Natural Disasters in Washington: What Is the Risk?

Over 7.7 million people live in Washington State. Many of these people have experienced natural disasters in the state firsthand or had to evacuate because of disasters. However, many Washington residents don’t realize just how many types of natural disasters can occur in the state.

This analysis covers what natural disasters occur in Washington, the worst natural disasters to hit the state since 2000, and what residents can do to prepare.

Is Washington At Risk of Natural Disasters?

Compared to the rest of the United States, Washington has a high risk of natural disasters. Excluding COVID, Washington has had 135 disaster declarations since 2000. Of these, 26 were declared major disasters. 

Washington is also sometimes hit by natural disasters, which cause more than $1 billion in damages. Since 2000, more than 24 separate $1-billion events have affected Washington. Most of these events were wildfires or droughts.

Worst Natural Disasters in Washington By Cost (Since 2000)

1. Summer-Fall 2018 Western Wildfires: $28.3 billion
2. February 2021 Winter Storm and Cold Wave: $25.6 billion
3. 2022 Drought and Heat Wave: $22.2 billion
4. Summer-Fall 2017 Western Wildfires: $22 billion
5. Fall 2020 Western Wildfires: $18.9 billion

Worst Natural Disasters in Washington By Deaths (Since 2000)

1. February 2021 Winter Storm and Cold Wave: 262 deaths
2. 2021 Drought and Heat Wave: 229 deaths
3. 2022 Drought and Heat Wave: 136 deaths
4. Summer-Fall 2018 Western Wildfires: 106 deaths
5. Summer-Fall 2017 Western Wildfires: 54 deaths

*Cost and death tolls are for the entire disaster, including in other states affected.

Most Common Natural Disasters in Washington State

1. Earthquakes

Washington doesn’t have high-magnitude earthquakes as frequently as California. However, it is at high risk of catastrophic megaquakes.

The state is located in the Cascadian Subduction Zone, a 680-mile stretch from Northern California to British Columbia, and capable of earthquakes 30x more powerful than the San Andreas Fault. These quakes could reach or even exceed magnitude 9.0.

The Cascadian Subduction Zone extends about 70-100 miles into the Pacific Coast. It is part of the Pacific “Ring of Fire” – an area where more than 90% of all earthquakes in the world occur. These earthquakes can produce devastating tsunamis. Washington’s major ports, businesses, and coastal populations are at risk.

The last 9.0 magnitude earthquake occurred in the Cascadian Subduction Zone in 1700. The quake caused the coastline to drop several feet and caused a tsunami so large that it caused destruction in Japan.

More recently, Washington experienced a magnitude 6.8 earthquake in 2001. That quake occurred just 36 miles from Seattle.

2. Flooding

Compared with the United States, Washington State is at high risk for flooding. Approximately 11.3% of all properties in the state are at substantial risk of floods. Due to climate change, this number is expected to increase to 12% by 2050.

Washington has over 70,000 miles of rivers and streams. In winter and spring, it is common for these waterways to flood from heavy rains and snowmelt. In the summertime, flash flooding is common in Eastern Washington.  

Which Areas of Washington Are Most At-Risk of Flooding?

Floods can occur in all parts of Washington, but some areas of the state are particularly at-risk. Below are the areas of Washington with the greatest percentage of properties likely to experience flooding (based on 2020 calculations). 

• Toppenish: 100%
• Fife: 96%
• Finley: 90%
• Pacific: 88%
• Longview: 87%
• Hoquiam: 82%
• North Bend: 81%
• Orting: 79%
• Centrallia: 75%
• Sedro_woolley: 74%

In addition to these areas, there are many major cities and towns in Oregon where thousands of properties are at risk. This includes nearly 14,000 properties in Seattle, 9,500 properties in Spokane, and over 7,000 in Walla Walla.

3. Heavy Snowfall and Winter Storms

Washington only gets an average of 16 inches of snowfall per year. The coastal areas of Washington get almost no snow, whereas the eastern half of the state gets an average of 37 to 51 inches per year.

While not common, Washington can sometimes have winter storms. These winter storms can cause widespread power outages. Carbon monoxide poisoning can occur when residents improperly use generators. 

4. Heat Waves and Droughts

Washington doesn’t have many days of what the National Weather Service calls “dangerous” heat: days where the heat index is 103F. However, that doesn’t mean Oregon isn’t at risk of high temperatures. Over the next few decades, the “Local Hot Days” risk in Washington is expected to increase. 

Local Hot Days are “Days at or above the 98th percentile temperature, or the temperature that an area could expect to see on the hottest 7 days of the year.” Essentially, Local Hot Days factor in what temperatures a local population is used to experiencing.  

Since many people in Washington don’t have air conditioning, increased temperatures – even when they aren’t considered “dangerous” – can have severe implications. Health problems like strokes increase, and heat-related deaths are more likely to occur. 

Because Washington is so unused to and unprepared for high temperatures, the 2021 Western North America heat wave hit the state particularly hard. Seattle reached temperatures of 108F. There were at least 100 heat-related deaths in the state.  

All parts of Washington are expected to see more Local Hot Days over the next few decades. However, Juan County is particularly at risk. In 2053, Juan County can expect to see 20 consecutive days of temperatures at or above 76.9℉.

Droughts often accompany heat waves. These droughts can take a huge toll on Washington’s agricultural economy and increase the already-high risk of wildfires.