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FIRE RAWS UNIT ON THE BIRCHER BURNED OVER
On Monday, July 24, on the Bircher Fire near Durango, Colorado, a NIFC FIRE RAWS unit was burned over by a fire that blew up and made a canyon-gobbling run in the middle of the night. The FIRE RAWS is an enhanced RAWS unit that collects weather information and can alert firefighters on the line by transmitting that information via radio. The first blaze to burn over a FIRE RAWS unit, the Bircher Fire was for a couple days a fire of the nightmare class.
Hartman's team, who were managing the incident, also ordered the FIRE RAWS from NIFC. "We were dispatched on Saturday from Boise," says Denise Buske, one of the two specialists who came with the unit. "We arrived Sunday about noon and deployed the unit about 3 p.m. at the Park Point Lookout."
The FIRE RAWS, in its second year of testing, detects any unusual measurements – such as high winds or a change in temperature or humidity – and then can automatically warn firefighters over the radio. The system includes a complete weather station; it broadcasts weather observations over the GOES satellite to locations including information on the internet, and can be called over the radio by firefighters. Parameters critical to fireline safety can be programmed to alert firefighters about wind shifts, humidity change, or a sudden temperature rise or decline. Sensors on FIRE RAWS, which are calibrated before each use, monitor wind speed and direction, peak winds, air temperature, fuel temperature and moisture, relative humidity, solar radiation, and programmed warning thresholds including low RH or high winds.
Park Point Lookout, where the unit was deployed, is the highest point in the park. "There's an escarpment that runs on either side of the point," says Buske, "on the east and west sides of the lookout. It's a wide area, and we wanted the winds on the east side, so we deployed it there about 50 feet from the lookout. There was about two feet of dirt and gravel all around, with small brush on the south side. We figured there was somewhat of a buffer zone around in case it did get burned over."
"There was low to moderate coverage of fuels where we set it up," says Mario Marquez, one of the technical specialists with the FIRE RAWS unit. "It was mostly piñon-juniper and gambel oak fuels before the fire burned over the point. There's no fuels at all there now."
"We figured we had several options if the fire did burn over the point," says Marquez. "We could pull the FIRE RAWS now and save it, but if we did, there wouldn't be any weather data from the unit till the next morning."
"Like they said at the briefing," adds Marquez, "you should expect the unexpected. You can try to predict and foresee, and you can use your training and experience. But if I could predict stuff I wouldn't be doing this."
The next morning at the briefing they were told that the FIRE RAWS had been burned over at 1:30 in the morning. WEATHER AND FIRE BEHAVIOR: FROM EXTREME TO BIZARRE
During the briefing on Saturday night, the weather forecast and fire behavior forecast for Sunday were outlined for fire personnel. "We looked at the numbers and explained them," says Maxwell, "and we discussed what would happen with fire behavior if the fire was driving the weather. You can't predict a plume-dominated event, but we explained what could happen if we got into that situation. Then we went back outside, and that's when everything basically went nuclear."
"The plume had set up over this north-south canyon and then burned into the middle," explains Maxwell. "We had up-canyon winds, and that got the wind going up the canyon, with a hot fire, and pulled it right up into the column and just blasted. It consumed all fuels in all directions, and after that, the plume took off. The fire had started to calm down some, to the point where it was just extreme, and the crews did some burnouts. But then a dry thunderstorm formed and moved south, and we had a push of wind from the east. That blew the column over, making it a wind-driven fire. That continued for about an hour, enough that the fire blazed over the next two canyons. Then the winds went away and it became calm."
"About 9:30 or so the Type II team came through from the Hovenweep Fire," says Maxwell, "and we figured as the sun went down it would cool down the top of it and the column would collapse. The thing just pushed back out like a plunger. As it started to collapse, you could see the top come down, and the smoke just poured out in all directions. It cranked outflow wind from it like a thunderstorm, and we all had ash and smoke blown in our faces. It was getting dark by now, and people out on the road said it was unreal, with an orange glow dominating the top of the mesa."
Maxwell says they picked up the wind gusts on the FIRE RAWS before the fire got there. "It was set up about three miles west of where the fire had been in the afternoon. We had it set for RH – if it was below 15 percent at 8500 feet, we needed to know about it. When the fire burned over, the RH dropped to zero."
