Northern California Flooding: Heavy Rain and High Tides Inundate Coast

This post summarizes a recent flooding event in Northern California where heavy rain coincided with exceptionally high tides, causing significant urban flooding from Sausalito to San Rafael.

I explain what happened, why the timing of the tides amplified the impacts, and what residents and local authorities did to respond.

Drawing on three decades of coastal and emergency management experience, I also offer practical safety guidance for similar future events.

Table of Contents

Storm overview and immediate consequences

The region experienced intense rainfall that arrived at the same time as record-breaking high tides, producing rapid inundation along Marin County shorelines.

Roadways along a 15-mile stretch from Sausalito to San Rafael were submerged as the event combined coastal and pluvial flooding in a short period.

The coincidence of heavy rain and peak tides created what officials described as a “perfect storm” for urban flooding.

Streets and low-lying neighborhoods filled quickly, and water levels overwhelmed usual drainage capacity.

Flooding along the Marin coastline

Local emergency responders reported water depths of three to four feet in places, trapping vehicles and necessitating multiple rescues.

Authorities indicated no injuries were reported, but they handled numerous calls about stalled cars and people stranded in deep water.

Residents were urged to stay home until waters receded.

Some neighborhoods saw unusual scenes: people kayaking down normally dry city streets and others wading through knee-deep water to get around.

The National Weather Service issued a flood warning for the affected area through 2 p.m. Saturday.

A flood advisory was extended through 2 p.m. Sunday.

Why the tides were exceptional

The event’s severity hinged on the timing of what are known as King Tides, the highest astronomical tides that occur when the sun, moon and Earth align and the moon is at its closest point to Earth.

This alignment increases gravitational pull and produces higher-than-normal tide levels.

In this case officials said the tides were the highest in more than two decades.

When that peak tidal elevation coincided with heavy rainfall the result was amplified coastal inundation and reduced ability for stormwater to drain to sea.

How the combination amplifies urban flooding

Urban drainage systems are designed to move runoff away to tidal outlets; when those outlets are blocked by unusual tide levels, water has nowhere to go.

Add intense rainfall, and even engineered channels and pumps can be overwhelmed.

That coupling of tidal and rainfall drivers is what turned a heavy storm into widespread coastal flooding.

Practical advice for residents and municipal planners

Based on long experience in coastal hazard response, preparation and clear communication can substantially reduce risk during combined rain and tide events.

Small actions by residents and system-level investments by municipalities both matter.

Immediate safety steps

If you live or work in coastal or low-lying areas, consider these actions during King Tide + storm scenarios:

Avoid driving through flooded streets — many stalled vehicles require rescue and driving through moving water is hazardous.

Follow official warnings — stay home if authorities advise and heed evacuation orders when issued.

Move valuables and important documents to higher ground — even a few feet of water can cause major damage.

Have an emergency kit ready — include a flashlight, batteries, phone charger, water and first aid supplies.

Report trapped people or vehicles to emergency dispatch — let trained responders handle rescues.

Longer term, communities should invest in resilient drainage and maintain natural buffers like wetlands.

Incorporate tide forecasts into stormwater planning.

Here is the source article for this story: Heavy rain, high tides cause flooding along stretch of Northern California