Whenever wild fires crop up during droughts and threaten to wipe out acres of woods and property everyone wishfully thinks how great it would be if a massive thunderstorm developed and naturally doused the thing.
Has this ever happened?
Or do most threatening wild fires burn out naturally with the help of firefighters?
I don’t know about the rest of the country, but most wildfires here are caused by lightning.
To put out really hot fires you need much greater volumes of water than anything short of a hurricane can provide. A multi-acre wildfire is likely to burn hot enough that any rain reaching the flames would evaporate before reaching the medium.
I do not know that a rain storm has outright doused a serious forest fire into extinction but they certainly slow them down. They cool the fire (making it spread more slowly) and drench materials in front of the fire making them harder to set aflame.
It is interesting to note that forest fires can spawn rain storms downwind from them. A by-product of combustion is water not to mention boiling off all the water in the trees and plants. That stuff goes up in the air and a large fire can toss enough up to cause it to rain nearby.
Wildland fires in the USA are really never declared “out” until there is something called a season-ending event. A summer thunderstorm does not qualify. On the contrary, thunderstorms in the West are often dry, with lots of lightning that starts these fires. It has been my experience that a summer thunderstorm, complete with heavy downpours, has little to no effect on the fires themselves. Instead, summer thunderstorms actually hamper fire fighting efforts.
A season ending event may be best described as continuous rains over a long period of time (think weeks), the possibility of drenching hurricanes (not likely in the West), or cold weather and heavy, sticking snows. Then again, I’ve been on wildland fires as late as October/November, long after the winter snows have started and stayed, yet fires that began months earlier are still active and moving.
Rather than send planes up to douse the fires, wouldn’t it be more sensible to dampen the grass before they’ve been lit? Please tell me this has already been thought of!
No.
29% of the land area of the United States, or ~700 million acres, is forest.
Do you know how much water you’d need to keep that much land “dampened”? (It’d have to be desalinated water, of course- saltwater would kill much of the forest you were trying to protect.)
I bet you don’t, and nobody else does either, but it’s an awful lot.
I suspect you could take every crop sprayer in the Western Hemisphere and fill them all with water and send them off to squirt forest for a week and still not make a dent.
As noted just above wouldn’t work. Would need way too much water and might only slow the fire down.
This is why forest fire fighters do “controlled burns”. Essentially they burn out areas ahead of where they think the fire will go. These are done carefully to make sure they do not make things worse. This produces a fire break. The fire comes to the already burned out spot and with nothing to burn just stops there. Does not always work (fire may shift to an unexpected direction or embers from the fire fly over the fire break and start new fires on the other side and so on).
Remember, forest fires are endemic to forested areas and are to some degree part of the natural cycle.
Every wooded area grows too dense to sustain itself eventually; a fire comes, burns off most of the undergrowth and a lot of the mature trees - some survive even severe burns - and the circle of life can continue, etc.
We can’t even put a man on the moon, and you want engineers to come up with a way to move billions of acre-feet?
Yeah, there are a lot of forested pocket areas along the railway lines here that could use a good burn. But, of course, they’ve gone without fire for too long, and are over grown, and a fire now would be too intense and damage houses and such around the forest. So they have to be thinned by hand first.
I know that they were doing controlled burns in High Park in Toronto to burn out underbrush and non-native species and promote the native ecosystem (oak savanna in that specific location).
Ah, wildland fires are seldom extinguished. They are contained. In other words, a perimeter is created around a fire to stop its spread. Ideally it’s a six foot wide path down to mineral soil. As the containment lines lengthen, other fire fighters expand the width of the line if needed. Eventually a perimeter is established all the way around a fire using natural and artificial barriers. A fire is contained and the news media goes away.
Yet the fire inside the perimeter may continue to burn, smolder, creep, whatever until it runs out of fuel, the weather changes or there is a final season-ending event.
At every opportunity during containment, fire crews enter the burn areas to extend the perimeter. The wider, the better. Back burning within the perimeter. It also includes sending crews into burned areas up to 100 yards (if possible) into the burned areas all along the perimeter to check for hot spots and try to extinguish them. Since water is often scare to nonexistent, that means using dirt and hand tools to stir the ashes, dissipate the heat and mix with mineral soil. This is called mopping up. It’s a dirty, thankless job the media never reports about nor photographs for the evening news. Mopping up is also a rite of passage. Greenhorn fire crews gain their first fire fighting experiences by mopping up. Mopping up is an exercise to separate those who will continue to fight wildland fires and those who say screw this and never again.
Mopping up means you get dirty. Real dirty. Black ash from head to toe dirty. And the best, most effective mopping up is done on your knees with bare hands. I remember my greehorn days spending a full 16-hour shift mopping up. You check for hot spots and when you find then, you kill them. And the only way to check for potential heat is to use your bare hands in the ash. Try and spend two hours on your hands and knees in a 200 square foot area with six inches of ash covering hot spots. All you have is a shovel or a rake. That entire 200 square foot area of yours must be completely bare hands cold to the touch all the way through the ash and timber to mineral soil.
Damping the grass is impossible for two simple reasons. No water, and it’s not grass fires you are seeing on TV from California. Fuel mixtures include grass, chapparrel, woody vegetation, forests, dead and down, etc. Quite a bit of these fuels are bone dry through and through.