"The lookout radioed in that it was being burned," says Maxwell, "and then he bailed. The repeater was burned and stopped working, and that was charred up pretty badly. They went up there about 3 a.m., because they had to get that repeater working. It was chaos in the middle of the night."
Marquez says they could tell the next morning, when they tried to get the data outputs from the RAWS unit, that it had been burned over. "Monday morning we saw it wasn't putting out data, and we knew the fire had got to it – it just got there sooner than anyone expected. The data told me a lot without even coming out here. I could determine the fire pattern when the fire hit it. This was a wind-driven topography fire, and when it crested over the saddle it made an upslope run."
"When we got up here," says Buske, "there wasn't a piece of vegetation anywhere it around it, but the unit looked almost normal. The box wasn't charred, but the fuel moisture stick was browned. The cables were melted and bubbly, but all the sensors were working. The power had dropped, but other than that we found the unit was able to sustain some pretty good heat. Now we know that it does really well – it continued to put data out the whole time."
The team had a spare unit in the NIFC trailer, and they set that up on the ridge, too. "We took down number 3 and set up number 4, and number 6 is several miles down the road. There are weather stations owned by the Park Service on the ends, but they're all on the west side of the park. We can't put one on the east side because there's no way to get to it."
Barbo says the sensor that showed the most damage was the fuel stick. "It was dark brown, and the cables were connected, but the rubber bushings were rendered unusable. We're more concerned with the cable setup because without them the sensors don't work. It looks like we sustained only minimal damage to the sensors. All sensors have been recalibrated, the cables have been replaced. The unit is in new condition and ready for its next assignment."
One of the units was moved on July 27 to another division to support operations on the fire, according to Barbo. He says the units on the Bircher Fire are even assisting with aviation resources. "It's a safety issue," he says. "Air ops are using the data to help with retardant spread and mixtures, elevation, wind direction and approaches."
According to Kolleen Shelley, U.S. Forest Service national RAWS coordinator, the USFS and the BLM are working together on field implementation for the program. "Though the technology was available for some time," she says, "people at the remote sensing weather unit at NIFC started getting requests from field personnel for weather data that was representative of what was happening on the fireline. They combined the hardware they had with enhanced software and made the firefighters' need a reality."
Shelley says the FIRE RAWS units not only collect a wide array of fire weather data, they can also record all the data for the duration of an incident. This data automatically goes out every hour via GOES satellite to ASCADS (the automated sorting conversion and distribution system), which forwards the data to the Weather Information Management System (WIMS), the BLM's web server, the National Weather Service, and the Western Regional Climate Center.
"We are working with the incident management teams on how multiple units are deployed," says Barbo. "The FBA and the IMET want the full round of all the data that comes up, but the ops people are saying they don't need all that. They need the basic operational period fire weather. They want to be able to key their radio and interrogate the unit and get immediate and accurate weather data. They want just the basic four things – relative humidity, wind speed and direction, and air temperature – in that order. The FBA and the IMET, though, get the full complement of data from the station. That information is just for them in fire behavior – so the first unit we put out on a fire is centrally located for an overall look at the conditions for the FBA and the IMET. When we put a second or third unit on a fire, though, we can put it out for the ops people. We get together with the safety officer, the IC and the division group, and communications, and we find out who they want to designate for receiving warnings issued over the radio by the unit. The team may want it to go directly to safety, or the division group. We don't want this to be a warning issued to all the firefighters with radios, because it's not keyed up for Division A or Division C – you don't want a hazard warning given to everyone if it's just one division that's affected. What the unit's designed to do is issue a warning to an individual on the command staff who gets together with communications and then issue the warning, say to Division A – your RH is 7 and your wind speed is 30 and this is what we want you to do."
The burned-over unit has now been refurbished and recalibrated, according to Barbo, who explains that each unit is sent out with one fully qualified electronics technician and one red-carded fire person with RAWS experience. "Both our techs and our fire guys are fully carded," he says, "but we've run out; we could use probably five more with the team. We just don't have the resources now. We're strapped. We have two more units available right now, but we don't have a team to take them out."
Barbo says the unit and its use are being incorporated into ICS as a tool to advise someone in the command staff to issue a warning when necessary. But he adds that not everything is always by the numbers. "If you get into a situation where there is a dangerous canyon, and they're going to put crews in there, we can deploy a unit right where they are. The crew boss has the code and can access the unit at any time. The others will hear the supe hitting the unit, and they can follow the RH's while they're there. But they have their thresholds – If the RH hits 7 then my crew is going to be out of that hole, that's my threshold."
