Floods happen. That’s life in Snohomish County, where it’s not a matter of if but when the rivers will rise. November traditionally is the wettest month, “what we consider the danger zone,” said Mark Murphy of the county emergency management department. Melting early mountain snow and heavy rains in the lowlands cause rivers to swell. December, too, can be flooding prime time. More than 90 percent of damage caused by river flooding since 1975 has occurred during October and December. In those 36 years, the reported cost of flooding has exceeded $90 million.
Events ranked by damage dollar amount.
1. December 1975: $42.4 million — The Snohomish River rampages, killing 3,500 head of livestock and forcing evacuation of more than 300 homes. U.S. 2 closed after dikes break.
2. November 2006: $18.8 million — Damage is widespread along the Snohomish and Stillaguamish rivers.
3. October 2003: $18 million — Two houses are devoured by the Stillaguamish River and Darrington is threatened when the Sauk River spills its bank.
4. December 2006: $5.3 million — The Snohomish and Skykomish rivers heap more misery on flood-battered farms.
5. November 1990: $5 million — Flooding is widespread and arrives less than two weeks after levees were weakened by earlier high water.
Epic flood crests
There are dozens of stream gauges in the county. Four locations dominate the record book of big flood crests. Click an icon on the map to see the details for that location.
View Epic flood crests in Snohomish County in a larger map
Major flood events by day of the month. These dates, in the years cited, represent historic flood-stage crests. Two such events have occurred on Nov. 24. The calendars shown are for 2011.
More historic flood crests
Click on the box below to explore the data.
• Be ready to leave at a moment’s notice.
• Head for higher ground if a flood warning is issued for your area.
• Turn back if floodwaters become ankle-deep.
• Don’t drive on flooded roads. Most cars can be swept away in less than two feet of water.
• Be especially careful at night when it is harder to recognize flood danger.
• Keep three days of water and food available, along with a flashlight, battery-powered radio with extra batteries, a first-aid kit, cell phone with spare batteries, family and emergency contact information, a blanket and medications.
• Before returning to a flooded home, look for loose power lines, damaged gas lines and cracks to the foundation.
• If power lines are down, don’t step in puddles or standing water.
• During cleanup, wear protective clothing, including rubber gloves and boots
Phone numbers during a flood
• 425-388-3653: Flood warning information for Skykomish, Snoqualmie and Snohomish rivers.
• 425-388-3702: Flood warning information for Stillaguamish River.
• 425-388-7500: Road conditions and closures.
• 425-388-5088: Non-emergency requests for assistance and volunteer to help with sandbags.