St. Johns County braces for tidal flooding, wind gusts to 45 mph this weekend

St. Johns County Emergency Management is urging residents to prepare for hazardous weather conditions this weekend as strong northeast winds combine with the year's highest astronomical tides to produce widespread coastal and tidal flooding. The combination is expected to bring moderate to locally major flooding from Saturday through Monday, particularly during high tide.

Wind gusts of 35 to 45 mph are forecast for Sunday into Monday, strong enough to knock down loose objects and decorations. The National Weather Service in Jacksonville issued the warnings Friday morning, flagging the Atlantic coast, Intracoastal Waterway, and St. Johns River basin as the areas of greatest concern. County officials are advising residents to avoid flooded roadways, secure outdoor items, and stay out of dangerous surf and boating conditions through at least Monday.

What's happening

The National Weather Service Jacksonville's Friday morning briefing forecasts peak wind gusts of 35 to 45 mph beginning Sunday and extending into Monday. Moderate to locally major tidal flooding is possible along the Atlantic coast, Intracoastal Waterway, and throughout the St. Johns River basin, with the greatest flooding risk expected Saturday through Monday.

The timing coincides with the highest astronomical tides of the year. Astronomical tides are predictable, naturally occurring high tides driven by the gravitational pull of the moon and sun. When combined with strengthening northeast winds, these tides are expected to worsen flooding conditions significantly.

A high rip current risk and life-threatening beach hazards are forecast through at least Monday. Gale conditions—sustained winds of 34 to 47 knots—are possible in local coastal waters Saturday through Monday, prompting marine advisories.

St. Johns County Emergency Management issued the public-safety advisory on October 23, 2026, urging residents to take precautions immediately. The agency is asking residents to avoid flood-prone areas during high tide, never drive through floodwater, secure holiday decorations and loose outdoor objects, and postpone boating trips when conditions are unsafe.

Coastal flooding and low-lying neighborhoods

Residents in low-lying coastal areas and along tidal waterways face the most direct risk. St. Johns County's geography makes it particularly vulnerable during periods of high astronomical tides combined with onshore winds. The Atlantic coast, the Intracoastal Waterway, and communities along tributaries of the St. Johns River basin are all in the forecast zone for tidal flooding.

Tidal flooding occurs when water levels rise above the elevation of roads, yards, and in severe cases, the first floors of homes. Moderate tidal flooding typically means water overtops seawalls and bulkheads, floods low-lying streets and parking lots, and can enter crawl spaces. Major tidal flooding can block primary roadways, strand vehicles, and cause property damage.

Neighborhoods near the Intracoastal and along the river—including areas in Ponte Vedra Beach, Vilano Beach, and St. Augustine—have experienced tidal flooding during similar wind-and-tide events in the past. King tides, the colloquial term for the highest annual astronomical tides, routinely cause nuisance flooding in these areas even without wind. The addition of 35 to 45 mph northeast winds pushing water onshore is expected to significantly worsen conditions.

Homeowners in flood-prone areas should move vehicles to higher ground before high tide windows, move valuables out of ground-level storage, and avoid travel during peak tide times if possible. The specific high-tide schedule varies by location; residents can check NOAA tide predictions for local stations to time their precautions.

Road closures and travel disruptions

Flooded roadways pose serious safety hazards and are a leading cause of weather-related fatalities. Even shallow floodwater can conceal dangerous conditions such as missing pavement, debris, or downed power lines. Water as shallow as six inches can cause most vehicles to lose control, and a foot of water can float many cars.

St. Johns County Emergency Management emphasized the "turn around, don't drown" message: never drive through floodwater, and find an alternate route. Drivers who encounter standing water on roads should assume the road is impassable and turn back.

Several areas of St. Johns County are prone to tidal flooding during high-water events. Coastal roads along A1A, low-lying segments near the Intracoastal, and streets adjacent to tidal creeks in St. Augustine and along the county's extensive shoreline are the most vulnerable. During king tides and northeast wind events, some of these roads have been temporarily closed or become impassable.

