Natural hazard plan getting revisions

Aug. 11--Skagit County's mountains-to-sea landscape means it is at risk of many natural hazards, from common flooding to rare but potentially disastrous volcanic eruptions or massive earthquakes.

The Skagit County Department of Emergency Management maintains plans for responding to such disasters and this spring began the process of updating the Skagit County Natural Hazard Mitigation Plan.

That plan was last updated in 2014 and approved by the Federal Emergency Management Agency in 2015. The new update should be completed in 2020.

Emergency Management calls the plan a "risk reduction roadmap" for the county and communities within it.

"Skagit County has historically faced floods, severe windstorms, winter storm and even volcanic activity," a news release on the update states. "We can't predict when the next natural disaster might strike, but we can plan ahead ... to find ways to minimize the risks."

The county works with city, town, tribal and nonprofit partners on efforts to reduce vulnerability and lessen the impact of natural hazards.

The first meeting on updating the plan was held May 28, with representatives from the county, cities, school districts, dike and drainage districts, as well as tribes, according to a meeting summary.

The group has already decided to remove the avalanche section from the 2020 plan and add one on the influence of climate change on hazards such as drought and wildfire, Emergency Management interim Director Hans Kahl said.

While avalanches have in some cases caused road closures and road damage in east Skagit County, the primary concern is for those skiing, snowshoeing, snowmobiling or otherwise exploring the snow and ice terrain of Mount Baker.

Also, the existing wildfire chapter will be replaced with the Skagit County Community Wildfire Protection Plan, which features new maps with landscape conditions such as soil types and population densities to identify at-risk areas.

The public can give input as the plan is updated. Residents are asked to provide local knowledge of the community's vulnerability to hazards based on past events.

Emergency Management recently launched an online survey soliciting information about what hazards county residents worry about, from dam failure to ice storms. The survey takes about 10 minutes and can be completed anonymously.

The department also recently released a series of posters on its website, regarding the update process and five specific types of natural hazards, for public review.

Comments on the posters can be submitted by email through clicking the links for "feedback" on the web page. Updates will be posted online at skagitcounty.net/dem.

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POTENTIAL HAZARDS OF SKAGIT COUNTY

Drought

Skagit County is susceptible to drought conditions when too little snowpack accumulates during winter. That snowpack sustains streamflows during the summer, or when abnormally hot and dry conditions affect streamflows and groundwater supplies.

The primary concern during a drought is the economic impact on agricultural and forestry industries, according to the existing plan. Water supplies, particularly for private wells that rely on groundwater, are a concern in the event of severe drought conditions.

Drought conditions increase the risk for wildfire, which becomes a greater concern as the region's glaciers recede -- something studies show has been happening since the 1950s.

The county Department of Emergency Management's draft poster on drought says some of the worst that Washington has seen occurred in 1997 and 2001.

A drought during 2015 led to low stream flows and concerns for fish and farms.

Drought conditions are also currently affecting streamflows and resulted in recent irrigation restrictions for farms.

The current drought could add 2019 to the state's top drought years, according to the poster.

Earthquake

Skagit County is at risk of small earthquakes along fault lines throughout the county as well as a major magnitude-9 earthquake along the 600-mile Cascadia Subduction Zone fault beneath the West Coast.

The areas where soil is likely to liquefy and result in landslides are concentrated along the rivers that carve through the county, primarily around the Skagit River, but also around the Samish and Sauk rivers and some tributary streams, according to a county map.

All infrastructure in Skagit County is vulnerable to a large earthquake, according to the current plan. Officials have said that a Cascadia-sized earthquake, which geologists believe occurs every every few hundred years, will likely mean a loss of roads, utilities and communication for an indefinite amount of time.

It would also send tsunami waves to waterfront areas and could damage the dams on the Baker and Skagit rivers. That might mean a surge of flooding following an earthquake.

"It is difficult to identify any part of Skagit County that would not be vulnerable to a large earthquake," the current plan concludes.

Officials have recommended residents prepare to fend for themselves for at least two weeks in case of that kind of earthquake.

Flood

Flooding is perhaps the best-known hazard, as communities along the Skagit River prepare for the possibility of flooding each winter, starting with Flood Awareness Week in October.

