Corte Madera Creek Tides

Estimated high tides at the Bon Air Bridge –

Nuisance flooding 7.0–7.5 ft Minor street flooding 7.5–8.0 ft Major flooding & road closures 8.0+ ft 100-year tide 9.5+ ft Green values are measured peaks (click for that day's chart) (+0.2) is forecast air pressure's effect, included in the height (next 7 days) “NOAA 6.9, +0.9”: NOAA's Corte Madera prediction and how much the estimate adds (2+ months ahead)

Heights are estimated peaks at the Bon Air Bridge gauge (ft NAVD88, the scale the daily chart's flood lines use), from NOAA's San Francisco tide predictions calibrated to the past year of measured Bon Air peaks and the last 30 days' sea level. How far the bay is running above or below normal usually lasts through the season and fades by spring, so further ahead the estimates carry less of it (in 55 years of San Francisco records, an October anomaly was ~80% left in January and ~20% by April). Times are NOAA's Corte Madera predicted high plus the creek's usual lag. A day's color is the flood level its highest tide is estimated to reach (or measured, once past); estimates typically miss by about 0.3 ft either way. The percentage is the chance of reaching the next level up. A day's second high tide is only listed when it's 6.5 ft or more.

Storms, low pressure and south wind can add a foot or more and can't be forecast weeks ahead, so check the daily chart in the days before a colored date. For the next 7 days the estimates include the forecast air pressure (about 0.4 inch per millibar below normal, less further ahead), shown in parentheses; in 2026 that halved the miss on tides with a strong high or low coming. Tested on Dec 2024 – Oct 2026 a month ahead: 89% of days colored nuisance reached 7.0 ft, and 82% of days colored minor reached 7.5 ft. Uncolored days estimated at 6.8–7.0 ft reached 7.0 ft 40% of the time; lower days, 4%. No tide in that period was estimated a month ahead to reach 8.0 ft, so the major flooding color is untested. When sea level climbs fast the estimates lag: in October 2026, as the bay rose about half a foot above its already high level, estimates made a month ahead came in about 0.6 ft low.

Data: NOAA and Marin County Flood Control.