Texas’ Significant Wildfire Potential

According to Texas Forest Service’s Dispatch Tracker, the weekend produced multiple red flag warnings and 20 new fires totalling over 1,700 burned acres in the State of Texas. Despite the weekend’s elevated fire weather conditions and activity, Texas’ wildfire potential remains normal to below normal into early summer.

 

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February’s Significant Wildfire Potential

WILDFIRE POTENTIAL OUTLOOK FOR TEXAS 

Normal significant wildland fire potential and some areas of Below Normal significant wildland fire potential are expected for the state through May.

Weather & Fuels:

In January, the Plains states, from Texas to North Dakota, were very dry with generally less than 50 percent of normal precipitation for the month. But El Nino conditions and the expected jet stream path are forecast to bring above average precipitation and below average temperatures to most of the state into early summer. As a result, fuel moistures are projecting to remain above critical levels except for a few seasonably typical periods of low humidity, winds, and warm temperatures creating brief elevation of initial attack potential. All indications from Predictive Services (NIFC) point to these brief periods of elevated potential as the dominant concern for significant fire activity for the area in the coming months.

Source: NIFC Predictive Services (Outlook PDF)

 

Fuel Reduction Practices and Purpose

The practice of hazardous fuel reduction is most often associated with moderating the flammable vegetation around the defensible space of individual homes and communities. But this proactive approach to fighting wildland fire comes in many other forms and, unlike fire-fighting in most areas, is a year-round practice. 

 

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Ridgeline fuel break example on the left and a road brushing/shaded fuel break on the right.

The basic function of a fuel-break is to impose some obstacle to the spread of potential fire, and also to provide access to the fire should one break out. Fuel breaks are designed to change the behavior of a wildfire by reducing the quantity, density, and configuration of potential fuels that the fire encounters when it enters the fuel break. 

Breaks are constructed for a number of purposes:

  • To act as a barrier to control the spread of a fire to a particular area or property.
  • To contain the spread of a fire from a fire source.
  • To break up large fuel areas (i.e. where fire may spread rapidly or be difficult to control, a system of firebreaks is sometimes established to aid in confining the fire to a relatively small area).
  • Reduce a crown fire to a fire burning on the ground. 

Fuel Breaks are most effectively located in the following areas:

  • Along ridges, where fires naturally slow their progress under most conditions.
  • 100 feet to 200 feet around structures, where fires are likely to start.
  • Along roads, power lines, and pipelines, where openings already exist.
  • Around wet areas, rock outcrops, mined areas, and other topographically strategic locations where fire spread may be reduced.
    • Adjacent to areas where fuel reduction treatments, such as thinnings and surface fuel treatments, have already been performed, where fire intensity and spread are already reduced.
    • Connecting to existing fuel breaks, to expand protected areas in a systematic way.

Natural Resources Conservation Service (CA) – Code 383

It’s Prescribed Fire Season

In many wildland areas, smoke can often be seen throughout the winter. More than likely, this is not due to uncontrolled wildfire, but rather prescribed fires that are started when the weather is less conducive to catastrophic burns, allowing firefighters and crews to prepare for when wildfire season picks up again.  

 

30230_628921240365_2148150_n.jpgA Rx fire (controlled pile burning) I helped ignite in Golden Hills near Tehachapi, CA

Prescribed fire is one of the most effective mitigation concepts for reducing the outbreak and spread of wildfires. SmokeyBear.com defines prescribed fire as the controlled application of fire by a team of fire experts under specified weather conditions that help restore health to fire-adapted environments.  Prescribed fires can sometimes be confused with “backfiring” or “controlled burning” which typically refer to different types of prescribed and controlled fires. In many cases by safely reducing excessive amounts of brush, shrubs, and trees, prescribed burning can help reduce the catastrophic damage of wildfire on wildlands and surrounding communities.

In the Golden Hills photo above, the piling and burning of excess fuel was intended to make the fire road safer (this technique is sometimes called road brushing) and also to provide a fire break between Hwy 58 (a major thoroughfare) and the densely populated Golden Hills community.

Smoke Color Can Depict Fuel Type

Smoke is made up of particulates, aerosols and gases, and identifying the characteristics of each in a given smoke plume can be helpful when fighting fires. Reading smoke can tell a firefighter what is currently happening with a fire as well as what might happen in the future. One particularly important factor in predicting fire behavior is the color of the smoke emitted.

 

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Smoke is the biproduct of the fuels it is burning.  The color of the smoke indicates to firefighters the type and density of the fuels involved, all of which gives hints as to what the fire might do next.

White smoke can often mean material is off-gassing moisture and water vapor, meaning the fire is just starting to consume material. White smoke can also indicate light and flashy fuels such as grass or twigs.

Thick, black smoke indicates heavy fuels that are not being fully consumed. At times, black smoke can be an indicator that a manmade material is burning such as tires, vehicles or a structure. As a general rule, the darker the smoke, the more volatile the fire is.

Grey smoke can indicate that the fire is slowing down and running out of materials to burn.

2015 Wildfire Acreage Tops 10 Million for the First Time

2015 was a significant year for wildfires with the total acreage cresting 10 million for the first time on record. To put it in perspective, 10 million acres is roughly 7.5 million football fields, 12,000 Central Parks, or 15 Rhode Islands.

