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Yosemite Fire Example of How Droughts Amplify Wildfires

The massive Rim Fire near Yosemite National Park in California is an example of how drought can amplify wildfires in a warming, drying West.

The fire, which now ranks as the 14th-largest wildfire in state history, has been racing through parched stands of oak and pine trees, and threatening some of the region’s iconic giant sequoia trees. The vegetation in the area, and indeed across much of central and southern California, is extremely dry, as the state has experienced its driest year-to-date.

The Rim fire burning in central California, near Yosemite National Park.
Credit: NASA.

California received a record-low 4.58 inches of precipitation during the January-to-June time period. That total was 1.69 inches below the previous mark, set in 1898, according to the National Oceanic and Atmospheric Administration, and nearly 10 inches below average.

A wetter-than-average July in California did little to alleviate drought conditions. Because the state typically receives very little rainfall during the summer, even light amounts of rainfall can push totals above average without putting a dent in the drought.

To make matters worse, a major heat wave in July helped further dry out soils, making forests primed for fire. 

Parts of the West have been warming faster than the rest of the lower 48 states since the 1970s, a trend tied to climate change as well as natural climate variability.  

Anthony Westerling, a climate scientist at the University of California at Merced who studies how climate change effects wildfires, said that increasing temperatures promotes evaporation, which leads to more frequent instances of “extreme fire conditions.”

“We have a lot of background variability from year to year and decade to decade in precipitation and rain and snow,” Westerling said. “But that (increasing) trend in temperature means that you have more evaporation” throughout the seasons, which is “really is exacerbating the natural drought periods.

“These really extreme fire conditions with very, very low fuel moistures become that much more likely over time, even without any change in the frequency of low precipitation years.”

A look at the Rim fire's growth since last Wednesday.
Click image to enlarge. Credit: ABC7News via Twitter

The current tinderbox that is the Central Sierra Nevada Mountain range can be traced back to the winter, when precipitation suddenly cut off.

“This last year we were seriously low on our snowpack in this part of the central Sierra Nevada,” Jerry Snyder, a Stanislaus National Forest spokesman, told Climate Central. The thickness and water content of spring snowpack and the timing of spring snowmelt, in particular, can influence wildfire risk during the summer. “We were only about 58 percent of normal, which meant that things dried out a lot sooner.”

Jeanine Jones, an interstate resource manager with California’s Department of Water Resources, said record precipitation during the first part of the 2012-13 winter helped bolster statewide water supplies enough to allow California to avoid serious water supply concerns this summer. The dry second half of the winter, though, contributed to the state’s wildfire woes, Jones said.

After January, “the faucet shut off,” Jones said. Such a bipolar winter, with little spring snow, may be a sign of winters to come in a changing climate, she said.

Jolyne Lea, a hydrologist with the National Water and Climate Center, said some weather stations at high elevations in the Sierra Nevada Mountains had near record low snowpacks during the 2012-13 winter.

As an example of how little snowpack remained this spring, according to Snyder, summer recreation in some parts of the Stanislaus National Forest began in June, a full month earlier than normal.

Percent of average precipitation so far this year in California.
Credit: NOAA.

“Early snowmelt dried things out significantly all across the forest,” Snyder said. A July heat wave, brought multiple 100°F-plus days to the Stanislaus forest. (That same heat wave caused Death Valley, Calif., to come close to tying its record for the hottest temperature recorded on Earth) “That helped further dry things out,” and pushed fire weather danger very high due to the abundance of very dry vegetation, Snyder said.

“There’s lots of stuff out there available to burn and conditions are right for it, so we’re having a really serious problem trying to corral this fire,” he said.

The conditions that have contributed to the explosive growth of the Rim Fire have become more common across much of the West in recent decades.

In the western states, including California, years with above-average temperatures, reduced spring snowpack, and early snowmelt tend to be years with bigger, longer-lasting fires. Research has also shown a general shift in forest fire ecology across the West, with a significant increase in the number of large, long-duration wildfires in many areas starting in the mid-1980s, a trend that has been attributed to a combination of climate change, land use change, and shifting fire suppression strategies, among other factors.

