Extreme Weather

More extreme weather events

Recent climate modeling results indicate that "extreme" weather events may become more common. Rising average temperatures produce a more variable climate system. What can we expect with weather changes? Localized events could include

What creates more extreme weather?
Carbon dioxide (CO2) from cars, industries and power plants trap heat near the earth's surface. More heat means more energy. Adding so much energy to the atmosphere creates the potential for more extremes.

Washington residents experienced weather extremes in the fall of 2006. First, record rains churned up rivers and caused landslides and floods around Western Washington. Then, as the water began to clear, a record cold with ice and snowfall paralyzed parts of the west side of the state. That was closely followed by record gale force winds, 14 deaths, extensive property damage, and days of power outages for 1 million homes and businesses in Washington.

Climatologists say extreme weather events will become more common as our climate heats up.

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Droughts

Current and Seasonal Drought Information and Maps

Multiple droughts since 1971 resulted in dry streams, withered and abandoned crops, dead fish, record low rivers and declining ground water levels. Between 2000 and 2005, Washington experienced two drought emergencies, resulting in drought declarations by Governors Locke and Gregoire.

How will droughts affect us?

Sources: Impacts of Climate Change on Washington's Economy (University of Oregon)

Issue up close: Managing our Water successfully, pg 1

How will the changing weather affect our economy?
The Yakima River Basin produces crops worth about $1 billion annually, mostly from perennial crops. Many of the Yakima Basin perennial crop growers face water shortages. In the low water year of 2001, reduced water allocation resulted in economic losses of $140 - $195 million.

High river flows occurring earlier in the year will result in a 20-40% reduction in water availability by 2050. One potential solution is more reservoir storage, but this is expensive: the proposed Black Rock Reservoir would cost $3.5 to $4 billion.

Federal and state costs of fighting wildfires may exceed $75 million per year by the 2020’s (with a 2 degree warming), and that’s 50% higher than current expenditures. Economic impacts from fires include:

Sources: Agriculture - King Co Climate Conference 2005

Impacts of Climate Change on Washington's Economy (University of Oregon) pg 8

What can be done to protect water supplies?
Conservation practices can help reduce demand for water. Municipalities and irrigation districts need to seek new storage areas to even out the flow and demand for water.

Conserving water for salmon and people cooperatively in the Walla Walla
Industrial water conservation tips

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Floods more extreme & often

Warmer temperatures result in more winter precipitation falling as rain rather than snow throughout much of the Pacific Northwest. This change will result in:

And in rivers that depend on snowmelt (i.e. most rivers in the Pacific Northwest) These trends have already been observed.

In contrast to more rain when we don’t need it, there will be less water when we do need it. Substantial reductions in summer stream flow will adversely affect

These changes are likely to increase existing conflicts among competing water users, made worse by a regional population increase.

Sources: University of Washington – Climate Impacts Group

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More landslides

Rain-soaked soils are prone to slipping, which results in landslides affecting homes, businesses, power lines and transportation routes. More rain could increase the risk and frequency of landslides.

Carlyon Beach: one landslide story
Five years of above average winter rainfall contributed to a massive slide in the Hunter Point, Carlyon Beach area of Thurston County in February 1999.

Homes and roads were built on an ancient 60-acre slide. Forty-one homes were damaged by the slide. Thirty three homes in the area were "red-tagged" or declared uninhabitable. Homeowners were requested to evacuate because of severe structural damage. The cost for the proposed repairs was between $4 and $39 million - with no guarantees.

The landslide stretched 3,000 feet along the Squaxin Passage shoreline and extended inland 900 feet. The steep slopes of the landslide reached heights of 15 feet.

A Carlyon Beach area home once valued at $200,000 dropped to a value of $1,000. Ninety other properties in the Hunter Point, Carlyon Beach area dropped in value to almost nothing.

Landslides around the state
Slides over Hwy 12 and Hwy 101 have closed routes and cost millions to clear. The City of Seattle attributes cost of $20 million to landslides caused by major storms during the winter of 1996-97.

Sources: Impacts of Climate Change on Washington's Economy (University of Oregon) p.77

Landslides & Debris Flow, Ready.gov, Federal Emergency Management Agency. What to do before, during and after a landslide.

Carlyon Beach, Hunter Point Slide

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More stormwater = more pollution

More information from Ecology: Stormwater

More precipitation falling as rain rather than snow quickly runs off the land, especially over paved surfaces, and areas cleared of forest or natural vegetation. In a warmer climate, precipitation falling as rain could increase fall and winter flooding in susceptible river basins.

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Earlier river runoff

As the spring thaws come earlier and faster, the peak period for snow melt could move back weeks or months. This would result in less summer water when it’s needed most for crops, fish, cities and hydropower generation.

Urban water supply systems that rely on storage of water in mountain snow pack will see less water coming into their reservoirs in late spring/early summer. This will be combined with an increased demand for water caused by higher temperatures. For some systems, these impacts will be substantial.

Sources: Climate Impacts on Pacific NW Water Resources – (University of Washington Climate Impacts Group)

Impacts of Climate Change on Washington's Economy (University of Oregon)

US Water Supply and Distribution fact sheet (University of Michigan - Center for Sustainable Systems)

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Changing growing season

With a warming climate, the growing season for some plants may be extended. The last frost would come earlier in the spring and first frost would come later in the fall. However, this advantage can be erased if there is limited water to nourish forests and crops during hot weather.

Studies in Washington wine country conclude that more frequent series of extreme hot or cold days can result in damage and loss, even if the rest of the season is more moderate.

Warmer winters allow forest and crop pests to reproduce longer and suffer less winter die offs, so pest populations can boom. This is already happening in Canada and even NE Washington forests where pine bark beetles are rapidly devastating large tracts of forests.

Ecosystem changes from shifting seasons can

Source: Climate Impacts on Washington's Hydropower, Water Supply, Forests, Fish and Agriculture (University of Washington – Climate Impacts Group) pg 34

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Multiple emergency response needs

Extreme weather across the state can

Delayed emergency response can become more common.

The storm of December 2006 is considered more devastating than that of the January 20, 1993 storm, which left five people dead, at least 79 homes destroyed and about $130 million in damage.

Damages from the 2006 storm have yet to be assessed, but the death toll appears to be higher, and the impact on the power grid appears to be more severe. Seattle City Light reconnected 175,000 buildings, compared with 110,000 in the Inauguration Day storm. Puget Sound Energy reported more damage to major transmission lines. One million homes and businesses were without power for up to a week while low temperatures hovered in the mid 20s.

Source: KOMO-TV