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.
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. When you see the forecast guidance exceed the roadway height, you can expect flooding.
Roadway Flooding Spots
Pt. San Pedro Road near Loch Lomond Marina (between Summit Ave and Marina Blvd) typically floods when tides exceed 7.5 feet above NAVD (or 1.5 ft above average). 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.
Pt. San Pedro Road near San Rafael High School may flood when tides exceed 8 feet above NAVD (or 2 ft above average).
2nd street & Irwin may flood when tides exceed 8 feet above NAVD (or 2 ft above average).
Near Riviera Drive and McNears Brick Yard Road. Typically floods when tides exceed 8 feet above NAVD (or 2 ft above average).
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:
- 6.4 ft above NAVD (0.4 ft above avg): 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): 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): Total inundation. The road effectively merges with the marshland and is impassable in low-lying sections.
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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