Be aware that sections of Point San Pedro Road tend to flood during high tide events, especially during periods of heavy rain that increase the normal tides. Please note that forecasting water levels is a mix of predictable astronomy and unpredictable weather. Click here for a more thorough explanation of tides, flooding and predictions. Note that tide levels you see on the news may not match tide levels on our roadways due to differences in timing and tide levels throughout the bay area.
Water Level Forecasts
Some people check the astronomical tide charts before heading out to see if high tides are high enough to cause flooding and when the flooding might occur. However, astronomical tide charts do not take into account other weather factors, such as winds, currents, rainfall, or atmospheric pressure that can affect both the timing and height of the tides.
We recommend checking NOAA’s inundation dashboard for a better forecast of water levels. When viewing the NOAA chart, we recommend looking at the light blue line labeled “Forecast Guidance” because it It blends the pure astronomical predictions (darker blue line) with oncoming weather systems, combining tide cycles with winds, storm currents, and air pressure. For example, during a strong El Nino, thermal expansion raises the baseline and tides consistently run 6 to 8 inches higher than predicted, while during a La Nina, the water is cooler and denser and tides routinely peak lower than the astronomical tide charts. A very strong El Nino can increase the average water levels by 1-2 feet above the astronomical tide charts and, as you can see in this next example, in Oct 2026 we were already seeing water levels 1ft to 1.5 ft+ above the astronomical tide prediction.
In this example, you can see that on 10/11, the astronomical high tide prediction (dark blue line labeled “Predictions”) was 6.16 ft, which would not cause flooding. However, the NOAA forecast (light blue line labeled “Forecast Guidance”) was 2 feet higher at 8.17 ft. The observed water level (red line) turned out to be 7.8 ft, slightly below the NOAA forecast and 1.6 feet above the astronomical tide chart. At this level (7.8 ft), most of Pt. San Pedro Road would dry, except for some minor flooding near Marin Yacht Club Marina. The lower lying sections of N. San Pedro road would have been passable only by high-clearance vehicles.
Roadway Flooding Spots
When you see the forecast guidance exceed the roadway height, you can expect flooding in these areas:
Pt. San Pedro Road near the Marin Yacht Club Marina (between Summit Ave and Marina Blvd) is typically the first spot to flood when tides exceed 7.4 feet above NAVD (or 1.4 ft above average high tides). During rainfall events, the water level may be higher than predicted tides due to runoff flowing into the San Rafael Creek.
During the very strong El Nino in 2026/27, the County is planning to deploy temporary tidal flood barriers along Point San Pedro Road in this area. These barriers are intended to help reduce the impacts of tidal flooding during periods of extreme high tides and winter storm conditions.
When going west on Pt San Pedro Road, you can detour around this section by turning right on Summit Road and then using your GPS app to direct you to your destination. Click here for a video of what it looks like when flooded or see the photos below.
Pt. San Pedro Road near San Rafael High School may flood when tides exceed 8 feet above NAVD (or 2 ft above average high tides).
2nd street & Irwin may flood when tides exceed 8 feet above NAVD (or 2 ft above average high tides).
Near Riviera Drive and McNears Brick Yard Road. Typically floods when tides exceed 8 feet above NAVD (or 2 ft above average high tides).
N. San Pedro Road near the main China Camp Entrance. A 1.5-mile stretch of North San Pedro Road sits alongside the bay tidal marshes and portions of it are quite low relative to the tides. When extreme high tides occur (winter and summer “sunny day” king tides and winter storms), they flood the roadway and cannot drop until bay tides drop. Big winter storms also can add large runoff from the adjacent watershed and the undersized culverts force this runoff across the road even when tides are low and more deeply when tides are high. If a winter storm brings heavy runoff from the hills when tides are only moderately high, the road will flood just as badly as it would during a “sunny-day” 7.5-foot King Tide because the water cannot drain out into the rising Bay.
These low-lying road sections typically flood earlier than other road sections listed above. When there is no storm runoff, these are general guidelines for how the tides affect flooding along the low-lying sections. Note that after a tide that is high enough to spill over the road (6.4+ feet) and add lots of water to the interior mark, the road tends to stay flooded for an hour or more after the tide recedes because it takes time for the water from the marsh to flow back over the low sections of the road and drain through the culvert, which is a slow process.
- 6.4 ft above NAVD (0.4 ft above avg high tides): Water will begin washing over the low-lying shoreline edges, specifically near the main China Camp Entrance.
- 7.0+ ft above NAVD (1+ ft above avg high tides): Water covers multiple low stretches of the road. High-clearance vehicles might pass with caution, but standard sedans risk stalling out.
- 8.0+ ft above NAVD (2+ ft above avg high tides): Total inundation. The road effectively merges with the marshland and is impassable in low-lying sections.
How Deep is Too Deep?
Saltwater is highly corrosive to vehicles, hides hidden roadway damage, and can stall out a car in just a few inches of water. Click here for official guidance from the National Weather Service on Flood Safety. Key things to know:
- 6 Inches: The depth at which water reaches the bottom of most passenger cars, potentially causing loss of control. Can damage low-hanging electrical sensors and cause immediate vehicle stalling.
- 12 Inches: The depth required to float small passenger cars. Tires lose all friction with the asphalt, leaving you with zero steering or breaking control.
- 18–24 Inches: The depth that will float larger vehicles like SUVs, trucks, and vans and lead to mechanical failure.
- Hidden Hazards: High-tide saltwater rapidly degrades electrical components, and standing water can easily conceal missing manhole covers, sharp debris, or washed-out pavement
The Bottom Line: If you can’t see the pavement or the painted road lines, do not guess the depth, turn around! Click here for a video illustrating the danger.
Sandbags
Free sandbags are currently available in our area at these locations:
- Peacock Gap Park, 699 Biscayne Dr. Parking Lot
- San Rafael Rock Quarry Dutra Materials‘ sandbag station is open during business hours (7am-3pm Mon – Fri except holidays) and ready to assist our San Pedro Road corridor in preparing for weather events. The sandbag station is located on the left-hand side of the entry road to the quarry once you have passed through the gates.
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