S190 Module 2 Test Answers

Question: Local topography effects a fire's, (blank), & (blank).

Answer: Intensity, and, Rate/Direction of Spread.

Question: A slopes, (BLANK), is the compass direction the slope faces.

Answer: Aspect

Question: The, (blank), of a slope determines the effect of the sun's heat on the slope's plants & trees, air temperature, & moisture retention of the soil.

Answer: Aspect

Question: Solar, (blank), heating can influence fire behavior by influencing fuel moisture and ignition points.

Answer: Radiant Heating

Question: A, (blank), facing slope tends to have heavier fuels, lower temperatures, higher humidity, & higher fuel moisture, than a, (blank), facing slope.

Answer: North, South

Question: In the Northern Hemisphere, the slopes facing, (blank), receive direct sun rays & become hotter than the slopes facing any other direction.

Answer: South

Question: In the absence of winds, fire usually moves, (blank), uphill than downhill.

Answer: Faster. So the steeper the slope, the faster a fire moves.

Question: Why is the rate of spread (ROS) increased for upslope fires?

Answer: Because:1. The flames are closer to fuel sources.2. Wind currents typically move uphill during the day, pushing heat to new fuel sources.3. Upslope fires create a draft, increasing the ROS.

Question: Wildland fires tend to burn much faster upslope than on level ground because of, (BLANK).

Answer: Preheated fuels

Question: When you have a fire at the top of a slope, building a, (blank), just beyond a ridge will help you contain the advancing fire.

Answer: Fireline

Question: Slope is measure in, (blank over blank), which is expressed as a percentage.

Answer: Rise over RunExample: A rise of 25 feet divided by a horizontal distance of 100 feet & then multiplied by 100 represents a 25 percent slope.

Question: Upslope fires can cause, (blank), to roll downhill.

Answer: Burning Debris

Question: What is a "chute"?

Answer: A chute is a steep v-shaped drainage on a slope which can easily channel smoke and fire upward at a rapid rate.

Question: What is a "saddle"?

Answer: A saddle is a common name for a depression between two adjacent hilltops.

Question: Why are "chutes" & "saddles" so dangerous?

Answer: 1. They drastically accelerate fires.2. They alter the flow of winds causing erratic fire behavior.3. They change the rate and direction of spread by acting like chimneys & literally propel the fire up as if through a stove pipe.

Question: Wind channeling is, (blank).

Answer: Is a direct result of natural features like chutes & saddles.

Question: What are the three different types of canyons?

Answer: 1. Box canyons2. Narrow canyons, &3. Wide canyons

Question: What is a Box Canyon's specific effect on fire?

Answer: The creation of strong upslope drafts results in extreme fire behavior.

Question: What is a Narrow Canyon's specific effect on fire?

Answer: Fire can easily spread fuels on the opposite side by radiation and spotting.

Question: What is a Wide Canyon's specific effect on fire?

Answer: Cross-canyon spotting of fires is not common except in high winds.

Question: Fires starting near the base of box canyons & narrow canyons may react similar to, (blank).

Answer: Similar to a fire in a wood burning stove or fireplace. Air will be drawn in from the canyon bottom creating very strong upslope drafts.These upslope drafts create what is called the "chimney effect".

Question: As air drops in elevation the atmospheric pressure, (blank).

Answer: Increases. This causes the air to compress and heat. The resulting winds can create poor conditions for wildland fire control.

Question: (Blank), winds are the result from air being forced over mountain ridges by convection or high barometric pressure.

Answer: Gravity Winds

Question: Because of high temperatures, fuels as, (blank), elevations, dry out earlier in the year than those at, (blank), elevations.

Answer: lower elevations, higher elevations

Question: There are typically less fuel loads at, (blank), elevations.

Answer: higher elevations

Question: What is a "barrier" defined as?

Answer: Any obstruction to the spread of fire, typically an area or strip lacking any flammable fuel.

Question: What are some natural barriers?

Answer: Rivers, lakes, burned areas, swamps, & rock outcroppings.

Question: What are some man-made barriers?

Answer: Roads, highways, reservoirs, & firelines constructed by fire resources.

Question: When fuels are separated by natural or man-made barriers, (blank), may not be sufficient to preheat or ignite the surrounding fuels.

