AP Photo/John Froschauer

Puget Sound

June 2021

The Changing Climate of WA State:

Drought and Wildfire Implications

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Regional Historical Trends

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Climate Change Projections

Topics

• Heatwave and drought of 2021
• Observed trends in heat, floods, wildfires/air pollution
• Climate model-based projections

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Excerpt from the “Main Findings” in a journal article

by Philip et al. (2021) about the PNW heat wave of 2021

Was an all-time high temperature record set in WA state in the summer of 2021?

Considerably higher dewpoints in irrigated regions of

eastern WA, with implications for heat stress on humans

from Miralles et al. (NYAS, 2018)

Streamflow

1920-2012 Temperature Trends

Squares aren’t significant linear trends; circles are significant at 95%

Abatzoglou et al. 2014 (J. Climate)

WA State Summer

Maximum Temperatures

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WA State Summer

Minimum Temperatures

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WA State Winter

Minimum Temperatures

Summer Temperature Trends

https://climate.washington.edu/climate-data/trendanalysisapp/

WA Statewide

Trends in End of Winter (1 Apr) Snow Water Equivalent (SWE)

Beaver Pass in North Cascades

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WA State Precipitation in Summer

Magnitudes of Greatest

1-Day Streamflows

Snow-dominant

(Spring Melt)

Rain-dominant

(Winter Runoff)

Mixed – High Flows

Winter & Spring

Data Sets for Student Analysis

• NOAA’s Climate at a Glance for temperature and precipitation time series: https://www.ncdc.noaa.gov/cag/global/time-series
• Provide or have students download various data sets
• Exercises comparing data sets for different locations or different parameters (e.g, maximum versus minimum temperature, or winter versus summer data) could help illustrate what is happening and give students some experience handling and plotting data
• For older students, simple statistical analyses (e.g., sensitivity of trends to start and end points) might be instructive

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• NW Climate Toolbox (https://climatetoolbox.org/) represents a very comprehensive compendium of climate information for teachers including data sets that can be used in student explorations

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SST Anomalies Offshore of the Pacific NW Northwest

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HadSST (Degrees C)

40-50 N, 140-125 W

The Winter of 2014-15

Capital Press – March 2015

Excerpt from “2015 Drought and Agriculture: A Study

by the Washington State Department of Agriculture”

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Estimated Short-term Economic Damage: $633-773 Million

NW Raspberry Harvest down 30% due to 2021 Heat Wave

National Interagency Fire Center

Holden et al. (2018)

Changes in Wildfire Acres (1984-2015)

Additional measures of

aridity have also changed

in recent decades and

have been linked to

increases in annual totals

of acres burned in the

western US

Puget Sound Clean Air Agency

Mean Concentrations

(ug/m3 during Oct-Feb)

SO,

IS THIS

YOUR FIRST

WINTER HERE IN OLYMPIA?

I DON’T CARE WHAT THEY SAY, THIS GLOBAL WARMING SCARE IS JUST A BUNCH OF LOONY LEFT-WING ENVIRONMENTAL ANTI-GROWTH HYPE!

2022

Modeled Change in Temperature by

the Middle of the

21^st Century

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Dec-Jan-Feb

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Jun-Jul-Aug

Modeled Change

in Precipitation

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Nov-Dec-Jan

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Jun-Jul-Aug

Modeled Temperature

in the Pac NW

Increases in Atmospheric River Frequency and Intensity – Espinoza et al. (2018)

When will the climate change signal in July

streamflow exceed the interannual variability?

Water Challenges

• Summer Demand versus Winter Floods
• Infrastructure (e.g., Reservoirs)
• Legal Issues
• Hydropower
• Habitats/Environmental Concerns
• Recreation/Tourism
• Groundwater Withdrawals

Steve Ringman/Seattle Times

Late Spring 2022 in WA State

Final Remarks

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• By one measure, the heat wave of 2021 was on the order of a 1000-year event for the Pacific NW, and based on accepted methods involving extreme events, it was made much more likely by climate change.
• Low minimum temperatures in winter are becoming less severe and frequent; minimum temperatures in summer are rising
• Winter precipitation is liable to increase (but not yet evident in the observations); a tendency for greater peak floods in many mountain watersheds
• Summer droughts are projected to become more frequent
• Air pollution in winter is declining; the summers are getting smokier due to greater wildfire activity in the western US

Questions?

• OWSC website: www.climate.washington.edu
• email: climate@atmos.washington.edu
• Newsletter: www.climate.washington.edu/newsletter

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• phone: 206-543-3145 (Karin)
• phone: 206-525-7363 (Nick)

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The mouth

of the White

Salmon River

in July 2015

Large Drop in Snowpack in the Mountains by End of Century

UW Climate Impacts Group

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West Nile Virus (WNV)

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Harmful Algal Blooms

S. Moore NOAA/NWFSC

References

Dalton, M.M., P.W. Mote, and A.K. Snover [Eds.]. 2013. Climate Change

in the Northwest: Implications for Our Landscapes, Waters, and Communities. Washington, DC: Island Press. Available at http://www.cascadiaconsulting.com/uploads/pdf/climate_change_in_the_northwest_oct2013z.pdf

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US Bureau of Reclamation (2016): SECURE Water Act Section 9503(c) – Reclamation Climate Change and Water 2016. Available at http://www.usbr.gov/climate/secure/

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US Environmental Protection Agency (2016): Climate Impacts in the Northwest. Available at https://www.epa.gov/climate-impacts/climate-impacts-northwest#Reference2

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