The last damaging flood hit in November 2017, when a swelling Skagit River eroded properties in Lyman and damaged homes.

Scientists expect more flooding -- with larger and more frequent floods even outside the typical winter flood season -- due to shifts in precipitation patterns, such as more falling as rain than snow, as well as sea level rise along the shoreline.

FEMA considers the Skagit River "potentially the most damaging river in the state," according to the current plan.

The National Flood Insurance Program is critical for areas of Skagit County, according to the current plan, and has paid billions of dollars for losses in Hamilton, rural Skagit County and other areas.

"In Skagit County, floods are a major threat," the current plan states. Those who live or work in the floodplain "need to recognize that government is not able to totally protect them from the impacts of a flood."

Landslide

Landslides can occur after heavy rain or in combination with flooding or earthquakes.

The most frequent reports of landslides are those that disrupt traffic on state highways, often during the wet winter months.

Landslides have also damaged homes and taken lives in the county, although not for several years.

A home was last destroyed by a landslide in January 2009 in Concrete, according to the current plan. People died in November 1985 near Marblemount and cattle were last killed in February 1996 northeast of Darrington.

Following the major landslide in Snohomish County that killed dozens of Oso residents in March 2014, officials acknowledged that Skagit County has similar terrain.

The current plan states that risk is heightened by increasing residential development in rural areas near steep slopes and bluffs.

Severe weather

Severe local storms are the most likely risk to the county in any given year.

In recent years, the county has experienced abnormal heat, snow storms, coastal storm surge, storm-related flooding, wind storms and heavy rain events.

Skagit County owes its wide range of weather possibilities to its position between the Salish Sea and North Cascades, according to the current plan.

While wind storms in recent years have taken down trees and cut power to homes and businesses throughout the county, those recent events are mild compared to major storms that in 1990 and 1997 resulted in millions of dollars in damages and were declared FEMA disasters, according to the plan.

Flooding and landslides combined also created in January 2011 an almost million-dollar FEMA disaster.

As the global climate warms, more extreme heat and precipitation are expected for the county, meaning more dangerous heat waves, wildfires, flooding and landslides.

Tsunami

Earthquakes can produce tsunamis, and they are possible along the Cascadia Subduction Zone and other parts of the Pacific, such as Alaska or Japan.

Because earthquakes of the magnitude needed to create such a tsunami occur at intervals every several hundred years, the risk is low.

Still, Emergency Management has been preparing for tsunami response, including creating evacuation maps, in partnership with the state and obtaining signs to mark evacuation routes along roads in low-lying areas near the shoreline.

Maps completed so far estimate tsunami waves from a nearby Cascadia earthquake could reach areas in Anacortes and the Samish Flats within about two hours.

Volcano

Two of five active volcanoes in the state border Skagit County: Mount Baker to the north and Glacier Peak to the south.

Neither has erupted in hundreds of years, according to USGS data, but both could in the future.

Eruptions from either -- particularly with resulting mudflows called lahars that could become concentrated along the Skagit River valley -- could severely damage parts of the county.

Geologists have said Concrete and other areas near the volcanoes are most at risk, but will likely get days or weeks of warning before an eruption by earthquakes and changes in the release of steam such as is sometimes visible from a crater on Mount Baker.

Wildfire

Wildfires in Skagit County each summer have historically been small. But with increasing dry conditions, wildfires are occurring more often and becoming larger.

From 1970 to 2001, 638 wildfires were reported in Skagit County, or about 21 per year, according to the current plan. This year, firefighters responded to 21 outdoor burns that got out of control in March alone.

A fire covering about 8,500 acres in the Newhalem area in August 2015 -- shortly after the completion of the current plan -- is the largest one in Skagit County, according to the plan. The second-largest fire burned about 1,200 acres near Marblemount in 1998.

While no major wildfires have been reported so far this summer, Skagit County and surrounding areas of Western Washington have been at above normal risk since May, according to the National Interagency Fire Center's Predictive Services.

-- Reporter Kimberly Cauvel: 360-416-2199, [email protected], Twitter: @Kimberly_SVH, Facebook.com/bykimberlycauvel

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