Wildfire 101: Dead Fuel Moisture

What is Dead Fuel Moisture?

A recent lack of significant rainfall has kept Southern California in extreme drought, which means there is increased potential for significant wildfire due to dangerous levels of dead fuel moisture. As explained by NOAA, fuel moisture is a measure of the amount of water in a potential fuel, and is expressed as a percentage of the dry weight of that fuel.  So if leaves and downed trees were completely dry in a given area, the fuel moisture level would be 0%.

When fuel moisture content is high, fires do not ignite readily, or at all, because most of the fire’s heat energy is used up trying to evaporate and drive water from the plant in order for it to burn. When the fuel moisture content is low (like in drought-stricken Southern California), fires start more easily and can spread rapidly as all of the heat energy goes directly into the burning flame itself. When drought is extreme and the fuel moisture content is less than 30%, that fuel is considered to be dead, giving us the “dead fuel moisture” designation.

The United States Forest Service which manages a nationwide fuel moisture index, classifies fuel moisture based on two metrics:  fuel size and time lag.

  • Fuel size refers to the actual physical dimensions of the fuel (i.e. the diameter of downed logs or branches).
  • A fuel’s time lag classification is proportional to its diameter and is loosely defined as the time it would take for 2/3 of the dead fuel to respond to atmospheric moisture.  For example, if a fuel had a “1-hour” time lag, one could expect its wildfire susceptibility to change after only 1 hour of humid weather.  Fuels with 100- or 1000-hour time lags would be expected to be much less resistant to humidity.

Fuel moisture is dependent upon both environmental conditions (such as weather, local topography, and length of day) and vegetation characteristics.  The smallest fuels most often take the least time to respond to atmospheric moisture, whereas larger fuels lose or gain moisture slowly over time.

The classifications of the Forest Services’s index (also known as NFDRS) are as follows:

Dead Fuel Moisture

The Dead Fuel Moisture Time Lag Classes as defined by the United States Forest Service

Drought Conditions Improving in California

According to the weather almanac, San Diego–home to RedZone’s intelligence team–had received a minuscule .7 inches of rain since June 1st.  Luckily, a significant rain event entered the southern California region on Thursday evening, adding wetness to the low fuel moisture readings around the region.

Since late Thursday night (12/15), significant rains have finally fallen across the area. The gusty winds and showers are expected to begin tapering off late Friday as the moisture exits to the east, but a long-awaited significant wetting event has been left behind. Early reports on Friday (12/16) have measured up to 3.3 inches in the East County Mountains and greater than 1 inch along the San Diego Coast, far exceeding the cumulative totals since June.

As we discussed a few weeks ago, the drought situation in Northern California had already improved earlier this year, and now the dry weather in Southern California appears to be coming to an end.


Source(s):

http://patch.com/california/ranchobernardo-4sranch/storm-moves-through-san-diego-region

https://www.ncdc.noaa.gov/monitoring-references/dyk/deadfuelmoisture

http://www.nwcg.gov/glossary/a-z

http://www.wfas.net/index.php/dead-fuel-moisture-moisture–drought-38

Landslide Concerns in Fire-Ravaged Gatlinburg TN

While the community of Gatlinburg, Tennessee grieves their losses and starts planning how to recover and rebuild, a new threat confronts the area. An inch and a half of winter rain helped put out the horrific fire over the weekend, but as we’ve covered in the past, wildfire-scorched areas often have an increased risk of landslides and mudslides. Local fire crews have thus far reported several small landslides that are slowing their ability to access damaged areas.

wildfire landslides

Before and After Image of a Burn Scar from the Chimney Tops 2 Fire

How a Fire Can Increase Landslide Risk?

Depending on soil type and topography, vegetation and land cover have a significant impact on the stability of the soil. Under normal conditions, leaf litter and other surface vegetation slow the rainfall water moving down a given slope.  This allows much of that moisture to permeate through the soil and drain into the water table or aquifer below, leaving the surface soil relatively stable.  Even during heavy rainfall when surface soil becomes saturated, root systems from brush and trees help to keep the soil from moving downhill.