Answer: Radiant heat

Question: What are two things that effect fuel types?

Answer: Elevation and moisture content

Question: What are examples of slash and blow-down fuels?

Answer: Dead fall, logging residuals.

Question: What are examples of timber fuels?

Answer: Oaks, hickory, cypress, & cedar.

Question: What are examples of shrub fuels?

Answer: Mesquite, chaparrel, & Alaska black spruce

Question: What are examples of grass fuels?

Answer: Wild oats, & tundra species.Note: Grasses burn the hottest and fastest of all the fuel types.

Question: What are some examples of man-made fuel sources?

Answer: Log decks at saw mills, dump sites, & above-ground oil and natural gas pipelines.

Question: What is one fuel that you might find no matter where you're fighting fires?

Answer: man-made structures

Question: What are 7 fuel characteristics that fire behavior is dependent on?

Answer: 1. Fuel Loads2. Size & shape3. Continuity4. Vertical arrangement5. Moisture6. Temperature, &7. Compaction.

Question: (Blank), refers to the amount of both live & dead fuel in a specific area.

Answer: Fuel load (sometimes called fuel volume)

Question: Fuel, (Blank), &, (Blank), affect the rate of heat transfer and the change in moisture content.

Answer: Fuel size & shape

Question: In general, (blank), fuels have a higher surface area to volume ratio then, (blank), fuels.

Answer: Fine fuels; Heavy fuels

Question: Fuel, (blank), is a characteristic used to describe the horizontal & vertical spacing of fuels is a given area.

Answer: Fuel continuity. Fuel continuity influences the spread of fire.

Question: Fuel, (blank), is the amount of water in a fuel, expressed as a percentage of the total oven-dry weight of that fuel.

Answer: Fuel moisture

Question: With all other factors affecting fire behavior being equal, areas of, (blank), fuel loading will generate more heat than those with, (blank), fuel loads.

Answer: Higher, Lesser

Question: Fuel size affects the rate of, (blank), and the change in, (blank), content.

Answer: Heat Transfer; & Moisture Content

Question: What are "light fuels"?

Answer: Light Fuels (also called fine or flashy fuels), are surface fuels, such as short grasses & light shrubs or brush which burn rapidly & with high intensity. Light fuels take on & give up moisture faster than heavier fuels. Generally, light fuels produce a relatively High ROS.

Question: What are medium fuels?

Answer: Examples of medium fuels include shrubs or brush up to 6 feet in height & the grass under-story. Medium fuels generally produce a Medium ROS.

Question: What are heavy fuels?

Answer: Heavy fuels consist of heavy continuous shrubs or brush more than 6 feet in height & timber slash. Combustion of these fuels includes high--intensity burning but generally a low ROS.

Question: What are uniform or continuous fuels?

Answer: They are fuels that are close together & spread evenly over an area.

Question: When fuels are close together, a fire spreads, (blank), because of radiant heat transfer and produces a relatively uniform and predictable ROS.

Answer: faster

Question: Fuel moisture is affected by the, (blank), & the, (blank), or percipitation

Answer: Amount & Duration

Question: The, (blank), the distance between aerial fuels, the slower they ignite.

Answer: further

Question: Fire in highly compact fuels generally burn with, (blank), intensity.

Answer: Low Intensity

Question: Subsurface fuels, (blank) burn rapidly.

Answer: Don't

Question: Once ignited, (blank), fuels are often difficult to find and extinguish.

Answer: Subsurface fuels

Question: (Blank), fuels burn rapidly once they ignite because air circulates easily between these fuels and the ground.

Answer: Arial fuels

Question: (Blank), fuels take on and lose moisture faster than, (blank), fuels.

Answer: Light; Heavy

Question: (Blank), or, (blank), plants, usually have a lower moisture content than young or live plants.

Answer: Old or dead

Question: Moisture in live fuels depends primarily on the moisture in the soil, whereas the moisture in dead fuels depends on, (blank), (blank), & (blank).

Answer: Atmospheric temperature, humidity, & solar radiation.

Question: What is "Equilibrium moisture content"?

Answer: It refers to the time it takes for the moisture in fuels to equalize with the moisture in the surrounding air.

Question: What do warm & hot winds do?

