Wildfire 101: Ignition

Since 2001, each wildfire season has averaged almost 73,000 ignitions and over 6.5 million acres burned in the U.S. Interestingly, the vast majority of these ignitions are human-caused, but the total acreage burned is mostly accredited to lightning-starts.

Annually-collected statistics on ignitions show that 85% of all wildfire starts this century have been classified as human-caused. Wildfire modeling studies point to higher ignitions due to predictable patterns of human activity along transportation routes, in recreation areas, and during certain times of year. Arson, automobile brakes, campfires, engine sparks, and escaped debris fires are the most frequent types of human-caused ignitions. 

Ignitions_Map.png

RedZone’s compilation of 2015 Wildfires Igntions

Though lightning and other natural causes make up most of the other 15% of annual ignitions, they cause 62% of the total acreage burned. This discrepancy is due to the fact that fires that start naturally often occur in large forested areas with more fuel and limited accessibility, and are likely given less suppression effort since naturally-occuring fire helps maintain ecosystem health.

 

graph.png

All statistics are based on fires and acres reported to the National Interagency Coordination Center at NIFC.

NASA’s JPL announces plan for more advanced wildfire detection by 2018

NASA’s Jet Propulsion Laboratory (JPL) has been refining a concept first proposed in 2011 for a network of space-based sensors called FireSat that would revolutionize the monitoring coverage of wildfires globally.

 

JPL's rendering of FireSat in action

According to the JPL, “FireSat would be a constellation of more than 200 thermal infrared imaging sensors on satellites designed to quickly locate wildfires around the globe. The FireSat sensors would be able to detect fires that are at least 35 to 50 feet (10 to 15 meters) wide, within an average of 15 minutes from the time they begin. Within three minutes of detecting a fire from orbit, FireSat would notify emergency responders in the area of the fire, improving support for time-critical response decisions.” Currently MODIS and VIIRS satellites (which both serve many other functions than fire detection) operated by NASA have fire detection capabilities but are limited to large image sizes and can only detect fires twice a day. FireSat sensors would complement these systems by enabling faster, nearly continuous communication with the ground by sending low-resolution images of detected fires every minute along with a latitude and longitude of the location.

 For more on this and other stories from NASA’s JPL visit the JPLNEWS page.

California’s Fire Potential Outlook for December

 

Dec2015OutlookMap.png

 

Southern California:

Normal significant wildland fire potential is expected for Southern California for the outlook period.

Weather and Fuels:

After a relatively wet early October, the weather over much of the area turned warmer and drier during the second half of October and into November. A strong ridge of high pressure over the Eastern Pacific kept the storm track well to the north. At the same time, several troughs to the east of the state allowed periodic offshore wind episodes to occur. Most of these were of light to moderate intensity and of short duration. Some wetting rains and high elevation snowfall occurred over portions of Central California, but most of Southern California saw little precipitation during the second half of October into the first half of November. The combination of offshore winds and warm ocean temperatures pushed many locations across Southern California into monthly maximum temperatures records. Fuel conditions vary from seasonally wet to extremely dry across the area. Most of the Sierras and higher elevations of the mountains of Southern California have seen several significant precipitation events, and with the short daylight hours and low sun angle, it would be difficult for these areas to see any additional significant fire activity this year and into early 2016. However, the dry weather allowed for a recent grass crop to cure across portions of Southern California. In general, eastern Santa Barbara County southward to Orange County are the driest parts of the area. These areas continue to see very low dead fuel moisture due to the very warm and dry weather.

Long range models depict a change in the weather pattern over the next few weeks. A much more progressive pattern seems to be shaping up over the Pacific. Additionally, the El Niño over the Eastern Pacific is likely peaking in intensity. As the east to west trade winds continue to weaken and convection increases across areas of the Eastern Pacific, storm frequency should increase in December. Significant and potentially heavy rain will accompany some of these storms. Large fire potential should be near normal early in December over the remaining dry areas.

Northern California:

Normal significant wildland fire potential is expected for Northern California for the outlook period.

Weather and Fuels:

November precipitation ranged from 50 to 125 percent of normal over most of northern California, with temperatures that were near normal to 5 degrees below normal. This helped get the early phases of a high-elevation snowpack get started. Fire Danger / Potential was down to near zero in the Northwest quarter of the Geographic Area and the roughly once-per-week storms elsewhere, each with light to moderate precipitation, sufficiently to greatly reduced fire potential.

