Climate Change and Fire

Louisa EversBLM Climate Change Coordinator

Spring 2015 FALT Meeting

Climate Change Projections

• Warming year-round but especially for minimum temperatures and in summer

• Little change in annual precipitation but wetter winters and drier summers

• Increased frequency, intensity, and duration of drought

• Fewer but more intense storms, more dry days between storms

• Less snow and earlier snowmelt• Increases in extreme heat, decreases in extreme cold

Observations

• Warming in most seasons with trends in some locations statistically significant

• Little change in annual precipitation, some shifts in seasonality

• Earlier snowmelt• Earlier peak flows and lower base flows• Fewer cold extremes, more warm extremes

Historical Droughts in Oregon and Washington

Types of Drought

• Very low winter precipitation with near normal seasonal temperatures – Dry Drought

• Warm winter with near normal precipitation followed by very warm, dry summer – Hot Drought

• Warm, dry winter followed by near-normal summer – Warm-Dry Drought

• Very warm temperatures through summer and near normal precipitation – Very Hot Drought

Drought Indicators

• Palmer Drought Severity Index– Not scalable– Values used not based on scientific significance– Does not capture drought onset– Performs poorly in mountainous terrain

• Standardized Precipitation Evaporation Index– Scalable– Based on climatological statistics– Captures drought onset– Performs better in mountainous terrain

SPEI Time Series

Oregon-Washington Eastern Washington

3 mon

ths

6 mon

ths

12

mon

ths

Recommended Drought Sites: Drought Monitor

Recommended Drought Sites: UW Drought Monitor

www.hydro.washington.edu/forecast/monitor_west

Recommended Drought Sites: WestWide Drought Tracker

www.wrcc.dri.edu/wwdt/

Energy Limited Fuel Limited

Ponderosa Pine

Fire

Ret

urn

Inte

rval

Cool-Moist Sagebrush

Warm-Dry Sagebrush

Juniper Woodland

Salt Desert Scrub

Dry Mixed Conifer

Moist Mixed Conifer

Lower Subalpine

Upper Subalpine

Implications of Climate ChangeForests Rangelands

Observed Changes in 90th Percentile ERC Values

PSAFire

Season June July August September October

NW01 0.00 -0.10 0.07 0.13 0.21 0.06

NW02 0.36 0.04 0.40 0.57 0.57 0.15

NW03 0.33 -0.04 0.37 0.59 0.49 0.16

NW04 0.42 -0.08 0.46 0.60 0.65 0.61

NW05 0.51 0.38 0.79 0.71 0.86 0.45

NW06 0.56 0.14 0.65 0.73 0.72 0.61

NW07 0.53 0.08 0.49 0.69 0.78 0.67

NW08 0.74 0.41 0.88 0.95 0.86 0.62

NW09 0.62 0.21 0.54 0.99 0.84 0.65

NW10 0.21 -0.17 0.42 0.60 0.16 -0.01

NW11 0.63 0.29 0.68 0.84 0.77 0.67

NW12 0.02 -0.56 0.15 0.37 0.35 -0.22

Projected Changes in the 90th Percentile ERC Values

Questions?