Lake Ontario Coastal Risk Areas

The objective of the Risk Area Maps is to define areas at risk from coastal and riverine hazards, distinguishing significant differences in the exposure of the landscape. Data was collected from sources accurate enough to differentiate geographic areas according to the likelihood of flooding, erosion, waves and overtopping from storm or high-water events within the project area. To the extent allowed by source data, places where flood water can extend up streams and under culverts and bridges are reflected in mapping. Compiling mapping into a summary, classifying geographic areas according to differences in vulnerability.  The following datasets were overlaid, and combined vulnerabilities were used to discriminate geographic areas into three classes: 
Extreme Risk Areas- Areas at greatest risk of frequent inundation or vulnerable to erosion were created from the overlay of the maximum extent of the following datasets to create the Extreme Risk Area: 

  • Area at or below the Ordinary High-Water Elevation (247.3ft IGLD) 
  • Coastal areas with greater than 1% chance of flooding that are also susceptible to hazards associated with storm waves. 
  • Soils in which the likelihood of flooding is likely to occur often under usual weather conditions or is expected infrequently under usual weather conditions (approximately 5 to 50 times in 100 years). 
  • Dynamic natural shoreline feature areas susceptible to flooding and erosion. 
High Risk Areas: Areas outside the Extreme Risk Area that are at a less frequent, but high risk of inundation were created from the overlay of the maximum extent of the areas upland of the boundary of the Extreme Risk Area was compiled from the following datasets: 
  • Area bounded by the 1% annual flood risk zone (FEMA A zones). 
  • Riparian Buffer Area 
Moderate Risk Areas: Areas outside the Extreme and High-Risk Areas but currently at moderate risk of inundation from infrequent events. 
  • Area bounded by the 0.2% annual risk (500 year) flood zone, where available. 
  • Area bounded by the base flood elevation plus 2 feet of vertical elevation.
  • Soils dominated by running water or formed by water-deposited sediments. 
View Dataset on the Gateway

Data and Resources

Field Value
dcat_issued 2022-08-29T12:18:41.000Z
dcat_modified 2025-10-17T20:17:18.000Z
dcat_publisher_name New York State Department of State
guid https://www.arcgis.com/home/item.html?id=1d682b9b946042b9a5dbc389266a66b8&sublayer=0
Tags
  • Climate Change and Resilience Program
  • Great Lakes Program
  • Resilience and Community Infrastructure
  • coasts
  • hazards
  • recovery planning
isopen False
metadata_created 2026-08-19T14:50:32.056694
metadata_modified 2026-09-22T21:38:54.044196
notes The objective of the Risk Area Maps is to define areas at risk from coastal and riverine hazards, distinguishing significant differences in the exposure of the landscape. Data was collected from sources accurate enough to differentiate geographic areas according to the likelihood of flooding, erosion, waves and overtopping from storm or high-water events within the project area. To the extent allowed by source data, places where flood water can extend up streams and under culverts and bridges are reflected in mapping. Compiling mapping into a summary, classifying geographic areas according to differences in vulnerability. <div>The following datasets were overlaid, and combined vulnerabilities were used to discriminate geographic areas into three classes: </div><div><u><br /></u></div><div><u>Extreme Risk Areas-</u> Areas at greatest risk of frequent inundation or vulnerable to erosion were created from the overlay of the maximum extent of the following datasets to create the Extreme Risk Area: </div><div><ul><li>Area at or below the Ordinary High-Water Elevation (247.3ft IGLD) </li><li>Coastal areas with greater than 1% chance of flooding that are also susceptible to hazards associated with storm waves. </li><li>Soils in which the likelihood of flooding is likely to occur often under usual weather conditions or is expected infrequently under usual weather conditions (approximately 5 to 50 times in 100 years). </li><li>Dynamic natural shoreline feature areas susceptible to flooding and erosion. </li></ul><u>High Risk Areas</u>: Areas outside the Extreme Risk Area that are at a less frequent, but high risk of inundation were created from the overlay of the maximum extent of the areas upland of the boundary of the Extreme Risk Area was compiled from the following datasets: </div><div><ul><li>Area bounded by the 1% annual flood risk zone (FEMA A zones). </li><li>Riparian Buffer Area </li></ul><u>Moderate Risk Areas</u>: Areas outside the Extreme and High-Risk Areas but currently at moderate risk of inundation from infrequent events. </div><div><ul><li>Area bounded by the 0.2% annual risk (500 year) flood zone, where available. </li><li>Area bounded by the base flood elevation plus 2 feet of vertical elevation.</li><li>Soils dominated by running water or formed by water-deposited sediments. </li></ul></div><div><a href='https://opdgig.dos.ny.gov/datasets/1d682b9b946042b9a5dbc389266a66b8/explore' target='_self' rel='nofollow ugc'>View Dataset on the Gateway</a></div>
num_resources 2
num_tags 6
title Lake Ontario Coastal Risk Areas
url https://data.gis.ny.gov/maps/NYSDOS::lake-ontario-coastal-risk-areas