However, when vegetation is lost due to wildfire (or other reasons such as construction), the factors that keep soil in place are minimized, and there is greater risk that the soil’s surface tension in a given area is overcome by gravity and washes down the slope.

Gatlinburg is in the Great Smoky Mountains, a very old mountain range within the Appalachian Mountain region. Due to the age of the mountains and the region’s climate, the mountains themselves are very weathered, and have much deeper soils than the mountains in the Western United States. The region is also heavily wooded, so the roots of the dense vegetation help to stabilize the nearby soil. When the wildfires recently moved through the area, the vegetation and leaf litter was burned out, and the stabilizing root systems were compromised. Storms then came and assisted in firefighting efforts, but the lack of vegetation due to the recent burns caused a few small slides. Before winter brings snow to the normally wet area, an increased likelihood for flooding, mudslides, and landslides remains a worrying possibility. As of December 7th, there is little rain forecasted in the region for several days.

Visit ready.gov to learn about how to better protect yourself, your family, and your property from landslides and other hazards.

Wildfire 101: Modern Warning Systems

In the United States, effective systems are in place to help us plan for, respond to, evacuate from, and cope with dangerous and difficult emergency events.  Traditionally in the late twentieth century, mass media (television and radio) were relied upon to inform the general public of impending or ongoing dangerous situations. Previously, older technology like sirens were utilized for warning of impending situations, especially severe weather. While all are still prevalent today, much of the public were left uniformed if not within nearby proximity to one of these alert platforms. Today we have many more options at our disposal.

Modern Warning Systems

In June 2006, following criticism over the government’s response to Hurricane Katrina, President George W. Bush signed Executive Order 13407, ordering the Secretary of Homeland Security to establish a new program to integrate and modernize the nation’s existing population warning systems. Installment began on a nationwide system now known as the Integrated Public Alert and Warning System, or IPAWS.  IPAWS is an alert and warning infrastructure that allows Federal, State, and local authorities to alert and warn the public about serious emergencies using the Emergency Alert System (EAS), Wireless Emergency Alerts (WEA), and other public alerting systems from a single interface.

EAS is used to send emergency messages through cable, broadcast, and satellite television, as well as landline phone recordings. WEA refers to messages, similar to text messages, which appear as a notification to your mobile phone. They are sent by an authorized government authority through your mobile provider. Registration is not required for the national alerts through IPAWS, but a compatible phone and provider are required. The message contains information such as the type of alert, the time of the alert, the issuing agency, and any steps the recipient should take. The types of alerts include AMBER alerts for child abductions, extreme weather alerts, Presidential alerts during a national emergency, or other threatening emergencies in your area. Who receives the alerts is based on connectivity to the affected area’s cellular towers, so the alert is determined by the current location of the cellular device and not the address of the wireless phone owner. Of course, the benefit of this is if you are away from home and an emergency occurs in the area you are visiting, you will still receive the alert through the local cellular tower.

Reverse 911 is widely used for local emergency situations to be broadcast to email, home, and mobile phones

Reverse 911 is widely used for local emergency situations to be broadcast to email, home, and mobile phones

Other Alert Systems

Many local government agencies have additional alert services that offer greater detail to local emergencies through recorded messages, text alerts, or emails. In order to take full advantage, make sure to check local emergency services options (such as Reverse 911). Often, a registration process is required before you will receive the alerts. Similarly, other modern alert systems allow for notifications of other local emergency situations that also could prompt action.  A few examples:

  • PulsePoint is a mobile application which connects the local dispatch system with CPR-trained bystanders (and the location of the closest AED) regarding a nearby cardiac emergency event… effectively enabling “citizen superheroes.”
  • Google’s ‘Waze’ mobile app is a social-mapping-based means of reporting real-time accidents and traffic alerts.
  • The Incident Paging Network has also proven to be a useful tool for being alerted regionally within the network for a wide range of event types.
  • Here at RedZone we especially appreciate the advent of public alert and advance warning regarding an impending or ongoing disaster. Our RZAlerts are built on the success of this premise.

