National Fire Danger Rating System

Proposed UpdateSept. 17, 2014

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Proposed Changes to NFDRS• Has remained mostly static for

almost 40 years.• Update current components of

NFDRS: Live Fuel Moisture Model Dead Fuel Moisture Model

• Consolidate existing fuel models to 4 fuel response types based on existing Fire Behavior Fuel Models: Grass Brush Timber Slash

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Case for Change

• NFDRS is too complex

– Much of the complexity adds little insight

• Fire Danger expertise is diminishing

• Practitioners demand it:

• WIMS operations simplified

• Updated system will provide clearer and more intuitive output

• Extension of logic that has been taught for years

• Most fatality investigations cite a lack of knowledge of local fire

danger as contributing factor.

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Case for Change (cont’d)• Prepares NFDRS to integrate into future uses of

weather data• Described in the FENC/CEFA RAWS Network Analysis of 2011,

including increasing use of gridded data in analysis products like NFDRS

• Preparing to do this for over a decade:• Installing solar radiation sensors on RAWS• Evaluating new model performance• Lessons learned in extensive analysis in Fire Danger

Operating Plans correlating NFDRS Indices, fuel models and fire activity.

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New Live Fuel Moisture ModelGrowing Season Index - GSI

Current live fuel moisture model acknowledged as the weakest model in NFDRS.

• GSI is a meteorological based phenology model

• A significantly better model using elements from a standard once-daily fire weather observation

• Requires no constant human intervention yet accurately reflects within season and season to season live fuel conditions

• Is currently running in the WIMS Test System

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Average GSI and Measured Nevada Sagebrush Moisture1986-2014

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New Fine Dead Fuel Moisture ModelNelson

• Current model developed by Fosberg in the 1970’s. – Uses once-daily weather information and requires manual entry

of ‘state-of-the-weather’ and ‘fuels wet’ codes– Calibrated for mid-afternoon conditions

• Nelson Model:– More accurately models diurnal fine dead fuel moisture using

elements from hourly fire weather observations– Requires no daily human intervention– Has been running in a prototype mode in operational WIMS

since December, 2011– While not part of the Nelson model, in the same update, the

“automated state of weather” was implemented based on solar radiation at the 1300 observation and measured precipitation over the past 24 hours.

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Consolidate Fuel Models• John Deeming, the lead developer of the NFDRS in

use today, proposed reducing the 9 fuel models in the 1972 system to 4 in the 1978 update – He negotiated to 20 with his steering committee – In the 1988 update, essentially 20 more were added

• Outputs from most NFDRS fuel models are not unique Similarity analysis of output distributions revealed just four

really unique fuel model types.

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ERC correlation analysis between four model pairs

Mor

e si

mila

r

L

ess

sim

ilar

Only Grass Not Only Grass

Mostly Grass and Brush More than Grass and Brush

Minimal live More live

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L A N T F B D S O K J I G C E R H Q U P0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Percent of Active NFDRS Stations in WIMS (n=2040) with Each Fuel Model, Grouped by Type

ShrubGrass Slash Timber/Litter

NFDRS Stations can track from 1 to 4 fuel models

Every NFDRS Station has a G Model

Only 9 fuel models are being used by 10% or more of the 2040 NFDRS Stations

2 Grass Models (L / A)3 Shrub Models (T / F / B)4 Timber Models (G / C/ E / R)

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Implications and Ripple Effects• Possible pushback from the field to reducing fuel

models (“my fire danger area is unique”)

• Impacts on training – S-491, Intermediate Fire Danger Rating redesign

• Working with the Wildland Fire Information and Technology (WFIT) to mitigate and resolve any potential impacts to systems• WIMS, WFDSS, FSIM, etc…

• Gains in simplicity widens the breadth of people in the field that can understand and use fire danger.

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Workload Impact• Some temporary increases in workload:

– Fire personnel will be required to complete new analyses to provided updated system breakpoints - because old percentiles and breakpoints will be obsolete.

– However, this re-analysis would have been required by the field with just the transition to the Nelson (dead fuel moisture) model,

– Additionally, it is recommended that breakpoints be re-visited yearly as part of the annual preparedness review process.

• Automation of many operations and daily inputs to the model will decrease work load for dispatchers and managers on a day to day basis.

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What Happens if You Say “No”?• You’ll miss:

– Advantage of the latest technology for decision making.– Opportunity to simplify the system which would make it more user

friendly.

• Harder to integrate new products coming online – Such as the 7 day NFDRS forecast.

• Implementation of a new, up to date, easy to use NFDRS moves us back to one true national system.– Currently several different systems depicting fire danger on a daily

basis, • 78 and 88 version of NFDRS• Canadian FDRS• Predictive services 7 day fire potential.

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Timeframes

2014• September

• Approval from NWCG to proceed with changes.

• December• Technical documentation for new system available in draft form.

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Timeframes2015

• January• Develop NFDRS 2016 and move to Weather Information Management System

(WIMS) testing side.• Many of the changes are already in WIMS and FireFamily+, but have simply not been

tied together yet.

• March• Stand down S-491 classes while developing new classroom version.

• July • Develop webinar/self-paced training for prior S-491 students to become

familiar with the new system.• FireFamily+ updated to include the NFDRS 2016 version.

• October• S491 classes resume with emphasis on NFDRS 2016 system.

• November• Fire Behavior Subcommittee to review basic Fire behavior class modules

focused on NFDRS. Modules will include updated information on live and dead fuel moisture

calculations as well as Fire Behavior models utilized in the 2016 NFDRS. PocketCard lessons

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Timeframes

2016• January

• NFDRS 2016 moved from test side of WIMS to production side of WIMS. (Fully Operational)

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Decision

Approval and support for the updates to NFDRS.

• If approved: FENC will draft a letter for NWCG to review. This letter

will go out under NWCG letter head to the field which outlines changes to be made to the system.

FENC will draft a communication for NWCG to coordinate with the federal Fire Management Board for integration with WFIT and implementation.

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Questions?

Thoughts?