Answer: They usually accelerate the loss of moisture by lowering relative humidity and increasing evaporation.

Question: Most fuels must reach between, (blank), &, (blank) degrees, in order to ignite.

Answer: 400 to 700 degrees Fahrenheit

Question: Fires generally burn at, (blank), intensity and spreads slowly in highly compact fuels.

Answer: Low

Question: What are the three "fire environment components"?

Answer: Topography, fuel, & weather.

Question: (Blank), is the most variable of the three fire environment components.

Answer: Weather

Question: What are the 4 elements of Weather?

Answer: 1. Temperature2. RH3. Precipitation, &4. Wind

Question: (Blank), is variable due to the time of day, the weather, the seasons, latitude, elevation, topography, & the type of surface it's near.

Answer: Temperature

Question: (Blank), is the primary culprit for fuel, ground, & air temperature,

Answer: Solar radiation

Question: Moisture in the air is known as, (Blank).

Answer: Relative Humidity

Question: (Blank), affects the amount of moisture air can hold.

Answer: Air temperature.

Question: When air holds the maximum amount of moisture, the air is saturated, and its RH is, (Blank), percent.

Answer: 100 percent

Question: Relative Humidity can add or remove, (blank), to fuels.

Answer: Moisture

Question: More moisture in the air reduces the, (blank), point of fuels.

Answer: Ignition Point

Question: When the, (blank), is low (less than 30 percent), air absorbs moisture from fuels, dehydrates them, and makes them more susceptible to ignition.

Answer: Relative Humidity

Question: Generally, (blank), humidity increases fire activity, creates a greater fire intensity, higher rate of spread, & more spot fires.

Answer: Low humidity

Question: Temperature and Relative Humidity have a, (blank) relationship.

Answer: Inverse relationship.

Question: The majority of large fire outbreaks occur when air temperature is, (blank), and the RH is, (blank).

Answer: High; Low

Question: (Blank), kits include a sling psychrometer that measures local temperature & humidity.

Answer: Belt Weather Kits

Question: (Blank), air holds less moisture than hot air.

Answer: Cold Air

Question: Cool air can help you control wildfires by increasing the level of, (blank), in the fuels.

Answer: Moisture

Question: Local microclimates can, (blank), fire activity.

Answer: Alter

Question: What is "atmospheric stability"?

Answer: Atmospheric stability is the degree that vertical motion is the atmosphere is enhanced or suppressed.

Question: Stability is directly related to the, (blank), distribution of the atmosphere.

Answer: temperature distribution

Question: unstable air encourages the, (blank), movement of air and tends to increase fire activity.

Answer: vertical movement

Question: Atmospheric stability can be determined by measuring the rate of, (blank), change with differences in elevation.

Answer: Temperature change

Question: Air cools as it rises and expands and, (blank), as it descends and compresses.

Answer: Heats

Question: Steady winds or smoke rising up and spreading out in a horizontal fashion indicate, (blank), air.

Answer: Stable

Question: Smoke rises more in a column in, (blank), conditions.

Answer: Unstable

Question: What are the three types of clouds that you should be on the lookout for?

Answer: 1. Cumulus2. Cumulonimbus, &3. Stratus cloud sheets

Question: (Blank), clouds are generally easy to spot as they are slightly "fluffy" and have rounded tops with a flat base. These clouds have vertical air currents indicating unstable conditions with possibly gust or strong winds.

Answer: Cumulus Clouds

Question: The, (blank), of cumulus clouds indicate the depth and intensity of the instability.

Answer: Height

Question: (Blank), clouds, often called thunderheads often indicate strong, gust winds that shift erratically as a storm passes.

Answer: Cumulonimbus Clouds

Question: (Blank), clouds indicate stable layers in the atmosphere with little or no winds.

Answer: Stratus Clouds

Question: What is an "inversion layer"?

Answer: An inversion layer is when the temperature actually increases with height. In such situations, the air is said to be stable as along as the inversion is present.

Question: Under an inversion, fuel moisture content is usually, (blank), decreasing ROS & fire intensity.

Answer: Higher

Question: What are three indicators when an inversion breaks?

Answer: 1. Increase in temperature2. Decrease in RH; &3. Increase or shift in wind

Question: What are 3 types of inversion?