Sources:

https://en.wikipedia.org/wiki/Integrated_Public_Alert_and_Warning_System

fema.gov/integrated-public-alert-warning-system

Tree Death Fuels California Wildfires

Tree Death Adds Fuel to the Fire

A record 66 million trees have died in California since 2010, adding a huge fuel threat to an already dangerous fire landscape.  Not only are decomposing trees more flammable, they can also present a safety hazard to firefighters. Specifically, dead trees can fall during fires (which have resulted in deaths), and fallen trees can be an obstacle preventing vehicles and firefighters from reaching the fire.

Dead Wood Danger

When a tree dies, its wood dries out and becomes very flammable.  When building a campfire, there’s a reason we use downed wood instead of chopping down live trees. Healthy, living trees have a relatively high moisture content.  This helps trees survive a wildfire and slows the progress of that wildfire. When tree death occurs from old age or other reasons, standing dead or fallen trees provide a large amount of dry fuel for wildfires, encouraging fire growth and hindering efforts to put it out.

Bark Beetle impact from 2012 US Forest Service report

Bark Beetle impact from 2012 US Forest Service report

What’s Happening to the Trees?

Established trees are fairly resilient to seasonal changes in their environment, so it is difficult to understand exactly what is causing so much tree death in California. Perhaps not surprisingly, several stressors have been acting on the trees at the same time.

 

Drought:

California has been in an historic drought for the past five years. Most native California trees are fairly resilient to drought, but a prolonged drought weakens the trees and exposes them to pests and disease that a healthier tree could normally fight off.

Tree death (brown trees) near Julian in San Diego County

Tree death (brown trees) near Julian in San Diego County

Pests:

Tree bark is the main defense for trees against pests, disease, and fires. Bark beetles burrow into the bark and expose the trees to other pests or diseases, and can reduce their fire resiliency. Different types of bark beetles act as pests to different types of trees. The Pines and Conifers in the Sierra Nevada Mountains have been decimated by these beetles. Beetle-kill trees have been blamed for prolonging the firefight on the Beaver Creek Fire in Northern Colorado and also the Cedar Fire in California’s Southern Sierra Nevada Range. Tree deaths due to these beetles have been attributed to several major campaign fires across the west over the past few summers. The map above shows hard-hit beetle kill timber forests across the west (in red), which includes both the Cedar and Beaver Creek fire areas.

Disease:

The coast live oak trees have been exposed to Sudden Oak Death, which is caused by a non-native tree fungus. This fungus and other non-native diseases are responsible for an estimated 5 – 10 million oak tree deaths. Many dead trees were identified in the areas where the Soberanes fire near Big Sur is currently burning and have likely contributed (along with major drought) to its acreage eclipsing 100,000 this week.

Plans for Tree Death Prevention

Drought, pests, and disease all put stress on otherwise healthy trees.  When these stresses are combined, we can expect to see continued tree death at unprecedented scales. California has programs to both reduce the amount of tree death and to remove dead trees as a means of reducing fire danger.  Lately, resources have been too scarce to keep up with the levels of tree deaths plaguing the state. Learn more about the epidemic and what is being done to prevent further problems here.


Sources:

www.fs.fed.us

www.fire.ca.gov

Wildland Fire Engine Types

A wildland fire engine is specifically designed to assist in fighting wildfires by transporting firefighters to the scene and providing them with access to the fire, along with water and/or other equipment. Most parks are located away from urban areas and maintain their own wildland fire protection and suppression equipment, including wildland fire engines. There are multiple types of wildfire apparatus which are used by the United States Forest Service depending on the scenario at hand. They come in different sizes (Types) depending upon how many gallons of water they hold and the gallons per minute (GPM) the pump can produce. Most wildland fire engines are four-wheel-drive and have off road capability and can thus climb hills and make it through rough terrain.

