Chapter 3 Flashcards
DMC - Moisture Code
Tracks moisture in top organic layer, 5-10 cm. Inputs are temp, RH, and rain. Indicator of receptivity of lightening ignition.
FFMC - Moisture Code
Tracks moisture content of surface litter. Inputs are temp, RH, wind and rain. Indicator of ease of ignition. Min 75 for ignition and spread.
DC - Moisture Code
Tracks moisture >10 cm deep. Inputs are temp and rain. Indicator of seasonal drought effects on fuels and amount
of smoldering in deep duff layers and large logs.
ISI - Behavior index
Combines FFMC and wind speed to create a unitless index of potential ROS. ISI > 10 = significant potential for spread.
BUI - Behavior index
Combines DMC and DC to create a unitless index of the total amount of fuel available for combustion/consumption. BUI > 80 represents a very significant level.
Empirical Models
Empirical models are based on relationships between variables documented with real-world observations.
What are three different applications of FWI System values?
Prevention - Public fire advisories
Response - Preparedness, detection, suppression, mgmt
Recovery
The general model of moisture exchange used to calculate the FWI System fuel moisture codes
Moisture exchange is tracked in and out of three forest floor layers from day to day
1) Time lag associated with each fuel moisture code 2) the weather inputs that effect the time lag for each fuel moisture code 3) Why the time lags differ for each fuel moisture code
FFMC: 2/3 days, varies with temp RH, and wind speed
DMC: 15 days, varies with temp and RH
DC: 53 days, varies with temp
Three different methods that could be used to calculate FWI System components
There are three reports that can be used to calculate FWI. FTR-35 listed above. FTR-33 which excel. FTR-25 which uses a set of tables. Lastly, various software tools such as an R-pkg or RedApp.
