Marin King Tide Outlook
Flood outlook for four Marin streets that flood on big tides. It adds this fall's El Niño sea-level bump (the Kelvin wave) to NOAA's tide predictions, then checks the result against flood thresholds set from resident photos.
Next flood tides by location
The highest tide each day, with the local high time. Storm surge is not included, so a storm on any of these days adds more water.
14-day outlook
Each cell is that day's highest tide at the San Francisco gauge with the current anomaly added. The color is the flood level at that location. Hover or tap a cell for details. Beyond about two weeks, treat it as a rough guide: the anomaly can grow or fade.
Daily high tide forecast
The highest tide each day at the San Francisco gauge: NOAA's prediction, and the forecast with today's anomaly added. The shaded band is ±0.25 ft of uncertainty in the anomaly.
Show as table
Kelvin wave watch: anomaly along the coast
Daily average of the measured water level minus the predicted tide over the last three weeks. Slow buildups tend to show up in San Diego first and reach San Francisco about three days later. Storm spikes don't follow that pattern.
Show as table
How this works, and its limits
- Tide: NOAA's hourly predictions for the San Francisco gauge (9414290), in feet above mean lower low water. All thresholds use that same scale.
- Anomaly: measured minus predicted water level at San Francisco, averaged over the hour either side of the last two high tides (or the last 25 hours if that's unavailable). It's carried forward unchanged, which holds well for slow Kelvin wave buildups but says nothing about storms.
- Thresholds: each street's flood lines come from a 1-meter lidar flood model, SFEI's Bay shoreline data, resident photos (Jan 1–3, 2026 and Oct 27–29, 2026) and the WET app's flood lines. They are estimates. Pump stations, storm drains and rain all shift them.
- Not included: storm surge, wind and rain. During a storm, check the NWS Bay Area coastal flood advisories.
- This is a community project, not an official warning. Don't drive through floodwater.