Answer: 1. Night inversions2. Subsidence inversions; &3. Marine inversions

Question: Inversions can often be spotted because you see a, (blank), of clouds or smoke hanging over a surface.

Answer: Layer

Question: Night inversions are not only affected by the cool air moving in during nighttime hours, but also by:

Answer: Topography, Temperature, & Humidity.

Question: Measurements of, (blank), &, (blank), can indicate the strength of a night inversion.

Answer: Temperature & Humidity

Question: In the absence of a visible smoke or cloud layer, the top of the inversion can be found by measuring, (blank), at various points up and down the slope.

Answer: Temperatures

Question: What is a "thermal belt"?

Answer: A thermal belt is the top of an inversion layer. This area has the warmest air temperature and also has the lowest nighttime relative humidity & moisture content.

Question: (Blank), the thermal belt, fires are in cool, humid, & stable air, often with downslope winds.

Answer: BELOW

Question: What are "subsidence inversions"?

Answer: Subsidence is the large-scale sinking of air associated with high-pressure systems and usually contributes in the development of foehn winds.

Question: Burning conditions can become severe during, (blank), inversions because skies are typically clear or cloudless and extended periods of above-average temps & below-average RH can dry out fuels.

Answer: Subsidence Inversions

Question: (Blank), inversions are common in the summer and may be caused when winds reverse at night and become a land breeze.

Answer: Marine Inversions

Question: Inversions on the, (blank) coast are called marine inversions.

Answer: West Coast

Question: Air is extremely, (blank), in an inversion layer.

Answer: Stable

Question: (Blank), decreases both above and below in an inversion layer.

Answer: Temperatures

Question: What are 4 indicators of an unstable atmosphere?

Answer: 1. Clouds grow vertically and smoke rises to great heights.2. Cumulus clouds a represent3. There is good visibility; &4. Gusty winds and dust devils or fire-whirls

Question: Define "wind"?

Answer: Wind is basically air in motion and is measured in terms of: direction, speed, & turbulence.

Question: What are the two most important weather-related elements affecting wildland fire behavior?

Answer: Wind & Fuel Moisture. Wind is the least predictable.

Question: (Blank), behavior largely determines the rate and direction of spread for a wildland fire.

Answer: Wind

Question: Wind has both, (blank), &, (blank), effects

Answer: Direct & Indirect Effects

Question: What are the three essential types of winds?

Answer: 1. General Winds2. Local Winds; &3. Convective Winds

Question: What are the two types of general winds that are associated with high & low pressure systems?

Answer: 1.Frontal Winds; &2. Foehn or Gravity Winds

Question: The leading edges of two air masses are called, (blank), and they create frontal winds.

Answer: Fronts

Question: When cold air masses replace warm air masses, the leading edge of the cold mass is called the, (blank.

Answer: Fronts

Question: When a cold front advances on a, (blank), front, it produces strong and gusty winds that change quickly.

Answer: Warm Front

Question: (Blank), winds result from air being forced over mountain ridges by convection or high barometric pressure. The air then cascades down-slope as gravity winds. As the air drops in elevation, the atmospheric pressure increases, which causes the air to compress and heat.

Answer: Foehn Winds

Question: (Blank), winds are described as strong, hot, and dry.

Answer: Foehn Winds

Question: (Blank), winds are a by-product of the daily heating and cooling of the earth's surface referred to as the diurnal cycle.

Answer: Local Winds

Question: How does hilly terrain cause various changes in local winds?

Answer: As the terrain such as a mountain or will rises, the heat will create an up-slope local wind. The air at this point will increase in temperature. As the air moves up and over the mountain and comes down the other side, a downslope, local wind is created by the cooler air. As the wind moves into flat terrain, the heat mixing with the cooler air coming from the downslope wind can create dust devils, whirlwinds, or other unpredictable behavior.

Question: What are "convective winds"?

Answer: Convective winds are essentially general winds that are affected by the localized heating of air that expands and rises wile cooler, denser air comes in to replace it.

Question: What are some examples of convective winds?

Answer: 1. Slope & valley winds2. Land & sea breezes3. Thunderstorm winds4. Whirlwinds; &5. Firewhirls

Question: Typically, the local wind pattern moves, (blank), during the day and, (blank), during the night.

