Severe Storms risk in Washington

Severe Storms in Washington: What to Expect

Washington state sits in a region where severe thunderstorms are less frequent than in the midwestern United States, but they still occur. The National Risk Index rates severe storm risk in Washington as relatively low (level 2 out of 5). This means that while the probability of a damaging storm in any given year is modest, the consequences can be significant when one does hit.

Geography plays a large role in where severe storms develop. The Cascade Mountains split the state into two very different weather zones. West of the Cascades, the maritime climate keeps summers mild and thunderstorms are rare, occurring mostly in late spring and early fall. East of the Cascades, the climate is drier and more continental, with a higher frequency of thunderstorms, particularly from May through August. This is also the area most prone to large hail, damaging winds, and the occasional tornado.

According to the NOAA Storm Prediction Center, Washington typically sees only a few tornadoes per year, and those are almost always weak (EF0 or EF1). However, severe thunderstorms can produce wind gusts over 58 mph and hail larger than one inch, which are enough to damage roofs, siding, and vehicles.

Another important aspect is lightning. While lightning strikes are less common in western Washington, the eastern half of the state sees more frequent thunderstorms, and lightning can spark wildfires in the dry summer months. The Ready.gov guide on thunderstorms and lightning provides additional details on how to stay safe.

How Severe Storms Affect Homes

When a severe thunderstorm hits your area, the most common types of property damage come from high winds, hail, and lightning. Wind gusts from severe storms can rip shingles off roofs, break windows, or topple trees onto homes and vehicles. Hail can dent metal roofs, damage asphalt shingles, and crack skylights. Lightning can ignite fires inside a home or cause power surges that damage electronics and appliances.

In Washington, falling trees are a particular concern because many neighborhoods have mature evergreens, especially west of the Cascades. During a severe storm, saturated soil and strong winds can cause these large trees to uproot and fall on houses, fences, and power lines. Power outages are also a common impact, leading to food spoilage and, in winter, heating failures.

Insurance is an important consideration for homeowners. Most standard homeowners insurance policies cover damage from wind, hail, and lightning, but not from flooding. If a severe storm brings heavy rain that causes water to enter your home through a storm surge or overflow, that would be considered flooding and is typically excluded from standard policies. The Washington Emergency Management Division encourages homeowners to review their policies and consider separate flood insurance if they live in a flood-prone area.

How to Prepare Your Home for Severe Storms

Preparation can substantially reduce the damage a severe storm inflicts on your home. Here are some practical steps you can take:

• Inspect and maintain your roof. Check for loose or missing shingles, and make sure flashing around chimneys and vents is sealed. A sturdy roof is your first line of defense.
• Trim trees and remove dead branches. Keep limbs away from your roofline and windows. If a tree is close to your home, consider consulting an arborist to assess its health.
• Secure outdoor items. Patio furniture, grills, trash cans, and toys can become projectiles in high winds. Bring them inside or tie them down when a storm is forecast.
• Reinforce the garage door. A large garage door can bow or collapse under strong wind pressure. Use a bracing kit or install a wind-rated door.
• Install surge protectors. Lightning can cause power surges that damage sensitive electronics. Use plug-in surge protectors or a whole-house surge protector.
• Consider impact-resistant windows or shutters. If you live in an area prone to hailstorms or high winds, these can protect glass from breakage.
• Prepare an emergency kit. Include non-perishable food, water, a flashlight, batteries, a weather radio, and essential medications. Store it in a convenient location.
• Know your alerts. Sign up for emergency alerts from your county or the Washington Emergency Management Division, and pay attention to weather watches and warnings from the National Weather Service.

Frequently Asked Questions

Do severe thunderstorms happen in western Washington?

Yes, but they are much rarer than east of the Cascades. The maritime climate west of the mountains limits the heat and instability needed for strong thunderstorms. Still, spring and fall cold fronts can trigger a few severe storms, particularly in the Puget Sound area. The main threat is wind, with some lightning and small hail, but tornadoes are very rare.

What is the typical severe storm season in Washington?

Thunderstorm activity peaks from May through August, mainly in the eastern and central parts of the state. This is the time when warm, dry air and afternoon heating can produce strong updrafts. However, windstorms associated with mid-latitude cyclones can occur in the fall and winter, especially in western Washington, and can cause significant damage even though they are not classified as severe thunderstorms.

Should I buy flood insurance if I'm worried about severe storms?

Yes, if you live in a flood-prone area. Severe thunderstorms can produce heavy rainfall that overwhelms drainage systems, and standard homeowners insurance does not cover flooding. The Washington Emergency Management Division recommends checking your flood risk and considering a separate flood insurance policy through the National Flood Insurance Program. Visit FloodSmart.gov or consult your insurance agent for more details.

Official Resources

• Washington Emergency Management Division
• NOAA Storm Prediction Center
• National Weather Service – Thunderstorm Safety
• Ready.gov – Thunderstorms and Lightning