For December, near-normal precipitation is expected, with temperatures near to a little above normal. The strongest El Niño in 18 years will affect the jet stream patterns, such that it is expected that northern California will have a good chance of receiving above normal precipitation for the three month period from January through March. Higher elevation snowpack should be the best in at least the past several years, and mid-elevations will see some snowpack (in contrast to the past two winters when there was very little).

http://www.nifc.gov/nicc/predictive/outlooks/monthly_seasonal_outlook.pdf
 

Top Ten Things You May Not Know About Wildland Fires

 

1) 90% of wildfires are human-caused

Sources of anthropogenic wildfires are most often accidental ignition by campers, hikers, or garbage/debris burns…but some are purposely started by arsonists..

2) But the majority of acres burned comes from lightning ignitions

Because they often occur in isolated locations with limited access, lightning fires burn more total acres than human-caused starts. The average 10-year total of U.S. wildfire acres burned by human cause is 1.9 million acres; 2.1 million acres burned are lightning caused. If a lightning fire is not endangering life or property, the US Forest Service will allow the fire to burn under the Fire Use Guidelines.

3) Prolonged drought plus a freeze event can prompt wildfires in non-typical seasons. 

When a freezing weather event hits a wildfire-prone area during drought conditions, it can dry fuels to the point of extreme ignitability. Despite low temperatures, wildfires can frequently still burn when these conditions exist. 

4) Aircraft don’t put out the fire, they slow the rate of spread

Though news outlets heavily cover firefighting aircraft during a wildfire, the retardant these planes drop will rarely extinguish the flames. The retardant is designed to slow the fire’s rate of spread so as to allow ground forces enough time for a direct attack. Retardant is a fertilizer-based product that is able to adhere to vegetation, requiring more heat for ignition. The fertilizer is colored red for higher visibility to tanker pilots to see where the last drop was placed.

5) Smoke color depicts fire fuel types

Smoke is the biproduct of the fuels it is burning, and the color of the smoke is often used as an indicator to firefighters of the type and density of the fuels that are involved. White smoke generally indicates light flashy fuels such as grass or twigs. Thick black smoke indicates heavy fuels that are not being fully consumed. At times thick black some can be an indicator that a manmade substance is burning such as tires, vehicles or a structure. Grey smoke can indicate that the fire is slowing down and running out of materials to burn.

6) The Story of Edward Pulaski

Edward Pulaski was a Forest Ranger in Wallace, Idaho, and is most known for saving the lives of 40 men during the Great fire of 1910. When the fire broke out of control and overwhelmed his crew, he directed his men into a cave and held them at gunpoint so they wouldn’t leave. After the fire had passed, the men came to the entrance to find the ranger covered in debris and thought he was dead. Pulaski arose and stated “Like hell I am.” A firefighting tool pulaski tool he designed was later named after him and is still used today.

7) Post-wildfire mudslides are common

A fast-moving, highly destructive debris flow can occur within a few years after wildfires scorch the soil and roots of vegetation in a particular area, especially in steep terrain. Most occur in response to high intensity rainfall events and are particularly dangerous as they sometimes happen with very little warning.

8) Peshtigo Fire in 1871 killed over 1,200 people

On October 7th, 1871, the most devastating US wildfire started in Peshtigo, Wisconsin. 1,200 people were confirmed killed and the entire town of Peshtigo was destroyed. The fire started when several small burns grew out of control due to high winds. The fire eventually burned over 1.2 million acres. This is the highest recorded death total for a wildland fire.

9) Wildfires are important for the forest ecosystem

Forest ecosystems depend on wildfires to thin the forest canopy allowing saplings near the forest floor access to sunlight. Some plants and trees require fire and heat in order for their seeds to germinate. Fire can eliminate certain plants while allowing fire-resistant species to survive and thrive.

10) Large wildfires are capable of creating their own localized weather

Wildfires generate their own winds as they grow in size. These winds will pull air into the fire as they burn more fuel. Intense heating of air from the surface induces convection, which causes an air mass to rise above the fire and, in the presence of moisture, can form pyro cumulus clouds.

 

Sources include: The History Channel, Wikipedia, Accuweather, Smokey Bear, USGS, about.com, & Spokane Chronicle

 

What Warrants a Red Flag Warning from the National Weather Service?

Another Red Flag Warning was issued for Southern California late last week for very low humidities and strong offshore winds. But what factors actually warrant this official notice from the National Weather Service and what do the associated weather conditions mean?

