that they can use to moderate the fire. Repellant has been laid, and preparations continue today to back the fire into the basin. A backing fire burns moderately, with mostly low flame height, and achieves a beneficial burn. A fire rushing uphill is much more extreme and can torch entire stands of trees. So the crews are backing fire into South Fork and into the main Cave Creek Canyon. So far, so good. If work goes as planned, the backburn from the research station area may be lit off tonight.

Today's major operations. Red dots are hotspots. Purple dots were hotspots, now cold.

Conditions remain very dry, and last night there was only a poor recovery of relative humidity, to about 15-16% overnight. It will be back in the single digits today. The fire behavior specialist exclaimed today that this fire continues to surprise him by the way it is following grass fuels, no matter what the wind does. This is anomalous behavior, due to the extreme dryness of fuels. Today's probability of ignition will range from around 80% when cloud cover is present, to 100% when the clouds burn off. (That is the measure of how likely a fire brand is to ignite more fire, should it land on fuel.) This anomalous behavior increases the risk to firefighters.

To the north, east, and south, the fire perimeter is holding very well and getting cold. The burn-out to Horseshoe Canyon road has been completed and the fire team is happy with how it went. Patrols check these areas regularly.

The black borders on this map are considered secure.

Most of the fire activity continues to be in the western region. Aerial ignition will continue along ridges in the vicinity of the fire's spread, to slow it by creating fires that back down the ridges to meet the main fire. Terrain in the high country is very difficult to work from the ground, so air operations are focused there. Snowshed Peak has burned, and the fire has not yet reached Chiricahua Peak.

Teams will be visiting Paradise today and evaluating the readiness of homes there, in case the fire gets away from us during the next high winds.

The statistics are these: 26,502 acres burned; 20% containment so far; 630 people working with the fire crews; and a total of $4.4 million spent so far.

A newspaper article which ran yesterday in a Tucson paper's online edition stated unequivocally that illegal immigrants started the Horseshoe Two fire. Apparently Border Patrol agents had tracked four illegal aliens to the point of origin of the fire. Much of the article was biased, but the assertion is correct that the fire was checked from burning into Portal on the first day by the large, heavily-grazed pasture of the Three Triangle Ranch, although the bulldozer line put in by the fire crew also was important. I walked part of the bulldozer line, and it is obvious that part of the fire stopped there.

My reporting on this blog is going to change after today. Alan and I are leaving for a trip to Eastern habitats. Raymond VanBuskirk will stay in our home while we are gone, and he, Peg Abbott, and Reed Peters will continue to attend the early morning briefings whenever possible, and send new information that I can post when internet connections allow. You will be treated to new perspectives on events here. I, however, won't have the same personal grasp on developments that comes from attending the meetings and observing firsthand how well a really skilled, professional fire team handles a crisis like this one. Together with my friends, we'll do our best to keep everyone informed.

Leaving right now is very difficult, yet I do need to get out of the smoke, and we have been planning to see faraway friends and family for some time. We are, at least, leaving the outcome in good hands.


  1. Enjoy your trip and thank you for the informative maps and information.

  2. Thanks Narca, I get the best info from your blog.
    I hope you and Alan have a wonderful trip.