In the mountains of the Sierra Nevada in particular, decades of government policies to extinguish many natural wildfires rather than letting them burn themselves out have led to a buildup of vegetation, or "fuels," for today's fires to burn. "We do regularly suppress fires allowing only a few natural starts to burn along with prescribed burning for resources benefits," Snyder said. According to data Snyder provided, there were at least five large wildfires since 1973, including the Tuolumne Fire in 1987, which killed a firefighter and was the previous record holder for the largest wildfire in the Stanislaus National Forest. 

History of large wildfires that burned in the same area as the Rim Fire.
Click image to enlarge. Credit: U.S. Forest Service.

There are more large fires (greater than 10,000 acres) burning now than at any time in the past 40 years, and the total area burned each year has also increased. The top eight worst wildfire years since 1960, in terms of acres burned, have all occurred since 2000, according to NIFC data.

According to Climate Central research, in some states, such as Idaho and Arizona, the number of large fires burning on U.S. Forest Service land each year has tripled or even quadrupled since the early 1970s. In other states, such as California and Wyoming, the number of large fires has doubled.

The Rim fire is one of 36 large fires burning across the U.S. as of Tuesday, and firefighting resources are stretched so thin that the nation’s wildfire readiness is at its highest level in five years

However, the number of wildfires and acres burned to date are not unusual in the context of the past decade. So far this year, there have been about 33,000 wildfires in the U.S., according to NIFC data, with 3.5 million acres burned. That compares to a 10-year average of 54,000 fires by this point in the year, with about 5.8 million acres burned. The problem firefighters are facing is that so many large fires have erupted at the same time. 

Many factors are involved in creating conditions that are primed for large wildfires. In addition to warming temperatures and changing snowpack trends, decades of fire suppression strategies have left large tracts of forest with excess fuel to burn. Increased human development near traditionally fire-prone ecosystems has contributed to an uptick in damaging fires, and natural climate and weather variability plays a large role as well. 

Researchers predict that the area burned in the West may quadruple for every additional 1.8°F of average surface temperature rise. That is particularly ominous, since according to the most recent climate model projections contained in the draft U.S. National Climate Assessment, average temperatures could rise between 2°F and 4°F across most of the U.S. within the next few decades, and by as much as 8°F by 2100. The assessment, along with other studies, have projected an increase in drought frequency and severity in parts of the West, particularly the Southwest, which has benefited from an active summer monsoon season this year.

Related Content
Wildfire Alert Heightened As Blazes Char Western U.S.
5 Must-See Charts From Major New Climate Report
Ongoing Coverage of Historic Drought in U.S.
The Climate Context Behind the Deadly Arizona Wildfire
Rising Temps, Shrinking Snowpack Fuel Western Wildfires
Western Wildfires


By mememine69
on August 26th, 2013

A scientific consensus of “maybe” is unsustainable not
unless the scientists end the debate to save the planet and finally agree it will be an inevitable and eventual crisis. They refuse to say this.

Science’s consensus of “maybe” funds and feeds the deniers more than all of big oil’s money in the world so deniers and believers can agree on one thing; this costly debate will end when science changes their consensus of “could” to a consensus “inevitable” and finally shut down the denier machine. Since science isn’t saying a crisis will happen why are we saying it to our children? Who is the neocon again here?

What has to happen now for science to agree it will happen
now, not just might happen; complete unstoppable warming?

Reply to this comment

By Bryan Bates (Burlington Ontario Canada)
on August 26th, 2013

When are people going to understand that carbon is very were you see It is very small and very light in wieght. All I have come up with a little formula that I follow, its stop pollution from happening made things stronger, destroy things and end the usage of landfills. You burn things up it does cause pollution, now stop it please I want to live.

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By Eric Peterson (Front Royal, VA 22630)
on August 27th, 2013

The 1000+ acre wildfire numbers (red bars in the last chart) are partly a result of Forest Service policy.  That policy switched from a complete focus on fire suppression to letting forests burn under controlled and sometimes uncontrolled conditions, see & Ruth.pdf Controlled burns can also turn into wildfires.

