Marin's creeks are part of what makes its towns beautiful, and part of why some neighborhoods take on water in big storms. If you live in the Ross Valley along Corte Madera Creek and its tributaries, near San Rafael Creek, or along Novato Creek, a strong El Niño winter is a good reason to revisit your flood plan.
As of the Climate Prediction Center's October 8, 2026 ENSO discussion, an El Niño Advisory is in effect, and NOAA says a strong-to-very strong El Niño is likely through January–March 2027. NOAA is also careful to say that a stronger event makes El Niño-like impacts more likely, not guaranteed. El Niño winters have historically tilted Northern California toward wetter conditions, but individual seasons vary, and no outlook can tell you when or where a specific storm will hit. Watch the CPC seasonal outlooks and the National Weather Service Bay Area office for forecasts as the season unfolds.
Creek flooding happens when heavy rain falls on saturated hillsides faster than channels can carry it to the bay. High tides can make it worse in lower reaches, because water backs up where creeks meet tidal areas. The Marin County Watershed Program has information about local watersheds, flood protection projects and preparedness.
Get alerts. Sign up for AlertMarin and choose flooding and weather alert groups. Add every Marin address you care about. The county recommends setting the AlertMarin number to bypass Do Not Disturb so overnight alerts reach you.
Make a move-up plan. Decide in advance what you'll move upstairs or onto shelves if water threatens: important documents, electronics, medications, keepsakes. Keep them in waterproof bins in the meantime.
Sandbags and barriers. Many Marin cities and towns provide sandbag locations during the rainy season. Check your city or town's website before storms. Sandbags help direct shallow water away from doors and garage entrances; they aren't a dam.
Check backflow and drains. If you've had sewer backups during storms, ask a plumber about a backwater valve. Clear area drains and the storm drain in front of your house.
Protect utilities. Know how to shut off electricity and gas. If your furnace, water heater or electrical panel is in a basement or low garage, ask a professional whether elevating them is practical.
Insurance. Standard homeowners policies generally don't cover outside flooding. Flood insurance through the NFIP (FloodSmart.gov) or private carriers usually has a waiting period, so look into it before the season, not when a storm is forecast.
Many creekside homes in the Ross Valley have crawlspaces. After a flood, water can sit under the house long after the street is dry, raising humidity and feeding mold on floor joists. Have the crawlspace checked and dried, and look at whether the vapor barrier and vents need repair. Our sister site covers crawlspace mold in older Marin homes.
If your home floods repeatedly, ask about longer-term options: regrading, drainage improvements, flood vents, elevating utilities, or flood-resistant materials on lower levels. Your city or town may also be able to tell you about local flood protection projects.
Talk through a plan with everyone in the household before the season. Decide where you'd go if an evacuation warning is issued: a friend's house uphill, a relative outside the flood area, or a hotel. Decide who picks up children from school if roads are flooded, and how you'll reach each other if cell service is spotty. Keep a go-bag with medications, chargers, copies of important documents, cash, and pet supplies. If anyone in your home has mobility needs or relies on powered medical equipment, plan extra time and backup power. AlertMarin's evacuation warnings are designed to give people who need more time a head start, so treat them seriously.
If your home took on water, submit a request and we'll connect you with an independent local restoration provider. And read the first 24 hours after water damage for a step-by-step guide.
Usually not; outside flooding typically requires a separate flood policy, often with a waiting period.
AlertMarin sends calls, texts or emails for emergencies like floods at the Marin addresses you register.
No. Ready.gov advises never walking or driving through floodwater.
Medications, chargers, documents, cash, water, snacks, pet supplies and a flashlight.
They help divert shallow water from doors but aren't a dam.
This article is general information, not legal, insurance or medical advice. Sources are linked in the text.