Coastal Flood Advisory in Effect Today – See If Your Shoreline Is at Risk

Monday, July 21 2025 — A string of Coastal Flood Advisories has been issued up and down the U.S. shoreline today as astronomically high tides collide with lingering on-shore winds, raising the risk of minor to moderate inundation in low-lying communities. Northern California: The National Weather Service in Eureka placed the coastline from Humboldt Bay southward under an advisory through early Tuesday after weekend swells piled water against beaches and river mouths. Tide gauges at Crescent City and Humboldt Bay are forecast to briefly exceed flood stage late this evening, threatening Highway 101 frontage roads, harbor parking lots and the lower reaches of the Eel and Mad Rivers. Residents are urged to move vehicles off waterfront streets and avoid walking jetties during the late-night high tide. Cape Fear Region, North Carolina: Similar concerns prompted forecasters in Wilmington to post a Coastal Flood Advisory for New Hanover County from this afternoon through midnight. Persistent easterly flow behind a weak frontal boundary is expected to push Cape Fear River water levels 1–2 ft above normal during the evening tide cycle. Portions of River Road, Battleship Park and downtown Wilmington’s Riverwalk could experience ponding, while island communities from Carolina Beach to Wrightsville Beach may see saltwater over topping storm drains. New Jersey and Delaware: Farther north, a full-moon tide combined with a modest on-shore fetch is forecast to nudge back-bay and marsh levels over bulkheads from Atlantic City to Lewes this evening. Though no widespread damages are expected, nuisance flooding may block low-lying streets such as West End Avenue in Brigantine and the White’s Creek area near Bethany Beach. Why it’s happening: Coastal flooding does not always require heavy rain. Today’s setup features: • Perigean spring tides: The moon is near perigee and full phase, adding several inches to baseline high tides. • Residual swell: A departing frontal system over the western Atlantic left behind long-period waves that continue to drive water toward shore. • Sea-level rise: NOAA’s annual high-tide outlook shows the Mid-Atlantic and Gulf coasts now average 4–9 in higher mean sea level than in 2000, lowering the threshold for flood advisories. Potential impacts tonight: • Road closures on causeways, particularly during the two-hour window around peak high tide. • Saltwater intrusion into storm-water systems leading to street ponding and backed-up sewers. • Erosion of dune faces and tidal creek banks, especially where recent storms have already weakened sand berms. • Minor overwash on bayfront properties; unsecured boats at floating docks could strain lines. Safety and preparedness tips: 1. Check local tide tables and the NWS forecast office page before traveling near the coast. 2. Never drive through saltwater; six inches of moving water can stall a vehicle, and brine accelerates corrosion. 3. Elevate electronics, lawn equipment and HVAC units in crawl spaces prone to flooding. 4. Marinas should double-line vessels and remove loose gear from docks. 5. Share photos of rising water only from safe, elevated positions—rogue waves can sweep over seawalls without warning. Looking ahead: Advisories may be re-issued Tuesday evening along the Southeast and Mid-Atlantic as the lunar cycle continues. Forecasters remind coastal residents that nuisance flood days are projected to increase sharply over the next decade, underscoring the need for updated flood-mitigation plans and resilient infrastructure. Stay tuned to NOAA Weather Radio, local emergency management channels and real-time tide gauges for the latest coastal flood updates.