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By Ethan (Cameron Park/California/95682)
on August 27th, 2013

It would be interesting to see a plot of board feet of timber harvested by the USFS against the annual fires over 10,000 acres - similar to the plot above.  I’m not sure, but I suspect there would be an inverse correlation. The USFS used to thin forests through timber sales - now only limited numbers of timber sales are conducted for forest health each year.  The USFS actually used to make money from the sale of timber as well - which would go a long way to helping their ever-present lack of budget.  While the drought this year has certainly made conditions for catastrophic wildfire ripe, a properly managed forest may have reduced the scale and intensity of the Rim Fire.  Forest management must include controlled burns and timber harvests, otherwise our forests will continue to go up in flames.  Why not take advantage of one of our great renewable resources rather than watch it go up in flames or succumb to insect and disease.  How much carbon has this fire put into the atmosphere?  Its long past time for a national debate about forest management.

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By Bill McEwen (Yucaipa, CA. 92399)
on August 28th, 2013

As this trend continues, as we lose more and more of our mountainous watersheds in the West, we’ll certainly lose a great deal of our water resources and our hydroelectric clean energy generation capacity.  As the Keeling curve continues on its upward trajectory, with higher and higher concentrations of CO2 in our atmosphere, this destabilization will impact more than our mountain ecology; it’ll have severe impacts and implications for civilization in the West, for instance, in California, home to over 38 million people.  Where will our drinking water come from when the watersheds are all burned up and there is little snow and tons of mud?  What’ll happen to California agriculture?  What will happen to people?

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By richard wineberg (60625)
on August 29th, 2013

Prescribed controlled burns and thinning, as Ethan suggests is critically important…

Like the Native Americans discovered, non-fire season fires reduce fuels, space trees, and favor fire dependent species.
Not to mention increased game populations…

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By David
on August 31st, 2013

Please show a long term chart of percipitation for Calif.  (I did not see one.)  The US as a whole has had a slight increase in percipitation, so any local drought does not indicate “global” warming” but normal regional patterns.  Recently the PDO has shifted to its cold phase, ( La Ninas dominate) and this likely affects Calif percipitation,  Likely forest management is the largest factor here.

I would not worry about the IPCC what if projections.  All climate models show T increasing more then it has, (They are all wrong) a clear sign that climate senstivity to CO2 is much lower then they think.  The world has not warmet for over sixteen years.  Hurricanes are not increasing, and according to the PMDI (Palmer drought index), either are droughts.  This year the NH ice has increased about 70 percent above last year, and SH sea ice has been increasing for thirty years.

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By Jean Zlotkin (san juan bautista, ca 95045)
on September 1st, 2013

good, complete, and helpful article for presentations for Climate Reality. org and teaching high school students about global warming. thanks.

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By Daniel Ferra (Palm Springs)
on September 4th, 2013

What happens if the Southwest drought does not end soon ?

Will we keep using 3 to 6 million gallons of Clean Water per Fracked well, to extract natural gas ?

This petition will ask the California Regulators and Law makers to allocate Renewable Portfolio Standards to Ca. home owners, the RPS is the allocation method that is used to set aside a certain percentage of electrical generation for Renewable Energy in the the State.

The State of California has mandated that 33% of its Energy come from Renewable Energy by 2020.

The state currently produces about 71% of the electricity it consumes, while it imports 8% from the Pacific Northwest and 21% from the Southwest.

This is how we generate our electricity in 2011, natural gas was burned to make 45.3% of electrical power generated in-state . Nuclear power from Diablo Canyon in San Luis Obispo County accounted for 9.15%, large hydropower 18.3%, Renewable 16.6% and coal 1.6%.

There is 9% missing from San Onofre and with the current South Western drought, how long before the 18.3% hydro will be effected ?

Another generator of power that jumps out is natural gas, 45.3%, that is a lot of Fracked Wells poisoning our ground water, 3 to 6 million gallons of water are used per well. If Fracking is safe why did Vice Pres Cheney lobby and win Executive, Congressional, and Judicial exemptions from:

Clean Water Act

Safe Drinking Water

Act Clean Air Act

Resource Conservation and Recovery Act

Emergency Planning Community Right to Know Act

National Environmental Policy Act

“Americans should not have to accept unsafe drinking water just because natural gas is cheaper than Coal. the Industry has used its political power to escape accountability, leaving the American people unprotected, and no Industry can claim to be part of the solution if it supports exemptions from the basic Laws designed to ensure that we have Clean Water and Clean Air” Natural Resources Defense Council

We have to change how we generate our electricity, with are current drought conditions and using our pure water for Fracking, there has to be a better way to generate electricity, and there is, a proven stimulating policy.

