Meteorologist at Weather Underground, background in fire weather research. Twitter: @WunderKari
By: kiefer, 3:05 AM GMT on June 21, 2012
Today was the first experiment of its kind. Experimental burns for fire-weather interactions and fire behavior are usually performed during prescribed burns on flat terrain. Prescribed burns are a useful fire management tool to maintain low fuel (or less vegetation). If a wildland fire develops, the fire would have less fuel to consume and thus would not be as intense. Prescribed burns are rarely performed on hillsides, canyons, and valleys because complex terrain creates difficult fire management. Why you ask? Well fire spreads much more rapidly on slopes.
Upslope flow develops in the daytime due to daytime heating (the sun shines on the ground, warms the ground and the air above the ground, and warm air rises), which results in warm air that rises up and out of a canyon or valley. This upslope breeze will push a fire front further up the hill. Also, the fuels along that slope get preheated because the flames are closer to the fuel on the uphill side. The grass and shrubs are at an angle to the flames, and thus closer to the flames. They get preheated by radiant heating and ignite quicker than fuels next to flames on a flat surface. At the same time, convective heating pulls cooler air in from behind the fire front as heated air rises further upslope. Thus, the draft strengthens and increases the rate of spread. In summary, fires generally spread and grow faster upslope than on flat terrain. This is why fire management is problematic in complex terrain. Since it is so difficult to manage and contain, it is difficult to study. The SJSU Fire Lab was lucky enough to set up such an experiment with the help of CALFIRE. Many of the hillsides and valleys at the Fort Hunter Ligget Army Base are under prescribed burning this week. And they have sufficient firefighters to take care of any problems, in case one of the burns gets out of control.
Picture of hillside to be burned. Towers equipped with various meteorological instruments.
Upwind of the burn site sits a 105 ft tower to measure ambient conditions.
A piece of grass I broke in half to show how dry the fuels were. This dry grass stood about 4 feet high.
Picture just after ignition with drip torches along fire road.
Picture of flames once the fire front reached taller and thicker fuels. Must have been 20 foot flames!
We saw multiple vertical columns of smoke and flames. This rarely occurs on flat prescribed burns, but with this complex terrain, the fire front did not stay in a straight line and circular air patterns developed.
My new fire gear!
By: kiefer, 10:42 PM GMT on June 12, 2012
I am officially fireline qualified! You would think I have already been though this training, since I have been around multiple prescribed burns. However, it was not a requirement because most of those burns were on private land in rural Georgia. I would like to be apart of some upcoming experiments with the Fire Lab at SJSU. Most of their upcoming experiments are in California, and so CAL FIRE asked us to get fireline trained. After 2 online courses and 1 8-hour field day, I can go to any prescribed or wildland fire!
Field Day: 8 hours on Saturday
Does anyone recall the temperatures in the Bay Area this weekend? Yikes. Hot day to wear all that fire gear over regular clothes, with a helmet and goggles.
9 am: Introductions
3 students from SJSU Fire Lab
3 volunteer firefighters in training
4 volunteer firefighters to help out with training
2 firefighter educators
12 people total
10 am: Fire Shelter Training
Otherwise known as "The Burrito".
This is an image of the New Generation Fire Shelter designed by The National Interagency Fire Center in Boise, ID. This shelter is credited with saving 14 lives since its introduction in 2005, and is made from an outer layer of woven silica laminated to aluminum foil with an inner layer of woven fiberglass material, also laminated to aluminum foil. The side that faces down is open to the ground, and you use your arms, legs, and feet to hold down the edges.
We train to deploy the shelter from it's casing under 25 seconds. There are two methods of deployment: the standup or the sit down. Once you get in it, you lay down on your stomach with the burrito draped over your back. Your feet are toward the fire and your head is the farthest away from the fire. You clamp down tightly with your feet, legs, and arms so the strong winds along the firefront don't rip the shelter off your body. You can even bury a hole in the ground so you have more oxygen. You may be in this thing for 45 minutes to an hour, so make sure to bring your water bottle in there with you. Keep all things flammable outside! The idea is you want to be able to get this thing out and get into it as fast as you can no matter what the circumstance. We were timed as part of the training. My time was an impressive 17 seconds! The firefighters at the training have never had to deploy a fire shelter. This is a LAST resort if you cannot get to your safety zone and away from fire.
This is an image of the fire shelter folded up in it's case. All people on the fireline carry this on them at all times!
11 am: How to make a Fireline
A fireline is part if a control line that is scraped or dug to mineral soil and is a barrier used to stop the spread of fire by removing fuel. The width of the fireline is one and a half times the height of the fuels (grass or vegetation). We dug two firelines in a group of 5 people: one in low fuels (grass) and one in thick fuels (6 foot weeds). This was hard work. Each had a Pulaski, McLeod, or shovel to dig out roots, stems, and cut logs and overhanging braches and limbs. We dug for an hour and didn't get far. I can't imagine doing it all day in those conditions with all that gear on...
Whew--we get a break!
1 pm: Firing Devices
Its hard to believe how many flammable devices firefighters carry. But firefighters fight fire with fire. If you burn the vegetation ahead of the firefront, then the fuels are consumed and the fire will not continue in that direction. So firefighters carry fusies, drip torches, matches, and lighters.
Image of standard fusies, similar to road flares.
We learned how to open and close an (empty) drip torch. We were not allowed to light anything on fire because much of California was in a Red Flag Warning. I'm sure we wouldn't have risked it even if we weren't in high fire danger!!!
Image of a standard drip torch.
2 pm: Hose Lays
Simple and Progressive hose lay techniques.
Simple is one long hose and you spray the fireline as you walk with the hose. Progressive is where you clamp off the hose and add another hose when you run out of length, also spraying along the fireline as you go. This was the coolest part of the training! I got to carry the hose and shoot water all over the place. It wasn't as heavy as I thought it would be, but it helped that a person is required to walk behind the person with the nozzle and help them with the weight of the hose.
We also got to play with a back pump. It's a backpack that holds up to 5 gallons of water and weighs up to 40 lbs. It was very heavy but very cool because it reminded me of a serious Super Soaker! I miss those things!
4 pm: Clean up and closing.
Lots of clean up was required after all this training...
The worst part about the training: Folding the fire shelter up and rolling the hoses up. I guess I don't like the clean-up?!
I'll post videos/pictures/blogs of prescribed and wildland fires I will try to get to this summer.
The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.