Horse Fire V

Acrid smoke in the air this morning — smells very strongly, with an acidic bite. It’s reminiscent of the Cedar Fire three years ago; not a pleasant memory.

The map at right was current as of 6 AM this morning. I’ve had some questions about the satellite data and exactly what it’s showing. Here’s what I understand after some research last night and this morning.

The MODIS data shows up as one kilometer (about 0.6 miles) diameter circles with slanted line shading in them. Where there’s a circle, the satellite detected heat. The heat measurement is integrated over the entire one kilometer circular area — so a pinpoint of extremely intense heat could trigger it, and so could a broad area of much lesser heat. It does not necessarily mean fire — but it probably indicates at least some fire somewhere in that circle. The colors of the splotches indicate their age. Red splotches are less than 12 hours old; orange splotches are 12 to 24 hours old, and black splotches are more than 24 hours old.

The WF-HMS data is much different. This is data generated by the NOAA as a result of a human analyst who is looking at several different sources of data. The data available to the analyst includes MODIS, visible light imagery, smoke plume detection, and more. The analyst then makes an estimation of where actual fires are, placing dots on a 250 meter grid to indicate them. They’re visible on this map as relatively small solid red dots. The red dots are less than 24 hours old; if there were any data 24 to 48 hours old, they’d show up as yellow dots.

I’ve hand-drawn a few features on the map:

The green splotch at left is the area where our home is.

The purple arrow points to a purple dot; that’s where we stood on Sunday evening when we reconnoitered the fire. Just above and to the right of that purple dot, you can see one of the small red WF-HMS dots (just to the right of the black line that indicates Lyons Valley Road).

The blue horseshoe shaped line (open to the left) is the approximate ridge line of the line of mountains that forms Lawson Valley (where we live). The fire is on the other side of that ridge from us. This matters because ridgelines form naturally defensible lines for the firefighters — fire moves much more easily up a slope than it does down a slope, and the ridge makes and easy target for the aerial tankers. Having a very defensible line between us and the fire is a very good thing that we are taking some comfort from.

The large yellow shaded area at top and toward the left (west) is the community of Carveacre. There has been a voluntary evacuation of Carveacre for most of the past 48 hours, and we’re still trying to figure out why. The fact that the CDF has the evacuation in place is worrisome, as the community of Carveacre is (as you can see) quite close to us.

I just listened to the latest CDF report, and its a real eye-opener. First thing: they’re now reporting 15,500 acres consumed, which is very close to the estimate I made yesterday from the satellite data. There’s a lesson there: the CDF reports are not current. CDF is now reporting a lot more assets on the fire: 770 firefighters, 102 fire trucks, 8 bulldozers, 7 helicopters, and 6 aerial tanker planes. They’re still reporting just 5% containment, which probably mainly reflects the fact that the fire is mostly burning in remote wilderness areas.

The CDF also reports that with the evening, the actively burning areas are much diminished — but with the heat of the day, they expect strong flareups in three areas: Secret Canyon (the part burning to the northeast toward Pine Valley and Guatay), Hauser Canyon (the part burning to the east, and nearing the western edge of Lake Morena), and (most worrisome to us) the part burning on all sides of the northern half of Lake Barett. The latter part is four to five miles away from our home; it’s the area I took pictures of on Sunday.

As I prepared this post (and after I prepared the map at right), there was another satellite update. The MODIS data is largely unchanged.