2354445_orig.jpgProduction Bulldog 4X4 Extreme Brush Truck
Image courtesy http://www.4x4firetruck.com

Depending on where the engine is positioned in relation to a fire, it may carry as much as twice the national standard in fire hose. In areas where there is rugged terrain that keeps engines from driving directly to the fire, large hose lays are installed to transport water to the fire area. In desert areas with moderate terrain, less hose is used as it is easier to access the fire. Often the technique of pump-and-roll is used where the vehicle drives with the pump engaged while a firefighter uses a hose to spray water on the fire. This pump-and-roll feature allows the engines to make “running attacks” on vegetation fires, a tactic that can help minimize the rate of spread by having a firefighter walk the edge of a fire with a hose line and the engine trailing close behind. One advantage of engine crews is the ability to build “wet line”. A wet line is a fireline that uses water or foam in place of digging to mineral soil. This minimizes the impact to vegetation and limits erosion.

In the fall of 2007, the National Wildfire Coordinating Group agreed on a set of standards for all fire engines that are used for wildland firefighting. As structure engines are sometimes used on wildland fires, though primarily for structure protection, they are also included in the NWCG engine typing. Per the standards there are 7 types of fire engines.

 

engine_types.jpg

Wildfire 101: Incident Command System (ICS)

When working a wildfire incident, knowing who you report to and who is expected to report to you is imperative to maintain effective and efficient incident management. A system has been developed and honed by wildland firefighters over the years into what is known as the Incident Command System (ICS).

ICS is typically broken out into five major functional areas:

  • Command – Controls overall incident management
  • Operations – “Boots on the ground”, accomplishes objectives
  • Planning – Manages planning process
  • Logistics – Provides incident support, ensures Operations has what they need to do their job
  • Finance/Admin – Manages funds for the incident

The Incident Command System was developed by CAL FIRE following a series of catastrophic wildfires in the 1970s. The studies of these events concluded response problems related to communication and management issues, rather than a lack of resources or skills and knowledge. Now, ICS has been implemented in Emergency Operations Centers across the country, as well as in other fields such as healthcare and business.

The structure of ICS is easily adaptable to many types of incidents. As an example, the Federal Emergency Management Agency (FEMA) relies on ICS when responding to disasters. As an incident develops, more units and divisions are added based upon functional or geographic need. The adaptability and flexibility of ICS allows for efficient expansion and seamless transition throughout the duration of an incident.

ICS_Structure.png

 (Source: Federal Emergency Management Agency – ICS Resource Center)

Although these Sections (known as General Staff) are lateral and report up to the Incident Commander, they rely on each other to achieve the common goal and support each other. Operations needs Logistics to provide resources (people, machinery/vehicles, food/water) to achieve the incident objectives that the Planning team documents and tracks to make sure everyone is working toward a common goal.  Meanwhile, Finance/Admin keeps the incident within allowable budgets and ensures proper time tracking. All of this is overseen by and reported to the Incident Commander.

Depending on the incident, some timelines are longer and more developed than others. A small wildfire may be put out within a couple hours whereas others may last days, weeks, or months (such as the Chelan, WA fires of 2015). Throughout the incident, roles can easily be added or closed down as needed due to the flexible nature of the Incident Command System.

For further information on ICS and available training courses, please visit: FEMA’s ICS Resource Center.

 

Wildfire 101: The Fire Triangle and The Fire Tetrahedron

There are three components needed to start a fire: fuel, oxygen, and heat. This is commonly referred to as the fire triangle. If any one of the components is missing, a fire cannot occur.


fire_triangle.jpg

 Artist’s rendition of the Fire Triangle – Source: USFWS Alaska

The Fire Triangle is a simple way of understanding the three elements a fire needs to ignite: each side of the triangle represents one of the three ingredients – oxygen, heat, and fuel – demonstrating the interdependence of these ingredients in creating and sustaining fire. A fire naturally occurs when the elements are present and combined in the right mixture, meaning that fire is actually an event rather than a thing. When there is not enough heat generated to sustain the process, when the fuel is exhausted, removed, or isolated, or when the oxygen supply is limited, then a side of the triangle is broken and the fire will die.

