The spread of the Arnica fire, now mapped at 9,300 acres, has slowed over the last two days. The map below which depicts heat detected by satellites, shows a major reduction in heat compared to what the fire was doing two to three days ago.

An updated map of the Arinica fire in Yellowstone northeast of West Thumb, showing heat detected by satellites at 3:30 a.m. MT Sept. 29. The red areas contain heat that was detected within the previous 12 hours. The map also shows the Butte fire southwest of Cooke City which had quite a bit of heat Monday night. Park spokesperson Stacy Vallie told us that as far as they know it is not spreading very much and was last mapped at 180 acres. GEOMAC

But it certainly is not out yet. The Mt. Washburn web cam occasionally is socked in by smoke as the wind sometimes blows the smoke directly at the lookout.

Fire personnel have been running an irrigation system to protect structures. Night time temperatures have obviously been below freezing.

NPS photo

NPS photo

The weather today could be conducive to additional fire spread, with the forecast calling for 18 mph SE winds gusting to 28, a high of about 60, and a minimum humidity of 21%.

But rain is expected to begin by 6 p.m. this evening and should change to snow by midnight. A total of about 6 inches of snow is predicted through Thursday morning, which most likely will be the fire season ending event for Yellowstone. The forecast calls for chances of more snow all the the way through Monday, October 5.

(UPDATE at 7:38 p.m., Sept. 29.  The Weather Service has changed the forecast. The rain has been scrubbed, and the snow is expected to begin Tuesday night at midnight. It should continue through Wednesday night, with about 6 inches accumulating. There will be a chance of additional snow every day through at least Monday.)

The biggest problem facing firefighters now is how to avoid having to deal with frozen and broken irrigation pipes and pumps as the temperature dips into the teens Wednesday and Thursday nights. Removing a massive irrigation system in the snow is something I imagine they are not looking forward to.

HERE is a link to a more detailed version of the map above.

Wildfire Today has obtained these photos of the Arnica fire northwest of Yellowstone Lake in Yellowstone National Park. All are National Park Service photos.

2:52 p.m., September 25

2:33 p.m. MT, Sept. 26

Structure protection, 2:55 p.m., Sept. 26

To help protect structures the park is using a metal pipe irrigation system and a high-volume pump first used on the 1988 fires. If you look closely at the photo above and squint your eyes a little, you can see a hint of the irrigation pipe leading from a pump on the lake shore.

Here is a photo from InciWeb showing some of the irrigation system in action.

NPS photo from InciWeb

Thanks Tonja and Joe

When structures are threatened by wildland fires, sprinklers are sometimes placed on roofs, but installing them means climbing on the roof. A company in Florida has developed a sprinkler that can be placed on the peak of the roof while you stand on a ladder at the side of the structure. The trick is attaching 5-foot sections of PVC pipe to the sprinkler which are then used to push the roller-mounted unit up the roof. Then a garden hose is attached to the PVC pipe. It looks like this could be a worthwhile addition to structure protection kits.

The cost for one complete unit is around $300, depending on what state it will be shipped to.

Be warned, that when you go to the site, a damn video starts playing automatically. I hate that. You can stop the video by clicking on “close video”.

If you live in St. Louis or Lake counties in Minnesota, you could be eligible to submit an application for grant assistance to install or upgrade a wildfire sprinkler system. According to the Timberjay newspaper:

“Both counties will be seeking federal funding through FEMA to help pay the cost of installing sprinkler systems for homeowners, especially for those in areas identified as at high risk for wildfire.”

Should the federal government be buying sprinklers to be installed on private land?