Flood Zones and Flood Risk in Corte Madera and Larkspur, California

A Documented Flood History, Not a New Story

Corte Madera Creek has a real, sourced flood history stretching back over a century: roughly a dozen damaging floods of the valley floor between 1914 and 1960 alone -- about one every four years -- and eight major-damage floods in the last hundred years, six of them occurring even after the Army Corps of Engineers converted stretches of the creek to a deep, rectangular concrete channel starting in the 1960s specifically to reduce flooding. Notable individual events include the January 1982 flood, when peak creek flow hit roughly 6,000 cubic feet per second, and 100-year storm events in 1982, 1986, and 2006, with the New Year's 2005-06 flood ranking among the largest on record for the watershed. This is not a market where flood risk is a recent discovery; it's a documented, repeated pattern the towns and the Army Corps have been actively managing, with mixed success, for more than 60 years.

January 2-3, 2026: The Most Recent, Best-Documented Event

On January 2-3, 2026, a near-record king tide combined with heavy rain falling on already-saturated ground to flood U.S. Highway 101 in Corte Madera two to three feet deep at the Lucky Drive interchange, closing the freeway in both directions for roughly six hours on a Saturday afternoon and forcing traffic to divert off the highway at Sir Francis Drake Boulevard. Floodwaters spilled over levees, covered Bay Trail bike paths, and damaged private homes and businesses in the Larkspur Landing/Marina neighborhood along Corte Madera Creek, as well as Corte Madera's own town maintenance yard. U.S. Representative Jared Huffman toured the flooded area afterward and said Marin County was "caught off guard" by the storm surge, and reporting from the same month described a permanent Highway 101 flooding fix for this stretch as still years away.

This page treats that event as the current, real baseline for how seriously to weigh flood risk in this market -- not a freak occurrence, but the most recent instance of a well-documented, recurring pattern. A buyer should ask directly whether a specific property was affected by the January 2026 event, and to what depth, rather than relying only on FEMA's static mapped zones.

FEMA Flood Zones: AE, VE, and a Real Base Flood Elevation

The Town of Corte Madera's own flood-protection materials describe its Special Flood Hazard Area as consisting of properties within FEMA zones AE and VE. Zone AE covers the 1%-annual-chance (commonly called "100-year") floodplain determined by detailed hydraulic analysis, with a Base Flood Elevation shown at selected intervals; in Corte Madera's tidal areas, that Base Flood Elevation runs near 10 feet above the North American Vertical Datum of 1988 (NAVD88), per the town's own materials. A property mapped in zone AE or VE with a federally backed mortgage generally faces a mandatory flood-insurance purchase requirement. This page does not state a specific flood zone letter for any individual parcel in either city, since that determination depends on the exact address and current FEMA mapping, which is periodically revised as new elevation and hydrology data become available.

Larkspur's own floodplain management program covers the portions of Larkspur (including the incorporated part of Greenbrae) subject to the same tidal and creek flood dynamics, though this page did not confirm Larkspur-specific flood-zone-boundary detail at the same depth as Corte Madera's own published materials -- a genuine, disclosed gap. Confirm a specific property's flood-zone status directly with FEMA's Flood Map Service Center or the relevant city's planning department.

The Corte Madera Creek Flood Risk Management Project: A Real, Ongoing Effort, Paused

The Army Corps of Engineers and the Marin County Flood Control District have an active, named project -- the Corte Madera Creek Flood Risk Management Project -- designed to provide increased flood protection, up to a 25-year level, for the upstream communities of Ross and Kentfield, while also improving fish passage and habitat along the creek. Some components have already been completed, but as of the most recent available reporting, the project as a whole is paused while the district gathers community feedback on remaining challenges. This is real, ongoing public infrastructure work, not an abandoned plan -- but it is explicitly focused on upstream Ross and Kentfield rather than downstream tidal flooding in Corte Madera itself, and a buyer should not assume it addresses the kind of Bay-tide-driven Highway 101 flooding seen in January 2026.

A Real Counterpoint: Marsh Restoration as Both Ecology and (Partial) Flood Buffer

Not every recent development here is bad news. In December 2020, a tidal marsh restoration project at the Corte Madera Marsh Ecological Reserve reconnected roughly four acres to San Francisco Bay through a newly constructed channel, on a 72-acre property owned by the Golden Gate Bridge, Highway and Transportation District, with more than 16,000 native plants hand-planted and habitat created for the federally endangered California Ridgway's rail and salt marsh harvest mouse. Restored tidal marsh of this kind can provide some natural flood-buffering value by absorbing tidal energy before it reaches developed areas, alongside its ecological benefit -- though this page did not find a confirmed, quantified flood-risk-reduction figure specifically attributable to this restoration project, and does not estimate one here rather than overstate its protective effect.

What This Page Does Not Know

This page does not have a confirmed, parcel-specific FEMA flood-zone designation for any individual Corte Madera or Larkspur address; confirmed Larkspur-specific flood-zone-boundary detail at the same depth as Corte Madera's own published materials; a quantified flood-risk-reduction figure for the 2020 marsh restoration; or a confirmed timeline for any permanent Highway 101 flooding fix beyond the general "years away" framing in January 2026 reporting. Get current, parcel-specific flood-zone status directly from FEMA's Flood Map Service Center, and ask both the Town of Corte Madera's and the City of Larkspur's planning departments directly whether a specific address was affected by the January 2026 event before making a purchase decision.