Heat – A heat source is responsible for the initial ignition of fire, and heat is also needed to maintain the fire and permit it to spread. Heat allows fire to spread by removing the moisture from nearby fuel, warming surrounding air, and preheating the fuel in its path, enabling it to travel with greater ease. Heat can be removed by the application of a substance which reduces the amount of heat available to the fire reaction. This is often water, which requires heat for phase change from water to steam.

Fuel – Fuel is any kind of combustible material, and is characterized by its moisture content (i.e. how wet the fuel is), size and shape, quantity, and the arrangement in which it is spread over the landscape. The moisture content determines how easily that fuel will burn. Fuel can be removed naturally, as when the fire has consumed all the burnable fuel, or manually, by mechanically or chemically removing the fuel from the area.

Oxygen – The oxidizer is the third component of the chemical reaction.  In most cases, is simply comprised of the ambient air, and in particular one of its components, oxygen. Air contains about 21% oxygen, and most fires require at least 16% oxygen content to burn. By depriving a fire of air, it can be extinguished.

2000px-Fire_tetrahedron.pngThe Fire Tetrahedron (wikipedia)

In recent years, fire experts have redefined the triangle to a tetrahedron, adding an actual chemical chain reaction component to the three already present in the fire triangle. Basically, while the three classic components are still needed, an actual chemical reaction must take place in order for the fire to ignite.  Once a fire has started, the resulting exothermic chain reaction sustains the fire and allows it to continue until at least one of the elements of the fire is blocked. As with the fire triangle, as soon as one of the four elements of the tetrahedron is removed, combustion stops and the fire is extinguished.

Source: www.smokeybear.com

Fire Danger Signs: What Do They Really Mean?

Ever been driving along a highway, spotted a Fire Danger Sign, and wondered what it is truly indicating?

Fire Danger is a description of the combination of both constant and variable factors that affect the initiation, spread, and difficulty to control a wildfire in a given area. There are many systems and schemes that attempt to provide accurate and reliable predictions of fire danger, that analyze the fuel, topography, and weather, and integrate their effects into a set of numbers that fire managers can use to determine a rating.

todays-fire-danger-park-sign.jpg

Since 1974, five rating levels have been used to describe danger levels in public information releases and fire prevention signing:

Low (Green) – Fire starts are unlikely. Weather and fuel conditions will lead to slow fire spread, low intensity and relatively easy control with light mop-up. Controlled burns can usually be executed with reasonable safety.

Moderate (Blue) – Some wildfires may be expected. Expect moderate flame length and rate of spread. Control is usually not difficult and light to moderate mop-up can be expected. Although controlled burning can be done without creating a hazard, routine caution should be taken.

High (Yellow) – Wildfires are likely. Fires in heavy, continuous fuel such as mature grassland, weed fields and forest litter, will be difficult to control under windy conditions. Control through direct attack may be difficult but possible and mop-up will be required. Outdoor burning should be restricted to early morning and late evening hours.

Very High (Orange) – Fires start easily from all causes and may spread faster than suppression resources can travel. Flame lengths will be long with high intensity, making control very difficult. Both suppression and mop-up will require an extended and very thorough effort. Outdoor burning is not recommended.

Extreme (Red) – Fires will start and spread rapidly. Every fire start has the potential to become large. Expect extreme, erratic fire behavior. NO OUTDOOR BURNING SHOULD TAKE PLACE IN AREAS WITH EXTREME FIRE DANGER.

– See more at: http://www.nps.gov/fire/wildland-fire/learning-center/fire-in-depth/understanding-fire-danger.cfm#sthash.qf9PGgN8.dpuf

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.