Flood Zones on Star, Palm & Hibiscus Islands

How These Islands Got Their Elevation in the First Place

Star Island, Palm Island, and Hibiscus Island did not exist as dry land before the late 1910s and early 1920s -- they were created by dredging bay-bottom material and depositing it to build up submerged land into buildable islands, a process completed for Star Island in 1922 under developer Carl Fisher and for Palm and Hibiscus Islands on a nearly identical timeline by the Biscayne Bay Islands Company, with the underlying land creation substantially finished by November 1919. That history matters for flood risk in a specific way: unlike a natural barrier island, whose elevation reflects thousands of years of wave and wind-driven sand deposition, these islands' elevation was an engineering decision made by their original developers roughly a century ago, built to whatever standard was considered adequate at the time -- not necessarily to a standard that anticipated today's understood flood risk, sea-level trends, or FEMA base flood elevation requirements.

One topographic-elevation data aggregator cites Star Island's average elevation at roughly 10 feet above sea level, a figure this page treats as directional only -- it comes from a modeled topographic data source, not a certified elevation survey or an elevation certificate for any specific property, and this page did not find comparable aggregator data for Palm or Hibiscus Islands specifically. An elevation certificate for a specific parcel, prepared by a licensed Florida surveyor, is the only reliable way to know an individual property's actual elevation relative to the base flood elevation FEMA has mapped for that exact location.

FEMA Zones: The General Pattern for Coastal Miami-Dade

FEMA's flood zone system designates high-risk coastal areas with a letter code: Zone AE denotes an area with a 1% annual chance of flooding (the '100-year floodplain') where a base flood elevation has been calculated, while Zone VE denotes the highest-risk coastal zones, where wave action during a flood event is expected to add significant additional force beyond still-water flooding alone. Much of coastal Miami-Dade County, including Miami Beach and its surrounding bay islands, falls within one or the other of these zones, per FEMA mapping and Miami-Dade County's own public flood-zone guidance -- oceanfront and immediately bay-exposed parcels more typically fall in the higher-risk VE designation, with more sheltered or interior locations more commonly in AE, though this pattern is not a substitute for an actual parcel lookup.

This page could not confirm the specific FEMA zone designation for individual parcels on Star, Palm, or Hibiscus Island in this research pass -- flood zone boundaries can vary from block to block, and in some cases lot to lot, depending on exact elevation, shoreline exposure, and how FEMA's mapping has drawn zone boundaries around these specific man-made islands. Confirm the exact zone for any specific address using Miami-Dade County's interactive flood-zone mapping tool or by calling the county's Flood Zone Hotline (305-372-6466) before assuming a designation or budgeting an insurance premium around it.

Why Base Flood Elevation Matters More Here Than the Zone Letter Alone

The zone letter (AE versus VE) is only part of the picture; the base flood elevation (BFE) -- the specific height, in feet, that floodwater is expected to reach during a base flood event at that exact location -- is what actually drives both building requirements and flood insurance pricing for a given parcel. A structure's lowest floor elevation relative to the BFE for its specific flood zone determines whether, and how severely, flood insurance rates are affected: a home built well above its BFE (often on pilings or an elevated foundation, common in some of this era's original construction) can carry meaningfully lower flood premiums than an equivalent home built at or below it, even within the same nominal flood zone.

Given that many of the original homes on these islands date to the 1920s through the mid-20th century -- well before modern base flood elevation requirements existed -- older, non-elevated construction here can carry real flood-insurance cost consequences relative to a newer or substantially renovated home built or rebuilt to current elevation standards. This is a genuine, property-specific due-diligence question for a buyer evaluating an older home here: ask for the property's elevation certificate, or commission one, before assuming flood insurance costs will resemble a newer neighboring property's.

The Seawall Ordinance Is a Related but Separate Standard

It's worth being precise about a distinction that's easy to blur: the City of Miami Beach's 2025 seawall ordinance (Ordinance 2025-4754, effective July 16, 2025), which sets a 5.7-foot NAVD88 minimum elevation for new or substantially repaired private seawalls, addresses the height of the physical barrier at a property's water's edge -- it is not the same measurement as FEMA's base flood elevation for that property's flood insurance rating, even though both are expressed in feet and both relate to flood risk. A seawall built to the new 5.7-foot standard helps keep routine tidal and minor storm-surge flooding off a property's immediate perimeter, but it does not by itself change a structure's FEMA flood zone designation or base flood elevation rating for insurance purposes. This page's Seawall & Bulkhead Guide covers the ordinance itself in detail; this page focuses on the separate FEMA flood-zone and insurance-rating question.

Sea Level Trends: A Regional Baseline Worth Knowing

NOAA's long-running tide gauge at Virginia Key, near Miami and within the same regional tidal system as these islands, has recorded roughly 9 inches of sea level rise since 1950, with a documented acceleration in the rate of rise since around 2006 -- regional analysis of that gauge's record found sea level rising at roughly 9 millimeters per year since 2006, notably faster than the global average rate of about 4 to 5 millimeters per year over the same period. This is regional tide-gauge data, not a projection specific to any individual parcel on these three islands, but it's directly relevant context for understanding why FEMA flood maps, city seawall standards, and insurance underwriting in this exact part of Biscayne Bay have all been moving toward higher elevation and coverage requirements in recent years rather than staying static.

What a Buyer Should Actually Do

Before making an offer on any Star, Palm, or Hibiscus Island property: pull the specific parcel's FEMA flood zone designation and base flood elevation directly from Miami-Dade County's mapping tools or the Flood Zone Hotline; request or commission a current elevation certificate for the specific structure, particularly if the home is an older, non-elevated build; and ask a Florida-licensed insurance broker to run an actual private flood insurance quote using that elevation certificate rather than assuming a generic Miami-Dade coastal flood-premium range applies. None of the general figures on this page substitute for parcel-specific data -- and given the property values typical on these islands, the cost of getting that data wrong is genuinely higher here than on a lower-priced coastal property.