Think of a roaring campfire (maybe six feet in diameter) using six inch split logs that have air dried for several years. Get it real hot for at least an hour so all the logs are glowing, even to their centers. Time yourself how long it takes to kill that fire down to cold to the touch with bare hands using as much water as you want. Now multiply that effort by several thousand acres, minus 99.9 percent of the water, add in low humidities, strong winds, and crappy terrain.
Finally, most wildland fires are started by dry lightning, often in inaccessible locations. How do you prevent such fires in the first place by dampening grass (which means nothing in wildland fires, unless we are talking about rangeland grass fires)? Only current technologies of prescribed burning, forest thinning and proper land management may reduce the effects of creating large fires, but it will never eliminate them. However, much of the West has been in drought, going on six, seven, eight, nine years in places.
California is burning and this is only early July. This is a bad sign. If this hold true for the summer, we could have another record year across the West, with money running out real fast and fire crews working beyond exhaustion. Since Congress is loathe to pass any decent legislation for creating a nationwide fire budget, fire costs come out of current (and future) operating budgets of land management agencies. So expect recreation areas, campgrounds and visitor centers to operate on limited hours, if not close, in your national forests and parks, state forest and parks, etc. Not just later this summer but next year as well, even before fire season starts.
Duckster - thank you for that post. It was a real eye-opener.
Since you seem to know a lot about this topic I was wondering if you could shed light on something that has always puzzled me.
Pretty much every year we see footage from the US, Australia and occasionaly southern Europe of millions of dollars of property going up in flames and emergency crews risking their lives to try to protect them, from brushfires which are pretty much guaranteed to happen every few years. I’ve always wondered if it would be possible to build a home that would be fire-resistant, so that you could button it all up, tell the fire crews to concentrate their efforts elsewhere, and be 90% confident that when you came back it would be standing with just some smoke marks on the outside?
Something along the lines of a concrete-block house with window/door shutters covered in ceramic fibre/board insulation, ceramic roof tiles with more insulation underneath, all the utility hookups and so on internal, or underground. Keep the ground for e.g. 15 metres from the house as short grass, with nothing bigger than small bushes for another 15 metres or so beyond that. Make sure everything on the outside of the house is non-flammable and ideally non-conductive of heat.
Would that be feasible, or are the temperatures involved so high that anything short of an inside-out blast furnace will just burst into flames?
The cleared ground is arguably the most important here. In many cases houses like you describe are the only thing standing after a fire. It is done, and it works well. Even basic stucco and spanish tile is going to make for a tough to ignite house with 30-40m of clear ground around it.
The thing to remember as to why so much property goes up in flames
is people focusing on pretty and blending with the scenery. Huge trees shading the house may lighten the power bills in the summer, but it might as well be a giant wick for a house candle with a major fire blowing through.
Those beautiful wood shake roofs are also easily lit, but people keep doing it.
So switching the building codes and insurance standards to require adobe/stucco/brick or whatever houses, along with keeping trees away from houses (use shade sails or whatnot instead) would make life significantly easier for the folks who have to keep the neigbourhood from burning down?
That’s pretty depressing - yet another example of how rare common sense is. You’d sort of hope that in areas where wildfires are common there woul be some planning for it, but I guess not.
As Duckster said, weather only helps dampen wildland fires.
Here is the history of the great Yellowstone fire of 1988.
While the snow did a great deal to contain the fire, the news media made it sound like that first snow extinguished the whole thing, but, in fact, it took another 2 months.
That sort of legislation might work in Britain or Oz, but in the American West, not likely. If you tried to change the fire/building codes to ban ranch houses (and other wood construction) in fire-prone areas people would be up in arms, regardless of the risk.
Personally, I’ve always wondered why on earth wood construction is so common in the US anywhere; here in Florida, for example, homes are divided evenly between wood and concrete block. Little or no brick housing.
And, of course, every time there’s a fire or a hurricane lots of houses go kablooey.
Hmmm. I wonder what the effect would be of a policy along the lines of “build what you like, but we’re not going to protect it for you. And forget about insurance of any kind”.
I’d always assumed that the hurricane thing was down to flimsy houses being cheap to build, and government insurance picking up the tab for replacing them. However, that’s probably a skewed impression from the UK media, who are not exactly world experts on either hurricanes or tropical housing…
Since about 1993 there have been pretty strict hurricane-“proof” building codes, which seem to have worked pretty well. Most of the really serious hurricane/tornado damage is to mobile homes (prefab housing), which of course are not subject to the same standards.
A relatively mild hurricane that does no more than mess up a few roof tiles on “regular” houses can tear an entire mobile home park. Hurricane Andrew in '92 (which was admittedly a “severe” hurricane) did this.
There isn’t really such a thing as “government insurance” for hurricanes, AFAIK. The tab is mostly picked up by homeowners’ insurance. State and/or Federal funds may be allocated to help rebuild after the fact.
We had a major forest fire in February. The fire departments kept structures from catching fire, and also kept the embers from spreading the fires to new sections of land. The actual work of fighting the vegetation fire was left to the forestry people and their plows.
Right now, the Dismal Swamp and the Pocosin Lakes Wildlife Refuge on the south side of the Albemarle sound are burning. The fires are contained as described by Duckster, but with 6 to 9 feet of peat in the ground, the contained fires can conceivably burn well past the new year should we not get a hurricane this year.
Unless, of course, we get another lightning strike, and get a whole new fire going. Which happened this weekend in The Dismal Swamp.