Wednesday - U.S. Drought Monitor Forum

1. Fire Seasonal Outlook: Western U.S.
Nick Nauslar
Ph. D. Candidate
Desert Research Institute
Program for Climate, Ecosystem, and Fire Applications

2. Outline
• Seasonal fire outlook
– Fire potential
– What goes into it?
• Preview of the West’s fire season
– Where will it be busy?
– Official outlooks and my take

3. Fire Potential
• Conditions adequate to support fire ignition
and spread
• Dry fuels necessary, BUT need fuels to burn…
• Drought doesn’t always = increased wildfire
activity
• Different climate and fuels create unique fire
regimes and thus need unique conditions
• Similar to drought, these conditions occur on
multiple time scales (years to days)…need
alignment

4. Alignment*
• Dry winter(s) -> dry fuels
• Fine fuels don’t grow much, and thus limit
ability for continuous fuels and fire spread
• But with heavy fuels (timber), crown fires
more likely (i.e. King and Rim fires)
• Still need weather to cooperate (i.e. Nevada
last summer)

5. Wildfire Outlooks
• Fire triangle
• Fire outlook triangle: fuels,
weather/climate, typical fire season
• Fuels
– Fuel dryness
– Which fuels are dry
– Fuel loading
• Weather/Climate
– Drought
– Snowpack
– Monsoon/teleconnections
• Typical Fire Season
– What are normal conditions?
– Normal amount of fires, acres burned?

6. Typical Fire Seasons

7. Higher Elevations

8. Precipitation and Temperature

9. California Drought

10. Omegasaurus Rexblockus

11. Teleconnections
• ENSO: El Niño acts to suppress tropical
activity, ITCZ pushes south, decrease in NAM
precipitation
• PNA positive/meridional phase can enhance
precipitation mostly during neutral ENSO
• MJO: can increase precipitation across
western U.S. in phases 6-8
• Essentially…the development and location of
the subtropical ridge

12. Recap of What to Look For
• Dry fuels
• Fuel loading
• Early green-up
• Higher elevations/latitudes with ~average
precipitation, but below average
snow/snowpack
• Forecast weather

13. May Outlook

14. June and July Outlook

15. Summary
• Fire potential is more nuanced then just
‘drought = fire’
• Fuels and atmosphere must align along
multiple timescales for increased or above
average fire potential
• Earlier, longer fire season -> above normal fire
season
• Potentially busy fire season for West Coast
(California, Oregon, Washington)