Flood warning system and alerts

Information and resources to warn you of potential flooding on King County rivers. Early warning can give you time to prepare before flooding occurs.

The King County Flood Warning System can warn you about rising floodwaters on major rivers. This allows you to prepare before serious flooding occurs. In most places, the warning system provides at least 2 hours lead time before floodwaters reach damaging levels.

Flooding and high water are most common from October through April during periods of heavy rainfall or rapid snowmelt. Historically, King County rivers have flooded in every month but August.

There are 3 ways you can get information about rising floodwaters:

Call the King County Flood Warning Center
Sign up for flood alerts
Use our Flood Warning App

When does flooding and high water typically happen in King County?

Flooding and high water are most common from October through April during periods of heavy rainfall or rapid snowmelt. Historically, King County rivers have flooded in every month but August.

What other information is available from the Flood Warning Center?

King County works closely with the National Weather Service to obtain forecast information used to make flood predictions. Close coordination occurs with King County’s Office of Emergency Management, Roads, and other agencies to obtain up-to-date information about problems sites, road closures, evacuations and other emergency services. Coordination also occurs with the U.S. Army Corps of Engineers and Seattle Public Utilities regarding dam operations. Personnel at the Center are available to answer questions and help interpret gage readings during a flood event. Current river and flood information is always available through the phone menu system.

Call the Flood Warning Center at: 206-296-8200 or 800-945-9263.

Water churns making white caps in a creek.

King County Flood Warning Information Center

We work closely with the National Weather Service to obtain forecast information used to make flood predictions. We also coordinate with the U.S. Army Corps of Engineers and Seattle Public Utilities about dam operations.

Our internal groups, including Emergency Management and Roads, coordinate to maintain up-to-date information about:

Problem sites
Road closures
Evacuations and other emergency services

Call the Information Center to:

Hear current river flow data
Get information about sandbags
Learn background information on flood phases
Connect to the River and Floodplain Management section during business hours

During flood events, we provide the latest condition information, answer questions, and interpret gage readings.

If you have a flood emergency, please call 911.

You can call the Information Center 24/7

Live representatives answer calls during flood events. You can request an interpreter if you need one.

206-296-8200

Toll free: 800-945-9263

Sign up for Flood Alerts

Flood Alerts can give you more time to prepare before serious flooding occurs.

It is free to sign up. You can choose to get alerts by email, SMS text message, or phone call.

You can also:

Select the rivers that affect you. Our Flood Alert System only issues alerts for the Snoqulamie Basin and these 6 major rivers:
- Cedar River
- Green River
- Issaquah Creek
- South Fork Skykomish River
- Tolt River
- White River
Select the flood phases that are of interest to you (there are 3 total):
- Phase 2: Minor flooding in some areas
- Phase 3: Moderate flooding in some areas
- Phase 4: Major flooding in areas; may include road closures and other impacts

For each river you sign up for, you will also receive "River emergency" alerts. These will be used for any flood-related emergency, regardless of phase.

If you receive a "River emergency" alert, please check your local news media, or contact the our Flood Information Center at 206-296-8200 or 800-945-9263.

FAQs about Flood alerts

You can sign up for as many of the rivers and flood phases as you like.

Note that the 3 public phase alerts for each river are issued separately. If you want to get alerts for each phase on a river, check all three boxes for that river.

The Flood Alert System only issues alerts for the Snoqualmie Basin and these major rivers in King County:

Cedar River
Green River
Issaquah Creek
South Fork Skykomish River
Tolt River
White River

Check current river conditions

The King County Flood Warning App helps you stay informed about conditions on seven rivers and Issaquah Creek. Launch the app to view:

Current river conditions
Forecasts
Interactive graphs
Information in many languages through Google Translate

You can also install the app to use on your computer or mobile devices. The application downloads data from the U.S. Geological Survey, National Weather Service, and Northwest River Forecast Center about every 10 minutes. The app was funded by the King County Flood Control District and developed by King County.

Launch the Flood Warning App

About the alert messages

Where do the messages come from?

King County has contracted with the vendor Konexus for message delivery. E-mail and text messages will come from the address msg@mail1.alertsense.com – you may need to add this address to your "allowed sender" list or adjust spam-blockers to receive the alerts. Phone messages will come from the phone number 206-296-8200.

Will I get phase alerts when the river levels go down?

No, the Phase 2, 3, and 4 alerts are only issued as the rivers rise past the phase thresholds. They are not re-sent as the rivers recede back past the thresholds again. However, if a river falls and the phase is lowered, and then later the river rises above the next threshold again, a second alert may be issued.

Will I receive any other alerts besides the ones I signed up for?

You will also be added to a "River emergency" list for each river you signed up for. The "River emergency" alerts will be used for any flood-related emergency. If you receive a "River emergency" alert, please check your local news media, King County flood services, or call 206-296-8200 or 800-945-9263.

What does "River emergency" mean?

The "River emergency" alerts will be sent for emergency conditions that do not fall within a Phase 2, Phase 3, or Phase 4 declaration. Possible examples of a “River emergency” alert could include events such as levees being damaged or overtopped, a chemical spill into a river, etc. Because of the wide range of possible emergencies, the alerts themselves are not specific. If you receive a "River emergency" alert, you will need to consult other sources (e.g., news media or the Web) for more information.

An example of a "River emergency" alert:

"This message is to inform you of emergency conditions associated with the Tolt River. For more information, see King County flood services or call 800-945-9263."

How do I sign up for the "River emergency" alerts?

You are automatically signed up for emergency alerts for any rivers you sign up for. For example, if you sign up for Cedar River Phase 2, 3, or 4 you will also be added to the Cedar River Emergency alert list.

Do you issue alerts for other rivers or streams?

The Flood Alert System only issues alerts for six major rivers in King County: Cedar River, Green River, Issaquah Creek, South Fork Skykomish River, Tolt River, White River, and the Snoqualmie Basin. River gage data is available online for other river systems (e.g. Skykomish River and Raging River) at King County flood services.

About the Sign-Up Form

How many alert lists can I sign up for?

You can sign up for as many of the rivers and flood phases as you like.

Note that the three public phase alerts for each river are issued separately. If you want to get alerts for each phase on a river, check all three boxes for that river. Learn more about the phases of flood alerts on our Flood Warning System page.

How will I know I'm signed up?

If you signed up on the webpage (https://green.kingcounty.gov/floodalertsystem), you can log in using your e-mail address and password to confirm your subscriptions. If you don't remember your password, there is a password reminder feature which will e-mail your password to you.

If you no longer have access to the e-mail address you used to sign up, don't have e-mail, or need further assistance, you can call 206-477-4899.

Why do I keep getting a "server busy" message?

You may be redirected to this page for a number of reasons – in order to serve as many people as possible, our subscription form limits the number of accounts you can sign up for at once. If you need to sign up multiple people for alerts (for example, family or co-workers), you can add more the next day or call 206-477-4899. You may also see this page due to a large number of people signing up at once. Please try again later.

Is my contact information kept private?

Please see the King County’s privacy policy. Your contact information is provided to our message-delivery vendor, Konexus for the sole purpose of delivering flood alerts by e-mail, text message, and/or phone. The county does not sell or rent information to others and takes steps to safeguard your information. However, as a public entity, your information may be subject to public disclosure as directed by local, state, or federal laws.