A Red Flag Warning is used by the National Weather Service to inform area firefighting and land management agencies that conditions are ideal for wildland fire combustion and rapid spread. Specically, the warning denotes a high degree of confidence that weather and fuel conditions meet the ‘Red Flag Event’ criteria in place for a given fire weather zone. These criteria involve low relative humidity, strong winds, dry fuels, or any combination thereof.

According the the NWS, a Red Flag event is verified when the weather and fuel conditions are met simultaneously for any three hour period, and the warning remains in effect until the critical fire weather pattern ends. The characteristics of fire weather zones differ greatly across wildfire-prone areas.  Therefore the specific thresholds needed to meet the warning criteria can vary as well, based on the local vegetation type, topography, and distance from major water sources.  

RFW_map_title.png

 Southern California’s Ventura and Los Angeles Counties had a Red Flag Warning in effect for below 15% RH and gusty winds.

 

Red Flag Warning Criteria From Regions of California.

(source: SoCal GACC) http://gacc.nifc.gov/oscc/predictive/weather/myfiles/Watches_and_Warnings_for_California.htm

Area Description

NWS Fire Weather Zones

Criteria

Southern California desert area excluding the Colorado River Valley

226-228, 230, 232, 260­, 262

Relative Humidity  ≤ 15% and wind gusts GTE 35 mph for 3 hours or more

Colorado River Valley

229,231

Relative Humidity ≤ 15%, with sustained winds (20 foot) ≥ 20 mph and/or frequent gusts ≥ 35 mph for 3 hours or more

Antelope Valley and SE Kern County Deserts

298, 299, 259

Relative Humidity ≤ 15% and sustained (20-foot) winds ≥ 25 mph for a duration of 8 hours or more

Southern California from mountains westward

234-258, 288-297

Either
Relative Humidity ≤15%, with sustained winds ≥ 25 mph and/or frequent gusts ≥ 35 mph (duration of 6 hours or more)

Or
Relative Humidity ≤ 10% (duration of 10 hours or more) regardless of wind

Northern California East of Cascade/Sierra Crest and Western Great Basin including the Modoc Plateau

214, 270-273, 278, 284, 285

Tahoe Management Basin: Three hours of wind gusts ≥ 30 mph and Relative Humidity ≤ 20%

Other Regions:
Three hours of wind gusts ≥ 30 mph and Relative Humidity ≤1

 

The DC-10 Very Large Air Tanker (VLAT)

Aerial firefighting involves the use of aircraft–both fixed-wing and rotary-wing–to combat wildfires. Among the fixed-wing type are air tankers and water bombers equipped with tanks that can be filled with fire retardant or water. Some air tankers (like the DC-10 VLAT pictured below) are loaded on the ground at an air tanker base, while other aircraft (such as the Bombardier 145 “Superscooper”) can be loaded by skimming water from lakes, reservoirs, or large rivers.

The DC-10 VLAT is a converted McDonnell Douglas DC-10 commercial airliner. It’s a three-engine, wide-body aircraft that was first introduced in 1971 and was in service with American Airlines, Hawaiian Airlines, and Pan Am. Production of the DC-10 ended in 1989 and the aircraft flew its last commercial flight in February 2014.

In 2002, the company 10 Tanker Air Carrier began proof-of-concept testing of the DC-10 VLAT in an aerial firefighting role. In 2006, the aircraft was issued a Supplemental Type airworthiness certificate by the FAA which allowed it to be modified for aerial firefighting. Shortly thereafter, the DC-10 VLAT was certified as an air tanker by the United States Forest Service and was first used in California during the 2006 wildfire season on a “call-when-needed” basis at the price of $26,500 per flight hour.

The DC-10 VLAT is not used on all fires as it is operationally limited due to its time to reload retardant and refuel at air tanker bases. However, one retardant drop from the DC-10 covers a swath roughly 300 feet wide and one mile in length, four times the coverage of any other tanker currently in use.

 Aircraft Specifications:

  • Cruising speed:  520 knots
  • Feet-per-minute climb rate:  2,000
  • Fire suppressant tank capacity:  11,600 gallons

**DC-10 VLAT during a demonstration for LA County Fire officials in 2006**

What Happens To Plants After A Wildfire?

News regarding large wildfires typically covers the location of the fire, the size of the fire, and the fire’s impact on people and property. With the possibility of hundreds of homes destroyed, thousands of people displaced, and millions in damaged property, it’s no wonder much of the media’s attention of large wildfire events is focused on what happens DURING a fire.  But what happens after a wildfire is out?  Or specifically, what happens to plants and vegetation after a wildfire burn? Does the ground remained scorched, forever void of life like some scene out of Mad Max?