"We have people come up to us in the chow line," says Barbo. "‘Are you guys the FIRE RAWS guys? Yeah. Well, thanks for covering us out there, and for teaching us how to use this.' That's what it's all about, what we care about – safety for those crews out on the line."
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Chuck Maxwell, fire weather program leader for the Albuquerque office of the National Weather Service, was the incident meteorologist (IMET) ordered by Joe Hartman's Type II team and dispatched to the fire. "I came up Saturday morning," he says, "and I just followed the smoke trail and the plume from New Mexico. Just past the continental divide I could see smoke hanging in the valleys. When I got up to the Colorado state line I could see the plume – at 9 o'clock in the morning. I checked in before noon and spent about three hours getting my stuff set up. The next day was just a nightmare."
The FIRE RAWS units are individually calibrated and fine-tuned for accuracy. "Each of these is specially calibrated so we know they are right on," explains Mark Barbo, logistical FIRE RAWS coordinator at NIFC. "The units have special sensors that are accurate below 10 percent relative humidity. The FIRE RAWS units are calibrated for accuracy beyond the manufacturers' specifications, and the specialists here take this accuracy thing really personally."
After they had the unit set up and were ready to head back down from the point, though, the fire made a run over the road, blocking their way back. "The road was closed," says Buske. "We discussed whether we should stay up here to monitor it, or whether we should go down into town or go the other way down into the park village. We had six or eight people at the lookout, all of us stuck up here. We concluded that the fire was laying down for the evening and it probably wouldn't get up here on the point till about 10 in the morning. So we figured we'd go into town, be back in time for the morning briefing, and then come up here and pull it out before the fire got here."
"Another option was for us to stay up there with it. There were also several firefighters up here in the area, and they were planning to pull the radio equipment if it was threatened by the fire. They could pull the RAWS for us, too. From the perspective of what the fire was predicted to do, we decided it was better to leave it on site – if they could pull it when they got the radio equipment, that might be best. The one variable was whether the fire would settle down to the south of the escarpment. It might get all the way up here to the point, or it might back down. With a little RH recovery, it would have backed down, but the wind pushed it into an area that was mostly grassy fuels, and then it did a 180 wind switch and pushed up through the drainages."
"It was hot and dry," he says, "with single-digit relative humidity and Haines of about 12 – the indices were three or four degrees over. The Haines goes to certain cutoffs, like the temperature difference between two levels, with the dew point at a lower level. The temperature difference is directly related to instability, and the cutoff for that is a difference of 22 – and what we had was a difference of about 26 – way unstable. The indices went way beyond just exceeding the differences – it crushed them."
"Then the convection column went up about 6 p.m., and it just nuked. It went up to over 40,000 feet – and that was the just the radar reflectivity; it could have actually been another 10,000 feet. We were all watching it grow, a group of about 100 people standing there with their heads up, and traffic was pulling over on the road and gawking at it."
After the briefing at the ICP, he and Buske made the 15-mile drive up to the point where the burned-over unit was. "We found the wind speed and direction were both working," he says, "and there was a little soot on the raws station itself. The cables were melted and fused together. But the unit itself was in pretty good shape; some of the sensors were still working."
She says the winds gusted to 45 mph and then to 60, and there was about another hour of high winds after that. "The wind was coming out of the southwest, and then it flipped 180 to come out of the northeast right before the burnover. The fire was creating the winds. The temperature was around 60º and then that sensor went out. Except for the high winds, the data looked normal. We packed it up and sent it back to Boise. The radio equipment burned up, too, and when we overheard that they'd chartered more repeaters from Boise, we arranged for our replacement weather station to hitch a ride along. We got it the same day."
Barbo says the unit arrived in Boise at 7:30 p.m. on Monday, July 24. "We had been wondering what would happen one of these days if a unit got burned over," he says. "This is the first time it's happened. We had to replace the cables and the fuel stick, but the box and sensors survived well. The unit kept putting out data the whole time. Winds were down to 13 mph at midnight, and the air temperature was 70º with a fuel temperature of 69º and RH at 21 percent. The data didn't change much during the burnover; it was apparently a quick run and a flash."