The Feed in Tariff is a policy mechanism designed to accelerate investment in Renewable Energy, the California FiT allows eligible customers generators to enter into 10- 15- 20- year contracts with their utility company to sell the electricity produced by renewable energy, and guarantees that anyone who generates electricity from R E source, whether Homeowner, small business, or large utility, is able to sell that electricity. It is mandated by the State to produce 33% R E by 2020.

FIT policies can be implemented to support all renewable technologies including:
Photovoltaics (PV)
Solar thermal
Fuel cells
Tidal and wave power.

There is currently 3 utilities using a Commercial Feed in Tariff in 3 Counties in California, Los Angeles, Palo Alto, and Sacramento, are paying their businesses 17 cents per kilowatt hour for the Renewable Energy they produce, under the Feed in Tariff. We can get our Law makers and Regulators to implement a Residential Feed in Tariff, to help us weather Global Warming, protect our communities from grid failures, and generate a fair revenue stream for the Homeowner, but we have to over come some obstacles.

The State has mandated that we get 33% of our electricity from Renewable Energy (RPS), seems like we should be sharing this 33% pie, utilities, third party leasing companies, and the large energy companies who mostly build out in the fragile desert eco-systems, all fight over that 33% pie, and what about the Law abiding, Tax paying, Homeowning, Voting Citizens, why are they left out of the Renewable pie sharing ?

Here are some of the reasons and a look as to why it is better to own your own Renewable Energy System.

All Three leagues have a piece of the pie, but there is 4 to 8 teams in each league that want a piece of that carve out money pie, causing huge infighting, and as of right now the homeowner is left out of the ballgame, with no chance of eating the all american pie, why? because we are not represented at the Renewable Portfolio Standard dining hall, with a chair at the pie sharing table.

“The benefits of owning a renewable energy system far outweigh the benefits of a lease or a power purchase agreement (PPA). Under the American Recovery and Reinvestment Act of 2009, homeowners are eligible for a federal personal income tax credit up to 30% of the purchase cost of their renewable energy system, without a maximum limit.** Homeowners can utilize the incentive money in any way they choose. But homeowners that choose to lease their systems turn over their rebates and incentives to the third party lease or PPA companies associated with the solar systems installed on their homes.”

“The owner of a renewable energy system is also sheltered from rising electricity costs, which have historically increased on average of 3-5% each year. This presents homeowners with opportunities to save money each month on energy and also reduces their reliance on third-party utility companies. By purchasing a renewable energy system with cash or through a loan, a homeowner can completely pay off his or her system and then independently produce clean energy.

By choosing a lease or a PPA option homeowners are essentially substituting their utility companies with third-party leasing companies. Additionally, homeowners will likely be required to purchase their systems, renew their leases, or have the systems removed from their roof and revert to paying utility rates once their leases have ended.” Charlie Angione.

“There’s absolutely no such thing as a $0 down solar lease or PPA and here’s why. A requirement of both of these financing programs is that you agree upfront to give the leasing or PPA company your 30% federal tax credit which is worth thousands of dollars as well as any other financial incentives.

At $5.57 per Watt. a 6 kW solar system would yield a federal tax credit of $10,026!

With a $0 down loan instead of a lease, you’ll get to keep the 30% federal tax credit as well as all other applicable financial incentives for yourself and you’ll own your solar system instead of renting it, for a much greater return on investment.

And if you do decide to lease instead of own, good luck ever selling your home with a lease attached to it. What homebuyer will want to purchase your home and assume your remaining lease payments on a used solar system on your roof, when they can buy and own a brand new system for thousands less.” Ray Boggs

We also need to change a current law, California law does not allow Homeowners to oversize their Renewable Energy systems.

Japan, Germany, and our state of Hawaii, will pay residents between 13 - 37 cents per kilowatt hour, here in California they will pay a commercial FiT in a few counties at 17 cents per kilowatt hour, No Residential FiT and they wont let us oversize our Residential Renewable Energy systems.

Campaign to allow Californian residents to sell electricity obtained by renewable energy for a fair pro-business market price. Will you read, sign, and share this petition?

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