Answer: Upslope; Downslope

Question: How are upslope winds produced?

Answer: Upslope winds are produced when the air in the valleys rises as it becomes warmer than the air along the mountain tops.

Question: (Blank) facing slopes receive solar energy at sunrise, so the downslope-to-upslope change takes place first on, (blank) aspects.

Answer: EAST

Question: How are downslope winds produced?

Answer: Downslope & down valley winds are produced when the air along the mountain tops sinks as it becomes cooler than the air in the valleys.

Question: When the sun fades in the afternoon and the air cools, valley winds switch directions and begin a; (blank), slope movement.

Answer: Downslope

Question: The change from downslope to upslope can rapidly change, (blank), behavior from inactive in a matter of minutes.

Answer: Wildland Fire

Question: V-shaped crevices, saddles, & narrow canyons, are sometimes referred to as, (blank).

Answer: Chimneys

Question: (Blank), can create unstable updrafts in response to localized heating.

Answer: Chimneys

Question: Upslope winds become valley winds when they reach, (blank), mph

Answer: 7 mph

Question: Thunderstoorms are a good indicator of an, (blank), air mass and generally arise as a result of extreme differences in localized heating of the air near the ground.

Answer: Unstable air mass

Question: The winds that thunderstorms produce are very strong, often unpredictable convective winds and can produce, (blank), or. (blank).

Answer: Whirlwinds and Firewhirls

Question: (Blank), wind, flows up during the day and down during the night.

Answer: Slope Wind

Question: Land sea breeze flows from the ocean toward the, (blank).

Answer: Inland

Question: Thunderstorm winds are created by, (blank), clouds and can be gusty and erratic.

Answer: Cumulus

Question: (Blank), tend to develop in blackened, dry, burned, & flat terrain.

Answer: Whirlwinds

Question: What are firewhirls?

Answer: Firewhirls are spinning columns of rising air carrying gases, fumes, and debris.

Question: What are 5 types of critical fire weather conditions?

Answer: 1. Strong & shifting wind2. Very low RH3. High Temperature4. Unstable atmosphere; &5. Dry lightning

Question: Large clouds of dust often precede the arrival of a, (blank).

Answer: Cold Front

Question: Wind velocity, (blank), before a cold front arrives.

Answer: Increases

Question: A cold front can have low or high, (blank), depending on its origin or locaiton

Answer: Relative Humidity

Question: (Blank),clouds are often the harbinger of lightning, rain, & hail.

Answer: Cumulonimbus Clouds

Question: What are some visual indicators of lightning and thunderstorms?

Answer: 1. Tall, building cumulus clouds2. A cauliflower-shape to the top of clouds3. Clouds with dark, flat bases; &4. Anvil-shaped clouds with a fuzzy appearance

Question: The anvil-shaped cloud points in the, (blank), the wind is blowing. Expect your fire to react to that wind movement.

Answer: Direction

Question: What results would you expect on the Approach, Over a fire, & Departure during a storm.

Answer: 1. Approach: Expect winds to blow from the storm toward the fire.2. Over a fire: Expect highly erratic winds that can change direction unpredictably3. Departure: Expect winds to shift so they=re blowing back to the fire.

Question: As a storm moves over a fire, the wind can spread, (blank), in all directions

Answer: Horizontally

Question: As a storm moves out of the fire area, the wind blows from the storm, (blank), the fire.

Answer: Toward

Question: Wildland fire activity is usually at its lowest between (blank), and, (blank), AM.

Answer: 4:00 am and 6:00 am

Question: Fire activity can, (blank), between 6:00 am and 10:00 am

Answer: Increase

Question: (Blank), is a, favorable time to gain control of a wildfire.

Answer: Nighttime

Question: Why do night inversions form?

Answer: Night inversions form because a layer of air near the earth's surface cools more quickly than air at higher altitude.

Question: What are 3 types of general winds

Answer: 1. Gradient winds2. Frontal winds; &3. Gravity winds

Question: Identify 4 factors that interact to create weather conditions?

Answer: 1. Relative humidity2. Temperature3. Precipitation; &4. Wind

Question: Identify 2 of the primary weather services you will see in wildland firefighting?

Answer: 1. National Weather Service (NWS)2. Predictive Services