 

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Reported Wildfires from GeoMac and Fire Statistics from NIFC

2015 actually saw fewer fires than the 10-year average, but the total acres burned was more than 3.5 million greater than average. Alaska’s dozens of huge wildfires accounted for more than half of the total acres burned nationwide. Acreage-wise, an area the size of the entire state of Massachusetts burned inside of Alaska.

The Rocky Mountain and Southwest regions were quieter than normal. Major wildfire complexes raged for weeks in Idaho, NE Washington, Northern California, and Oregon. In terms of destruction, Northern California’s Butte and Valley wildfires combined to destroy 818 and 1958 structures respectively, the 7th and 3rd most in the state’s history.

WildFire 101: Haines Index

Haines Index is used to indicate the potential for rapid fire growth due to dry and unstable atmospheric conditions over a fire area. The index is a simple way to measure the atmosphere’s contribution to the fire’s growth potential. A high Haines Index is correlated with large fire growth where winds do not dominate fire behavior.

During days with a high Haines index and a Lightning Activity Level (LAL) above 4, fire behavior can become very erratic, unpredictable and difficult for resources to control and contain.

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2014 Incident Response Pocket Guide, Page 65

Wildfire 101: Lightning Activity Level (LAL)

The Lightning Activity Level (LAL) is a measurement of cloud-to-ground lightning activity observed (or forecasted to occur) within a 30 mile radius of an observation site.

 

 The LAL is part of the National Fire Danger Rating System (NFDRS) and consists of two reports. The first report covers the period from the previous day’s observation until midnight (referred to as Yesterday’s Lightning) and the second report covers the period from midnight until the present day’s observation time (referred to as Morning Lightning).  Each report is assigned a number on a scale of 1 to 6 which reflects the frequency and character of the lightning. The scale for 1 to 5 is exponential, based on powers of 2 (i.e., LAL 3 indicates twice the amount of lightning of LAL 2). LAL 6 is a special category for dry lightning (see description below) and is closely equivalent to LAL 3 in strike frequency.

 

The Lightning Activity Level on a scale of 1 to 6 as described below:

LAL 1: No thunderstorm or building cumulus clouds observed.

LAL 2: A single or few building cumulus clouds with only an occasional one reaching thunderstorm intensity observed. Thunderstorms or lightning need not be observed for this activity level to be assigned; however at least one large cumulus cloud must be present.

LAL 3: Occasional lightning (an average of 1 to 2 cloud-to-ground strikes per minute) is observed. Building cumulus clouds are common; thunderstorms are widely scattered.

LAL 4: Frequent lighting (an average of 2 to 3 cloud-to-ground strikes per minute) is observed. Thunderstorms are common and cover 10 to 30 percent of the sky. Lightning is primarily of the cloud-to-cloud type but cloud-to-ground lightning may be observed.

LAL 5: Frequent and intense lightning (cloud-to-ground strikes greater than 3 per minute) is observed. Thunderstorms are common, occasionally obscuring the sky. Moderate to heavy rain usually precedes and follow the lightning activity. Lightning of all kinds (cloud-to-cloud, in-cloud and cloud-to-ground) is characteristically persistent during the storm period.

LAL 6: A dry lightning situation. Low lightning flash rate observed (less than one to three cloud-to-ground strikes per 5-minute period per storm cell passage). Scattered towering clouds with a few thunderstorms; bases of the clouds are high. Virga is the predominate form of precipitation.

 

National Wildfire Coordinating Group

http://www.nwcg.gov/term/glossary/lightning-activity-level-(lal)

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. 

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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.

 

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

Wildfire 101: Fire Anatomy

Wildland firefighters use very specific terminology to describe the various parts of a fire.  The fastest-moving portion is designated the “head” of the fire, the sides of the fire are known as the “flanks”, and the slowest moving portion is known as the “tail” or “heel” of the fire. The origin of the fire is usually near the heel. A “finger” is a small area that is protruding from the main body of the fire, and may previously have been the head before a wind shift caused the fire to spread in a different direction.

Depending on the fuel and its arrangement, the head typically has the greatest flame length, flame depth, and rate of spread. This is also where the most active attack on the fire takes place.

The flanks of a fire burn outwards into the unburned vegetation. This results in the flanks having less alignment with the wind than the head, normally reducing their intensity and rate of spread. Flank fire intensity nearest the head is higher, particularly where the flanks meet the head which is known as the shoulder.

The rear portion of a fire is called the tail or heel, and is where there is the least amount of fire spread. Usually the flames at the tail are being bent towards the already-burnt fuel. The tail or heel is potentially the slowest moving part of a fire with the shortest flame length. Tail fires usually demonstrate low amounts of fire activity, but present a significant risk if they burn into areas that are more supportive of increasing fire behavior.

An “island” is a portion of unburned fuel that is inside the “black” (burned area) of an active fire. This often occurs when there are high moisture levels in that area,  or when the type of fuels or the topography of that area do not lend themselves to burning.  

“Spotting” occurs when the burning embers of fuel are carried upwards by wind and then distributed amongst the areas of unburnt fuel ahead of the main fire. The area immediately under the smoke plume is particularly vulnerable to spotting, although embers can be carried considerable distances and result in significant secondary fires. Spotting can break control lines or threaten the escape routes of ground personnel working the fire.

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Parts of a fire. Image courtesy of Becoming an Air Tanker Pilot.

 

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.