The truth is wildfire has helped to shape California’s vegetative landscape for thousands of years. It affects the kinds of plants growing in a particular area, their abundance, size, health, and lifespan. The fire kills some plants, rejuvenates others, and some plants may even need fire in order to thrive.

Some areas in Southern California have plants with leaves naturally coated in flammable oils that encourage a fire to spread. The heat from the fire causes their fire-activated seeds to germinate and the young plants can then take advantage of the fact that the other surrounding plant life was destroyed in the fire. The cones of the Lodgepole Pine are sealed with a resin that is melted away by fire, which then causes the seeds to be released. Other plants have smoke-activated seeds which function in a similar manner. Some trees, like the giant sequoia tree, rely on wildfires to make gaps in the vegetation canopy so that sunlight can reach the forest floor allowing their seedlings to grow.  

This map (courtesy of the Department of Agriculture, Forest Service) shows the effects of wildfires on plant life in various regions of the US. The color coding shows the different ecosystem types and the frequency of fire (and types of fire) that allow those plants to thrive.

Some key definitions (courtesy of the Department of Agriculture):

Understory Fire

A fire in forests or woodlands that is not lethal to the dominant, overstory vegetation and thus does not change stand structure substantially. Most (75%) of the dominant vegetation survives.

Mixed Severity Fire

A fire that causes partial (26-75%) replacement of the upper canopy layer.

Stand Replacement Fire

A fire that kills all or most of the living upper canopy layer and initiates succession or regrowth.

Recent Surge in Texas Fire Activity Despite Historic Rainfall in May

Though Texas saw record rainfall in the month of May, fire season is still in full swing. South Central Texas in particular has seen a significant surge in wildland fires. In the last seven days, there have been 268 fires reported with 12,911 acres burned. The largest of these fires was the Hidden Pines Fire in Bastrop County which consumed 4,582 acres and destroyed 68 homes.

Why has Texas seen an increase in fire activity in recent weeks? A wet spring brought significant grass growth to much of the region. Since June, temperatures have been normal to slightly above normal, while relative humidity levels have been below normal. This has allowed new grass growth to become very dry and prone to ignition. Dry grass can be ignited by the smallest of heat sources such as vehicle exhaust pipes, emergency flares, and cigarettes. Once grass has started to burn, it can rapidly spread to surrounding vegetation and structures. These fast moving grass fires become difficult for firefighters to contain due to their rate of spread and unpredictability. Fortunately, weather forecasts are predicting cool and rainy conditions for the next several days, allowing firefighters a much needed break.

https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/06/01/record-breaking-may-rainfall-in-texas-and-oklahoma-by-the-numbers/

NIFC’s Wildland Fire Outlook

At the start of each month, the National Interagency Fire Center (NIFC) produces a 3 month significant wildland fire potential and weather outlook for the entire country. The Wildland Fire Potential map shows a national picture of the expected trend for fire activity and growth based on previous fire history and current weather predictions. This information is used by Fire Managers to determine staffing levels, anticipate large fire growth, and prepare for the need for pre-positioning out of area resources.

month1_outlook.pngBased on the current forecasts from NIFC and the drought conditions, October will likely bring above normal potential for wildland fires in California. This time of year also brings the potential for Santa Ana wind events over Southern California. Much of the nation will see normal to below normal fire potential, due in part to the significant rains that have impacted much of the country in the last week.

To see the NIFC Significant Fire Potential predictions for the months of November and December, click the link below.

http://www.predictiveservices.nifc.gov/outlooks/monthly_seasonal_outlook.pdf

Sundowner Winds and Their Impact on Fire Behavior

A sundowner wind is an offshore northerly Foehn wind that occurs near Santa Barbara, California. The winds surface when a ridge of high pressure is directly north of the area, and they blow with greatest force when the pressure gradient is perpendicular to the axis of the Santa Ynez Mountains which rise directly behind Santa Barbara. These winds often precede Santa Ana events by a day or two, as it is normal for high-pressure areas to migrate east, causing the pressure gradients to shift to the northeast.

 

Sundowner winds are dried and heated by the warm inland valleys and deserts. As narrow canyons and valleys compress the winds, they become stronger and overpower the diurnal winds. Firefighting efforts during a sundowner wind event can become extremely difficult. The Jesusita fire in May 2009 burned 8,733 acres and destroyed 80 homes while damaging 15 more. Most of the destruction occurred while sundowner winds pushed the main fire through populated areas. The Painted Cave Fire during June 1990 rapidly grew to 5,000 acres, destroying 427 buildings and killing 1 civilian.