The forecast period covers a weekend, when many residents and visitors may be traveling for recreation or errands. Emergency officials are urging the public to monitor conditions closely, allow extra travel time, and avoid unnecessary trips during the peak flooding windows Saturday through Monday. Real-time road-closure information is typically available through the Florida 511 traveler-information system and local emergency-management social media channels.

Wind damage and preparation steps

Wind gusts of 35 to 45 mph can move unsecured objects, snap small tree branches, and cause sporadic power outages. St. Johns County Emergency Management is asking residents to bring in or firmly secure holiday decorations, lawn ornaments, patio furniture, trash cans, and any other loose items that could become projectiles or blow into roadways.

The timing of the advisory—late October—suggests Halloween decorations may be among the items at risk. Lightweight items such as inflatable decorations, signs, and temporary structures should be taken down or anchored before the wind picks up Sunday.

Strong northeast winds also increase the stress on trees, particularly in areas with saturated soils from recent rain. Falling branches can damage property, block roads, and bring down power lines. Residents should clear gutters and downspouts to handle anticipated rainfall and secure or store anything on balconies or patios that could blow off.

Beach and marine hazards

The National Weather Service has issued a high rip current risk through at least Monday. Rip currents are powerful, narrow channels of fast-moving water that flow away from shore and can pull even strong swimmers out to sea. They are responsible for the majority of beach rescues and drownings along the Atlantic coast.

Northeast winds and large swells create dangerous surf conditions. The combination of high waves, strong currents, and poor water visibility makes swimming extremely hazardous. Beachgoers should follow posted beach-safety flags, avoid entering the water when red flags are flying, and heed lifeguard warnings.

Boaters face gale conditions in local coastal waters Saturday through Monday. Gale warnings indicate sustained winds or frequent gusts in the range of 34 to 47 knots, strong enough to create hazardous seas and risk to small craft. Emergency Management and the National Weather Service are urging boaters to monitor marine advisories and postpone trips when conditions are unsafe. Vessels should be securely moored, and equipment on docks or in open storage should be tied down or removed.

St. Johns County's Atlantic coastline and the Intracoastal Waterway see significant recreational and commercial marine traffic. Mariners should consult NOAA marine forecasts and consider delaying departures until conditions improve early next week.

Timing and astronomical context

The phrase "highest astronomical tides of the year" refers to a predictable alignment of the sun, moon, and Earth that produces the most extreme tides. These king tides occur several times a year, typically in spring and fall, and are published in tide tables well in advance.

King tides by themselves do not necessarily cause flooding, but they reduce the margin for error. When combined with weather factors such as strong onshore winds or low atmospheric pressure, they can push water levels above flood thresholds. In this case, sustained northeast winds are forecast to pile water against the coast and up tidal rivers and creeks, amplifying the already elevated tide levels.

The forecast window—Saturday through Monday—covers multiple high-tide cycles. Residents should expect the potential for flooding at each high tide during that period, not just a single event. The greatest concern is during the hours around high tide, when water levels peak.

What happens next

Residents are encouraged to monitor official weather updates throughout the weekend, as conditions and flooding impacts may change. The National Weather Service Jacksonville provides updated forecasts, marine advisories, and coastal flood warnings at weather. gov/jax.

St. Johns County Emergency Management offers multiple ways to stay informed. Residents can follow the agency on Facebook for real-time updates, sign up for the Alert St. Johns emergency notification system through the county's Emergency Management web page, and ensure notification settings allow alerts at all times.

The county has not announced any emergency shelter activations, road closures, or mandatory evacuations as of the October 23 advisory. The focus remains on individual preparedness: securing property, avoiding travel through floodwater, and staying out of dangerous water conditions.

If conditions worsen or additional advisories are issued, Emergency Management will update the public through Alert St. Johns and social media. Residents should have a plan for how to receive weather alerts, especially overnight or early morning when high tides may occur.

Weekend weather events of this type are a recurring challenge in coastal Northeast Florida. As St. Johns County continues to grow—adding thousands of new homes in low-lying areas near the Intracoastal and along the river basin—the number of residents and properties exposed to tidal flooding during high-tide and wind events steadily increases. Preparing for predictable coastal hazards, understanding local flood risk, and heeding official warnings remain essential as the region's population and development footprint expand along the water.